Popular Science Monthly 1925-09: Vol 107 Iss 3

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: we Sgt INVENTIONS . | ul ay DISCOVERIES q RADIO ’ AUTOMOBILES | PBCICACES uisiow MONTHLY HOME WORKSHOP “4 = ~~! — - J e 4 i> vf NSP a ee eee SS A ay > 3s ? —) Dw Se = es Ka oh ee See ee J aA eee, i ina SR Le oe # <P Fs. ik, ‘ v & SVE cee 2s . b . Bare 2 pi a pee App tee ~ J . . a f= . . e @ Oe ee ee ee oe BS a i il at i a kal q SEPTEMBER Giant plane designed to cross Atlantic in a day 25 CENTS | $10,000 Prize Contest—See Page 31

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Look for the Red Handle with the Black Head (Color Combination registered as trade mark inU.S. Patent Office) EXCLUSIVELY PLUMB Instantly, with a turn of the wrist, you retighten the head of any Plumb Tool. V-shape of wedge expands wood of handle against all sides of eye all the way in. Black head on red handle means a better hammer EE what PLUMB has done to give particular tool-users a hammer they will appreciate. a lot of hard use. With its larger face, for accuracy; Its shorter neck, for better balance; Its claws improved in pulling power; Its head specially tempered—hard for service, tough for wear— AND THE TAKE-UP WEDGE TO KEEP IT NEW. The Plumb Take-Up Wedge retightens the black head of this hammer with a turn of the wrist. It keeps all Plumb heads tight on Plumb red handles. The Take-Up Wedge preserves The PLUMB Balanced Nail Hammer s a. i At good hardware stores A hammer, too, that will retain its good qualities through $1.30 (except in Far West and Canada) balance and hang and accuracy. It keeps Plumb tools (exclu- sively) good as new! FAYETTE R. PLUMB, Inc. Philadelphia, U. S. A. DOUBLE LIFE PLUMB Hammers Hatchets r | Files Sledges Axes SB Cros.

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YT /a' td September, 1925 Startling/ Revolutionary/ ‘ Crosley owns and operates Super-Power Broadcasting Station WLW POPULAR SCIENCE MONTHLY i developnents of Powel Goshey It This compact, efficient receiver is an improvement of the famous Crosley one tube set, with which Leonard Weeks, of Minot, N. D., heard the MacMillan Polar expedition while the rest of America listened in vain. The employment of the double circuit not only reduces radiation to a minimum, but radically improves selectivity. It can be tuned through local stations more readily. Under average conditions, its radius, with head phones, is 1500 miles or more. You can use the ‘‘PUP”’ to check the performance of your larger set; to entertain that youngster whose curious fingers cannot resist the lure of dials and switches; to install in the maid’s room, or even your office—for the air is full each day. You can take it on canoe trips, picnics, outings, and on your business journeys—for it’s only half the size of-a shoe box. It is not offered as superior to the higher priced sets. There 7s a difference in volume of sound—but no difference in receptivity, selectivity, tonal qualities—or the enjoyment it offers. The Crosley ‘‘Pup” is offered as a real selective, long distance re- ceiving set. It requires one dry cell, one ““B”’ battery block, one WD12 tube, a pair of head phones and_antenna. wIiTHOUT ACCESSORIES New CROSLEY Super-TRIRDYNS for 1926 3 Tubes Do the Work of 5 or 6 You have not heard the perfection of radio reception until you have listened to these two new Super-Trirdyns. In them the need for more than three tubes is eliminated by the famous Trirdyn hock-up—which combines tuned radio frequency, Armstrong regeneration and reflex amplification. There is no radiation. Distant stations come in clear and sharp on the lcud speaker and can be accurately logged. Offered in solid mahcgany cabinets of exquisite beauty and design, these new mcdels are the aristocrats of radio recepticn at democratic prices. New Super-Trirdyn Special The finest development of the famous Crosley Trirdyn—beautifully done. A _ magnificent cabinet of solid mahogany—simple in design. Richly finished with engraved metal dials. The case is large enough to contain all needed batteries if dry cell tubes are 560 used. Price, without accessories - - Add 10°, to All Prices West of Me MUSICONES Rocky Mountains An Improved Loud Speaker a ee = “loud speakers’’ will be re- placed by the Musicone in this, its first year. The Musicone reproduces the full tonal range of the human voice and music without distortion, over tones, resonance or chat- tering. It requires no ad- justments nor additional batteries. The patented ac- tuating unit is the secret of its faithful reproduction of all tones. Not the mere cone. Beware of imitation cone speakers. Covered by basic patents. Price 75° Musicone De Luxe The Musicone has been artis- Heally combined. with 2 clock 0 e aul ul mal any with a grilled screen. ice $27.50 Combination De Luxe The new Super-Trirdyn Special Luxe Combination designed by Crosley and built by Crosley cabinet workers. it consists of a haxdsome sold mahogany table, the Super- De 27.50. Com. $Y 12.5° auie, “Wete te bination - - The New Super-Trirdyn Regular A beautiful cabinet job! Simple, yet rich. Oil rubbed solid mahog- any. Art metal dials give dis- tinctive finishing touch. With new Trirdyn features incorpo- rated itis a wonderful $ value at the price, be, 6F without accessories - Radical Improvements in Other Popular Crosley 2 and 3 Tube Models! a | 4 ' , i a New 2 Tube—51 Special Deluxe ¥ 'y) These low priced ‘models represent radical improve- 4 § — a ments in selectivity, performance, appearance and : a Sai vilue. More selective control and improved re- 8 it ceptivity have been achieved by the use of the new Ad worm type tickler, the new Crosley vernier plate con- denser and the double circuit. Price without TRIRDYN accessories. - New 3 Tube—52 Special Deluxe This model like the 61 contains the new Crosley improvementsand represents also as the 51 new beauty Tricdyn Special (batteries self con- i > tained) and the Musicone De Luxe. aan bay X 50 separately if desired. Table Por dry cell bat- 25. Musicone h sories. THE CROSLEY RADIO CORPORATION © Crosley manufactures receiving sets which are licensed under Armstrong U. S. patent No. 1,113,149 and priced from $9.75 to $60 without accessories. See the Crosley line at your dealer’s © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 19. CINCINNATI Write for descriptive catalog

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Popt SEPTEMBER, 1925; Vol. 107, No. 3 25 cents a Copy; $2.50 a Year

lar Science Monthly! The Magazine of Invention and Discovery Published in New York City at 250 Fourth Avenue y

Coming Next Month In the Wild-Animal Hospital—The remarkable experiences of a daring surgeon who has performed more than 1500 operations on lions, elephants, monkeys, and many other wild animals. A story packed full of dramatic episodes. Long Life to Your Tires—In another entertaining “Gus and Joe” story next month, the two proprietors of the Model Garage give some valuable tips on how to take care of your tires. If you haven’t met these two fascinating characters, you can make their acquaintance on page 76 of this issue. What Radio Set Shall I Build?—That’s a question many a radio fan is asking himself this fall. In an article next month our Radio Editor will help you answer it. More than 200 other fascinating articles and pictures, giving you all the news of radio engineering, science and inven- tion, strange and unusual things people are doing, together with practical ideas for the automobile, the home, the home workshop, and the use of tools and machinery. HE world’s most mysterious man is writing his story for POPULAR SCIENCE MONTHLY; one of the most fascinating in the whole wide field of science. The secrets he reveals answer questions that have been rising in the minds of most of us since childhood. Watch next month’s issue, on sale Septem- ber 10, for the an- nouncement of this amazing series.

Repairing the broken leg of an ” 4 cidents in next month’s story of the experiences of a wild-ani- mal surgeon, who has performed more than 1500 operations e—one of many interesting in-

POPULAR SCIENCE MONTHLY Issued Scocatiy. le copy, 25 cents. Yearly subscription to United States, f untries, $3. mtered as second class matter Dec. 28, 1918, at the ie ce at New York under the act eS arch 3, 1879; additional entry as second-class matter at Dunellen, N. J. Entered as second-class matter at the ce Department, Canada. Printed in U.S.A. Copyright, 1925, by the Popular Science Publishing Co., Inc The dhs of this magazine must not be reprinted wit ceed rmission. In presenting in its editorial cuheinns numerous stories of new products of applied science, PoPULA' cx MONTHLY does not underwrite the business methods of the individuals or concerns producing them. The use of PopULAR SCIENCE MONTHLY articles, or quota- tions from them for stock-selling schemes 2 never authorized O. B. Capen, President and ssions, and Canada, $2.50; reasurer; R. C. Wilson, Vice-President; A. L. Cole, Secretary.

In This Issue Popular Science Institute of Standards .. Earthquakes 2 By Arthur Selwyn Brown, Ph.D., L.L. b 23 ew York to Paris in a Day By Truman Stevens. The Power that Lies in Your Eyes By Arthur Grahame Can We Pum i from the Earth? . . By Ernest Welleck America’s First Rotor Boat............. Twisted Paper Box and Aviation By John R. McMahon Hunting Wild Beasts vd Flashlight $10,000 Prize Contest Marvels of Marine Workmanship. . "at's @ btign Pressure JOD’. ...... 0.04649 By Frank Parker Stockbridge How Fast Can You Go? By Robert E. Martin Sea Gliders—The Last Word in Aircraft. . Poisons that. Lurk in ‘“‘Bootleg Booze’’. By Norman C. McLoud Shoe-Leather From Sharks............. He Staged More Battles than Napoleon.. By Fred Gilman Jopp Air-Drift Recorder Aids Pilots New Aids for the Deaf Automatic Instrument Sends SOS Calls . .. Sun-Gazer Forecasts Weather Revolving Eraser ew Retreading Process Electric Pointer for Schools ............ Multi-Side Razor-Strop.............. , How to Shave Your Own Neck......... Spring Shoe Is Lots of Fun Novelties of the Road................. Fire-Fighters Go to School............. Battering-Ram Aids Firemen. New Synthetic Motor Fuel Pipe-Wrench Has Reversible Jav T-Square Held by a Magnet Parking Tower for Autos Latest Novelties in Aviation Sailing Canoe Serves as Tent Stilts Are His Stepladder Stool Folds Into Handbag Drawing Device Trains Student’s Eye.... Child’s Chair Is Adaptable to Many Games 58 He Does Two Things At Once Vacuum Cleans Furnace Flues. ..... Dustproof Hood for Cleaning Furnaces. . “Mystery cmap Lights when Picked Up 60 h Safety Device Shuts Off Gas............ 60 Rolling-Pin for Weight Reducing........ 6l Metal Frame for Concession Tent 61 Metal Honeycomb Doubles Bees’ Output. 61 New Ideas for the Kitchen. ............ 62 Camp Stove Heated by Blowtorch...... 64 1000-Watt Lamps Grow Grass. ......... 64 Ceiling Insert of Steel... . .. 66... es ae 64 Collapsible Hand-Cart................. 64 Largest Power-Generating Station....... 65 Folding, Unsinkable Rowboat........... 65 Auto Converted into Fire-Engine........ 65 Gasoline Tiller Replaces Horse. ......... 65 Mousetrap Set by Foot................ 65 Wor Patm: ONG Garden. «.. << .0c- wesc 66 They Don’t Come Any Bigger.......... 67 AMON osig os s.6 80 5 oc bare oie bs oS 68 SW Pe RRR ES oc Sik crs 5.25. 6 oso a eves 68 Patent Gripper for Climbing Girders..... 68 Heart-Shaped Glasses for Actors........ 68 Three-Pointed Pen Aids Bookkeepers.... 69 One-Piece Suit for Tennis.............. 69 Smoking-Tube Is Latest Fad........... 69 How Much Do You Know?............ 69 How to Select Your Batteries........... 70 By John Carr When Is a C Battery Worth While?.... 72 By Alexander Senauke, M.E., E.E. OR NM TS Repos oracle laws o.9' 9.6 06 73 How to Make a Wave Trap............ 74 By Alfred P. Lane Newest Auto Improvements............ 75 bi in a BOONES cise eschew sane 76 Martin Bunn uselul Hints for the Autoist............ 78 The Home Workshop...... 79 Better Shop Methoads...... 84 And Other Timely Articles and rn <

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September, 1925 POPULAR SCIENCE MONTHLY Putting a Screwdriver through the Mill By DAVID B. PORTER, Ph.B. Here a screwdriver is undergoing the ‘‘torsicn test,” which determines the degree of tough- ness of the blade. A weighted arm is clamped to the screwdriver handle. Angular deflec- tion on the chart indicates blade resistance HE screwdriver is perhaps our simplest tool—so simple, in fact, that its misuse is mastered readily and we sometimes wonder if it is not misused more than used. When some ice is wanted, and the pick has rolled under the icebox, the feminine members of the family invariably seize upon the screwdriver and hammer. Or, when that new piece of furniture arrives firmly crated with stout nails, the screw- driver again is resorted to with the hammer following it up. This time it is not only used as a crowbar, but tried out as a cold-chisel when some misdirected blows drive the edge half through a nail. In devising tests for screwdrivers, it is obvious that the Popular Science Insti- tute of Standards can consider only the legitimate uses for which they are de- signed. But, as our tests have proved, there are any quantity of screwdrivers on the market that will not stand up under even normal usage. Such screwdrivers (as well as other tool and radio products that do not pass the Institute’s tests) cannot be advertised in POPULAR SCIENCE MONTHLY. HE chief requirements for screw- drivers are that the blades be suf- ficiently hard to resist wear and prevent rounding corners, and tough enough to turn the screw without being twisted. There is a limit, however, to the degree of hardness, because brittleness also increases with the hardness and a blade that is too britile soon breaks at the corners. The degree of hardness is measured by the scleroscope—an instrument that has had very wide commercial use in testing the hardness of steels. From the results of such tests, it is possible for the engineers of the Institute to tell whether the blades have the right degree of hardness. The toughness of the blades, or their Popular Science Institute of Standards The wearing qualities of the spiral mechanism of this ratchet screwdriver here are subjected to a test in a few hours that equals many years’ ordinary usage ability to resist twisting, is determined by our ‘““Torque Test,”’ which is illustrated at the left of the page. An arm is clamped to the screwdriver handle and successive weights are applied. For each weight the angle of twist is read on the scale behind the pointer, and from this the load in pounds-inches is determined. The angu- lar deflection on the chart tells instantly how the steel of the blade is acting as the R © a POPULAR SCIENCE Monthly Guarantee The above seal on an advertisement indicates that the products reférred to have been approved after test by the Popular Science Institute of Standards. Popular Science Monthly guaran- tees every article of merchandise advertised in its columns. Readers who buy products advertised in Pop- ular Science Monthly may expect that these products will give abso- lute satisfaction under normal and proper use. Our readers in buying these products are guaranteed this satisfaction by Popular Science Monthly. THE PUBLISHERS. ln Es load increases. The torsion applied in this test exceeds that which could be exerted by the strongest mechanic. In the case of the spiral ratchet screw- driver it is necessary to go further than a test of the blade, and to determine the wearing qualities of the spiral mechanism. By use of ingenious tests devised by the engineers of the Popular Science Institute of Standards, it is possible to give this mechanism many years’ wear in a single afternoon. HE illustration on the right shows how this is done. The tests are carried out on a shaper, the traveling head of which gives the reciprocating motion needed to produce the kind of wear that would develop any defects in the mechan- ism of the tool. Exact measurements are made of the amount of wear occurring in the spiral mechanism. The pressure against which the reciprocating head works has been predetermined by estab- lishing the pressure exerted by a mechanic in driving a screw into an oak block. In addition to the above tests, the screwdrivers are inspected for finish and workmanship, the handles for security, and ratchets and locks are carefully tested to see that they function easily after the screwdrivers have been subjected to further severe torque and wearing tests. Send for List of Approved Products

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POPULAR SCIENCE MONTHLY September, 1925 S-L-F Condenser “Get rid of small wis- dom and great wisdom will shine upon you.” Chuang Tzu, It is great wisdom to buy the Synchrophase. 5 Peele Another exclusive Grebe feature:,One dial can oper- ate all three—or they can be set separately at will. © oi Again Grebe Steps ahead— mane The Synchrophase now has i One, Two or Three-dial Control HE three condensers operate from one dial—or separately at will. This first real, flexible form of “unit-control” marks another milestone on the road of Grebe leadership. The new Synchrophase has the same Binocular Coils which give that unusual “selective sensitivity” so universally prized; the same Straight-Line-Fre- quency Condensers that make accurate tuning easy. Ask your dealer to demonstrate ; then compare A. H. Grebe & Co., Inc., Van Wyck Blyd., Richmond Hill, N. Y.. _ New York Office: Steinway Hall, 109 West 57th Street TRADE MARK @EGUS PAT. CFF, All Grebe appa- tatus is covered ~ by patents grant- ed and pending. PAT OFF Synchrophase is also supplied ". with base for batteries — This company owns and operates stations WAHG and WBOQ; also mobile and marine low- wave rebroadcasting stations. Western Branch: 443 So. San Pedro Street, Los Angeles, Cal. ORT RES © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 19.

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POPULAR SCIENCE MONTHLY SUMNER N. BLOSSOM, Editor September, 1925 Cracks in the Karth Menace Big American Cities Sczentists See the Need for More Widespread Knowledge of Earthquakes and Their Causes By Arthur Selwyn Brown, Ph.D., LL.D. can is that he may be living in an area of earthquake danger. It is only following disasters such as the recent ones in Santa Barbara, Calif., and Mon- tana that people in this country realize that earthquakes are phenomena not con- fined exclusiveby to the more remote regions of the earth. As a matter of fact, earthquakes occur in the United States every year—many of them. More than that, they occur in places that point to the existence of definite lines of earth weakness passing through or near some of our greatest cities. New York, Washington, and Boston, for example, lie along one of these lines, and consequently are not entirely removed from the danger of earthquake. Other similar lines are found stretching BOUT the last thought, probably, A that occurs to the average Ameri- that moves, and resilient houses would usually not be injured by an earth tremor. A severe shock in any of the cities that lie along the faults or lines of earth weakness in this country would have most calami- tous results with buildings of the existing type. A few far-sighted men have recognized this danger. Thus, almost immediately following the Santa Barbara earthquake, the owners of one of New York’s most famous skyscrapers obtained a_ large insurance policy against possible damage to the building from earthquake. Seismologists have, during the past 10 years, given attention to the world’s principal volcanic zones. They have mapped the areas where the most numer- ous and pronounced earthquakes are recorded. These show that there is a across the continent from southern Cali- fornia to the Atlantic Coast, sweeping up through the Mississippi Valley to the Great Lakes, and cleaving the center of New Eng- land. Within these areas live millions of people. To alarm them is not my intention. What I wish to do is to call at- tention to the pressing need of an _ intensive seismological survey of the United States and Canada—a work that too long has been neg- lected because its im- portance has not been foreseen. There is need, too, for our architects, engi- neers, and builders to develop proper founda- tions and earthquake- proof houses for regions where earthquake dangers exist. It is the ground, not houses, Santa Barbara, Santa Barbara’s Ruins State Street, the main street of Calif., hours after the recent terrific quakes hurled masses of masonry and debris from shattered business buildings into the middle of the wide streets, leaving behind a scene of destruction a few line of weakness encompassing the earth, starting in the Aleutian Islands and running through Alaska to California, Mexico, South America, the south polar continent, New Zealand, Tasmania, the east coast of Australia, Japan, and thence northward to the Aleutians again. HERE is another belt around the Mediterranean, running to Persia and thence northward to Nova Zembla and the North Pole. The Mediter- ranean belt is linked with the Pacific bel- by a zone traversing the northern port tions of South America and running under the Atlantic to Morocco. Another line parallels this to the north. It runs through the Caribbean Sea, across the Atlantic to Great Britain and then along the Norwegian coast until it connects with the Asiatic line passing Nova Zembla. A study of the annual reports of earthquakes in the United States plainly shows that there is also another im- portant line of weak- ness starting in the southern parts of Cali- fornia, traversing Ari- zona, following the thirty-fifth degree of latitude, sending a spur up the Mississippi and Ohio rivers, then run- ning eastward to the sea, and thence follow- ing the coastal ranges up to Prince Edward Island and Newfound- land. Another line of weak- ness in North America may be found in Can- ada. The Great Lakes and the St. Lawrence were formed along fault planes that are still lines of voleanic weak- ness. The activity of the Saguenay fault in the St. Lawrence River is well known. It is 21

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22 not so well known, however, that a similar line of faulting is shown by the great rivers, lakes, and waterways stretch- ing through Canada from the Atlantic to the polar seas near the Alaskan boundary. Whenever there is earthquake activity in California or in our southern and eastern states, we may be sure to find similar activity in Alberta, Saskatchewan, and Manitoba. The influence of earth faults in developing rivers and lakes has beeh shown lately by seis- POPULAR SCIENCE MONTHLY down in the earth’s interior. These dis- turbances recur in violent outbursts about every 10 or 12 years and always are accompanied by marked changes in climate. The present summer of 1925, during which the Santa Barbara earthquakes and the shocks in the eastern states and else- where occurred, has been remarkable for its humidity, high barometric pressures, and frequent thunderstorms and electri- September, 1925 The earth carries a great weight of air, Any increase in this weight must make a considerable differen ce in the strains acting upon the thin crust of the earth. All who have worked in deep mines know that when there is a high barometrical pressure, the column of air in a deep shaft greatly increases in weight, and work in deep mines becomes increasingly arduous. ' When unusual climatic conditions occur in any given locality, there must be enough added pressure on the mologists who have studied the voleanic history of the eastern coast of Africa. Rift valleys containing lakes, swamps, rivers, and other water bodies run from Cape Town, through Nyanza, Taranki, Rudolph, and other lakes, to Abyssinia, where a large rift valley, triangular in shape, exists between Abyssinia and Somaliland. The Nile runs almost parallel to this East African earthquake zone, and that river apparently courses along a series of faults. EW YORK affords a clear case of river development by faulting. The Harlem River, which’ joins the Hudson and East rivers, flows through fault F gorges in gneiss and limestone “INI IsvoD 5s SAGUENAY. FAULT —" come cameo Se, \. MISSISSIPPI \.-- VALLEY earth strains to cause the rup-: 4 ture of many weak zones that must cause a sinking, sliding, faulting, or folding of the rocks, J LECTRICAL and magnetic forces operate in a similar manner. ‘The earth is a large magnet surrounded by innumer- able and powerful lines of magnetic force. These lines ‘of magnetic force are surrounded by electric lines of force begin- ning at the south magnetic pole magnetic pole. The rocks and molten material. of the earth’s interior are charged with mag- netism and the earth’s rotation serves to generate vast electric “THE 3 niet TY and magnetic currents. . Here we have a great natural dynamo constantly creating rocks. The dropping of large areas of rocks, just as those that followed the earthquakes in San Francisco and Santa Barbara, undoubtedly preceded the first flowing of the Harlem River. Here is one established fact showing the structural weakness of the earth in New York. The valley of the Hudson appears to follow lines of faulting also. These faults are connected closely with the rising of hills and mountains in the same or distant localities. The earthquakes in California are along lines of faulting. They par- allel the sea and the coastal mountains. In the sea are deep depressions called on the charts “‘deeps,’”? which are points of earthquake activities. The majority of severe quakes in recent years have occurred along lines of weakness near one or more of these deeps. There are many such deeps in the Atlantic, off the eastern states of America, and in the Pacific, off our western coast. ‘There is one off the Antilles; others are off Charleston, Cape Lookout, the Great Bank of Newfound- land, and the Azores, Canaries, and the Cameroons in the Atlantic. Still others are off San Francisco, Alaska, and Mexico, in the Pacific, besides many more off the coast of South America, in the South Seas, and around Australasia. SIMILAR points that play prominent parts in disturbances in India and the Himalayas occur in the Indian Ocean, off Java, and in the Malay Archipelago. When the mountains rise, these deeps sink, indicating that earthquakes are not merely local phenomena, but are evi- dences of forces exerted upon the whole unstable crust of the earth. What these forces are has not been determined. The best evidence indi- cates that earthquakes are caused by electrical disturbances originating far Earthquake Belts in the United States This map of the United States, based on earthquakes that have occurred in the past, shows the principal lines of earth weakness. Some of these pass through or near some of our greatest cities. New York, Washington, and Boston, for example, lie along one of these lines that follow the Atlantic coastal ranges to Canada cal displays, all over the United States. There is such a close correspondence between the periods of earthquake activity and the appearance of spots and prominences on the sun that some ob- servers have assumed that earthquakes are caused by sun-spots. The truth, however, is that the sun-spots and vol- eanic activities on earth are merely evi- dences of the same universal forces of nature in operation. - xa) ia . a . a J Mn & @ me Ad Pe cae te * : Se = os 2 4 4 Py a =~ Where the Earth Cracked The recent severe earthquakes in central Mon- tana opened up great fissures near the town of Great Forks, where the property damage was estimated at $500,000. The crevice shown here is 100 feet long, in some places from two to five feet wide and from two to eight feet deep enormous electric and magnetic currents that are sent off into space to create new stars, suns, and planets. And we may view the sun, planets, and stars as acting in the same way. The sun alone sends down to the earth enough electric and magnetic energy to cause enormous disturbances in the earth’s magnetic and electrical fields and to profoundly change the position of the earth’s apex ana in- tensify the strains on the earth’s crust. It is electric and magnetic waves of this character, coming from the sun and other stellar bodies, or, perhaps in some cases, _from electrical ruptures in the clouds, that cause the principal earthquake and voleanic activities on the earth’s surface. To be able to predict earthquakes, we should have world-encircling climatic and electrical observation stations to secure data to use in conjunction with seismo- logical and astronomical data. The study of seismological data alone will never enable us to anticipate new volcanic activities. i MOWING that earthquakes occur in their greatest intensities along lines of earth weakness, we should study the lines of weakness in the United States so as to be able to antieipate those parts that are most likely to be visited. To simplify this work, we might sketch a map to show the principal lines of faulting and the locality where earthquake shocks are of frequent occurrence in North America. The whole western coast, between Alaska and Mexico, is well known to be on one of the greatest lines of weakness. The Pacific bed is falling, the coastal ranges are increasing in height, and the seacoast is bearing the greatest of the compression strains. The oceans grad- (Continued on page 124) and winding spirally to the north: Al

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+ 1925 f air, ake a cting | who that sure, eatly deep uous, occur: - the rup-: that ding, ocks, netic nilar large mer- } ae 2s of nded egin- pole orth : and rth’s nag- ition ctric ‘ural ting 1etic into uns, sun, g in lone ctric 10us and inge in- It this ther ises, uds, and ace. we and ure mo- udy ver nic >in nes the } SO hat To .a ing rth en SS. tal she she id- September, 1925 POPULAR SCIENCE MONTHLY New York fo Paris in a Day! By Truman Stevens ITHIN the next five years we shall see giant transatlantic air- planes that will carry at least 75 passengers from New York to Paris in 26 hours, and at a cost less than present passage on large steamships! This prophecy comes, not from an idle dreamer, but from a hard-headed, practi- cal designer of airplanes, a pioneer in aviation. He is Louis Breguet, French airplane manufacturer, whose factory in Paris is said to turn out more machines on a commercial basis than any other plant in the world. The working plans for such an air monster already have been completed, according to reports from Paris, but M. Breguet expects that the machine will not be built, tested, and ready for trial flight before five years. On this page and on the cover of this issue our artist has pictured how the great passenger plane, as described by M. Bre- guet, may appear in flight over the sea. The machine will be of all-metal con- struction, with twin bodies, capable of alighting on either land or water. With a load of 75 passengers, freight, and baggage, it will weigh 55 tons. Power will be supplied by eight motors develop- Famous Designer Plans a Gigantic Air-Liner to Carry 75 Passengers Louis Breguet, French air- plane manufacturer, study- ing plans for the giant passenger plane with which he expects to establish 26- hour transatlantic service between New York and Paris. Above is our artist’s conception of how the great aire liner may look ing a total of anout 5000 horsepower. Luxurious passenger quarters in the two hulls and in the wings will include eight first-class cabins, 52 second-class, and 15 third-class. The first-class cabins will be six feet high, six feet wide, and 10 feet long. In addition, there will be a restaurant with electrical cooking equip- ment throughout, and a reading-room and lounge where smoking will be permitted. The crew of the giant seacraft will include, besides the commander, a chief electrician and assistant, two pilots, eight mechanics, four cooks, and a wireless operator. It has been estimated that the cost of building the plane—about $2,000,000— will be covered by receipts from 20060 hours’ flying time. The passenger fare for each trip, it is predicted, will average about $200. According to present plans, the trans- atlantic flight in summer will be charted on a non-stop course between New York and Paris by way of Newfoundland, while in the winter a southern route will be taken by way of the Azores. As you look at the artist’s fascinating picture you can imagine yourself boarding the big ship at a New York flying-field, some morning in the near future, soaring out over the sea, plunging through the sky at terrific speed for a day and a night above the vast expanse of ocean, and finally arriving in Paris bright and early on the following morning.

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POPULAR SCIENCE MONTHLY September, 1925 The Power that Lies in Your Eyes Amazing Electrical Tests Explain the Mysteries of Man’s Ability to Rule Wild Beasts —— me onnage” a HE man cracks a whip and gazes commandingly at the tiger. The tiger glares its hatred for a moment, then looks away. Most dangerous of all the jungle clan, it could tear its tormentor to shreds with a few swift strokes of its. mighty claw-armed paws. Instead, it cowers, trembling and, unwilling but submissive, goes through detested tricks. This man who, armed with no weapon more deadly than a light whip, dares to match his will against the strength and ferocity of the most dangerous of animals, is no professional tamer of wild beasts. He is Charles W. Beall, senior vice presi- dent of an old and conservative Wall Street banking house. Many of the big men of New York’s financial district have their hobbies. Some sail racing-yachts on Long Island Sound. - Some play polo at Meadowbrook. Others collect paintings. Mr. Beall trains wild animals. Instead of a polo stable he maintains a menagerie. Standing with him in the building at Woodhaven, L. I., where he keeps his animals—at present the collection in- cludes two tigers, three lions, three ele- phants, six leopards, one jaguar, and two monkeys—I asked him what gave him his unusual power over the lords of the jungle. “Oh, just ‘animal sense,’ I guess,” he replied. “A combination of a love of animals and an understanding of them.” A GOOD answer from the practical animal - trainer’s viewpoint, but science has one even more convincing. From a London laboratory comes news that Dr. Charles Russ, an English physi- cian formerly connected with the electric- ity department of the Male Lock Hospital in London, has proved that the gaze of the human eye contains energy in some form—probably electro-magnetic energy By Arthur iene —powerful enough to swing a suspended wire coil through an angle of 60 degrees! Such proof of radiation of power from the human eye—its intensity varying with individuals—would seem to explain the mysterious ability of some men and women to subdue and dominate the strongest and most vicious of animals. A few moments’ talk with Mr. Beall convinced me that he was a man of ex- ceptional personal magnetism, and that it had been his unrealized possession of this very power of the human eye that had first turned his thoughts toward his avo- cation of animal training. “Other boys collected stamps,’ said Mr. Beall; ‘I collected animals. I can hardly remember the time when I didn’t have animals. I grew up with them.” “‘Where?”’ I asked, with visions of a —— Ea. ae How Human Gaze Moves Wire Coil |-SILK THREAD SET SN ~> b MAGNET fs ‘ € A Doctor Russ’ experimental apparatus—a wire coil suspended by a thread inside a metal case and held steady by a magnet. The fixed gaze of human eyes, it was found, caused the coil to move from its former position Why Man Is the Master Doctor Russ’ ag. > tonishing experi. ments indicate that \ actual radiation of electrical power from the human eye is the force that enables the animal trainer to rule and tame the wildest beasts boyhood spent at some African trading- post. “Right here in New York City,’ replied Mr. Beall, smiling. ‘“‘We lived in a big house, and I kept my menagerie in the cellar. I started with a bowl of goldfish. After that I had dogs and rabbits and squirrels. But such pets didn’t satisfy me for long. I wanted something more un- usual. eve a long time I had followed the doings of the great animal trainers of that period with the same interest that boys of to-day follow the pitching of Walter Johnson and the home-running of Babe Ruth. I got to know some of these ‘animal men’—fellows who made their living by capturing, training, and dealing in rare and dangerous beasts. Through one of these men I made my first real wild- animal acquisition-—a pair of bear cubs. “A little later I got a young leopard. A puma cub and an alligator followed. Before I was out of my teens I had added hyenas, panthers, and more leopards. By this time the cellar menagerie had be- come impossible. I had to move my ani- mal collection to a farm in New Jersey, where I kept it for many years.” O PERFECTLY trained are Beall’s animals that he puts them to work for a part of each year. They have delighted thousands of visitors to New York’s great playground, Coney Island, have performed in the New York Hippodrome, and have been rented to motion-picture production companies. *‘And all those years, while you were working up from squirrels and bear cubs to elephants and tigers, you were learning how to control animals?” ‘“‘ ‘Learning’ is not exactly the right word,” replied the banker-trainer. ‘‘ ‘De- riati is a beat shov duri fron deci in tl atte mak stea appi neceé whe it, a und eye sus} side “chi coil. sma soul coil an ¢ the dire obs was mez wir in t If 1 ‘ones

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8 aster iS as. te that tion of >Ower 1uMan force €s the her to ne the casts ling- plied _ big the fish. and 7me the ners that of g of 1ese heir ling one ‘ild- ibs. ard. 7ed. ded rds. be- ani- ey, Il’s for ted -k’s ave me, ure ere ubs ing 4 ‘no’? would be more accurate. You vet is largely a matter of instinct. The real secret of animal training is bluff. If you can keep up your bluff, you are safe. I never ‘learned’ to train animals; I de- yeloped 2 natural ability.” Just what is this mysterious natural ability? The experiments conducted py Doctor Russ during the last eight years supply an answer—the electric power of the human eye. Doctor Russ claims to have proved that the ordinary man can move a sus- pended inanimate object by looking at it steadily. Developed to high intensity, it is probable that this electric eye power is what enables men like Mr. Beall to quell the ferocity of dangerous beasts. HE evidence of modern science sup- ports the belief that the human body isactually an electric power plant. All the muscles show electrical currents and va- riations of potential during action. There is an electrical change with each heart- beat. ‘The retina of the eye has been shown to exhibit minute electrical activity during vision. Whatever the force coming from the eye might be, Doctor Russ decided, a part of it probably wouldradiate in the form of electricity. Unlike Mr. Beall, Doctor Russ did not attempt to demonstrate this power by making a tiger leap through a hoop. In- stead, he constructed the simple piece of apparatus shown in the __ illustration. To demonstrate his theory, it was necessary that an object would move when the human gaze was directed on it, and to do this the object had tobe placed under such conditions that nothing but eye power could account for the move- ment. Doctor Russ made a wire coil and suspended it by an unspun silk thread in- side a metal case. One end of the thread was fastened to a cork at the top of the “chimney”; at.the other end hung the coil. Just above the coil he fastened a small magnet, which, taking a north- south position, held the coil steady. The coil itself was so adjusted that it was in an east-west position. A small window in the metal case allowed the gaze to be directed at the coil, and made possible the observation of any movement. A scale was arranged below the coil for accurate measurement of the movement. Electrical science has taught us that if a varying magnetic field meets a coil of wire, an electric current is generated with- in the coil and the coil becomes a magnet. If this magnetic coil is free to move, it POPULAR SCIENCE MONTHLY Tigers Obey His Will Charles W. Beall, New York finan [Be Me Poll ss cier, whose hobby for years has been the training of wild animals, and whose remarkable power over tigers, lions, elephants, and jaguars is explained _ by electrical radia- tions of the eye will turn into the earth’s magnetic me- ridian—into a north-south position. To do this, the coil in Doctor Russ’ appara- tus would have to overcome the force ex- erted by the magnet above it. This magnet, already in its proper north-south position, would object to being swung out of it. If, when the experimenter’s gaze was directed on the coil, it moved against this force, it would prove the electric power of the human eye. Doctor Russ took his station a short distance from the metal case and began to gaze steadily through the window at the coil. One second—no Two, three, four seconds— still no movement. Five seconds—the coil started to swing! Within 10 seconds it had turned several degrees toward a north-south direction, forcing the little magnet above it out of its proper position. Doctor Russ looked away. The coil swung back to its east-west line. De- prived of power from the eye, it could not keep the magnet from asserting its pull. Continuing the trials with improved apparatus, Doctor Russ found that the first result had been no freak. For the wire coil he substituted a cylinder made (Continued on page 121) movement. The Most Mysterious Man in the World t- of the most extraordinary series ever pre- sented—the story of Houdini, the greatest ma- gician of all time, the wonder worker who for 35 years has mystified the entire world—will begin in the next issue of POPULAR SCIENCE MONTHLY. Houdini is more than a magician. of broad learning, a scientist, author, student, and philosopher. He numbers among his friends many of the greatest men of our time. He has been called the most mysterious man in the world. Houdini. He is a man Only one man knows Houdini’s secrets. And Houdini has written his own story so frankly, vividly, and intimately, that as you read you feel you are face to face with him hearing the fascinating narrative from his own lips. OU cannot afford to miss a single word of this en- thralling series. acter sketch of Houdini, will appear in the October issue, published September 10. Order your copy now! That is The introductory article, a char-

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UNITS RACE FOPULAR SCIENCE MONTHLY ; ITH the rapid dwindling of the ~ world’s natural resources in stored fuel—coal, oil, and gas— engineers and scientists in recent months have been turning to the problem of tapping and harnessing the vast reservoir of heat in the interior of the earth. The latest plan, and one of the most ingenious and elaborate, developed by Rudolf Lammel, a German engineer, is pictured here. It proposes drilling two shafts, one straight, the other with a. number of rectangular bends, to a depth of three miles. This depth is about 21% times that of the deepest shafts ever drilled. Both shafts lead to-a large sub- terranean chamber cut out of solid rock. If we estimate that with every 100 feet downward the temperature rises one de- gree Centigrade, the temperature of the walls of that chamber will be approxi- mately 166° C. or 330° F. At a depth of three miles the air pressure is estimated at nearly two atmospheres, or about 30 pounds to the square inch. The boiling point of water under this pressure would be 248° F., more than 80 degrees lower than the temperature of the chamber. ROM a reservoir on the surface, water is sent down through a pipe that follows the bends and turns of the stepped shaft to the chamber at the bottom. As the water rushes downward, it becomes gradually hotter, and at a depth of nearly two miles it turns to steam, which is forced into the chamber by pressure of the column of water above. In the high temperature of the chamber the steam is The proposed plan to utilize the earth’s interior heat. circulation of water that is turned into steam in a chamber three miles down E Gn We Pump Power from the Earth? By Ernest Welleck September, 19 Dotted lines and arrows show superheated and expanded. It seeks an outlet through the straight shaft. Reaching the surface, the superheated steam is distributed first to the turbines of a light and power station, then to various industrial establishments and tc residences and public buildings, wheré it is used for heating purposes. HAVING given up its heat energy, the water is collected again in a reservoir, from which it is pumped back to the pipe, resuming once more its voyage to the natural heat plant and completing the cycle—water, steam, water. Even on its downward flow to the underground steam chamber, the water is put to work. At the lower end of each vertical section of the staggered conduit, a turbine driving an electric genergtoar is inserted. The turbines in the upper two miles are water turbines; those in the remaining part of the shaft, steam tur- bines. The electric power thus generated is conducted to the’surface to be used for driving pumps and other machinery re- quired in running the heat and power plant. The energy to be derived from a plant of this description, of course, depends on the volume of water available. Assuming that a constant flow of 13 cubic yards a second is obtainable, as it is in many existing hydraulic power plants, the po- tential energy made available by heating that volume of water to 330° F. would be equal to nearly 3,000,000 kilowatts a day, representing an economic value equal to 70,000 tons of good coal a day. Septem! ] | ship de Flettn few m' it sail Baltic passe specta watch age poat iz Charle bridg Amer struct: naval first a tion it how a tower vas Sa Lie stitut were in re] cided acqui 30 fee disca up tl In gathe aviat some been Mag The effec Tl roto! follo Tl cylir Dect cylir frict

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eeks an rheated Cur bines then to and te where gy, the servoir, 1e pipe, to the ng the to the vater is of each duit, a tor is er two in the m tur- erated sed for ory re- power 1 plant nds on suming ards a many he po- eating uld be a day, jual to september, 1925 POPULAR SCIENCE MONTHLY America’s First Rotor Boat Naval Officers Embody New Ideas in Odd Craft HE interest with which the strange rotor ship designed by Anton Flettner was greeted a few months ago, when it sailed out into the Baltic Sea, little sur- passed that of the spectators who recently watched the trial voy- age of the first rotor poat in America, on the Charles River at Cam- pridge, Mass. This American boat, con- structed by two young naval officers, was the first actual demonstra- tion in this country of how a revolving metal tower can replace can- vas sails. Lieutenants Joseph M. K. Kiernan and W. W. Hastings, students is experimenting now with a single-tower sys- tem of propulsion as indicated by one of his latest designs—a rotor yacht that recently appeared in Germany in competition with sailing-yachts. The cylindér designed by Lieutenants Hast- ings and Kiernan for the American craft is 34% feet in diameter and 9% feet high. This is small- er in proportion than the tower used on the original Flettner ship, anditrevolvesat greater speed. On the Flettner ship, at the top of each of the cylinders, was a rim projecting about 14 inches. The pur. pose of this was to maintain the suction in naval architecture at the Massachusetts In- stitute of Technology, were greatly interested in reports of the rotor ship. They de- cided to build one for themselves. They acquired an abandoned navy cutter about 30 feet long and eight feet wide, and with discarded materials from other boats fixed up the rotor apparatus. In designing the tower they used data gathered in exhaustive experiments in aviation at Langley Field, Va., where for some time the United States Army has been studying the application of the Magnus theory of air pressures to aircraft. The American boat employs the Magnus effect, just as the German boat does. The Magnus principle, as applied to a rotor boat, may be expressed as follows: The wind hitting the side of a rotating cylinder goes around with the cylinder. Decreased air friction on one side of the cylinder creates suction. and increased air friction on the other side causes pressure. mm, recently near Berlin. A spectacular race between new Flettner single-tower rotor yacht and a sailboat, staged Flettner’s first rotor ship had two towers The sailboat won. These two forces, together, move the boat. The American boat differs in several respects, however, from Flettner’s craft. While the German inventor used two cylinders on his 600-ton boat, the Ameri- cans decided to use only one on their cutter. They believed that when two cylinders were used, one interfered with the other’s action. Fiettner also appar- ently has come to this conclusion, for he *, ~ cn and pressure zones ex- tending up and down the opposite sides of the cylinder, and to prevent air from entering these zones from above and disturbing them. These rims re- volved with the cylinders. The disk used on the top of the American’s rotor tower is stationary. The rotor tower is mounted in the middle of the boat on a ball-bearing base and is sup- ported by an interior column. It is driven by a five-horsepower motor located at its base. In the first test of the boat on the Charles River, its estimated speed was about three knots (nearly 3% land miles) an hour. With the tower rotating at 360 revolutions a minute in a 15-mile wind, the designers believe their boat will attain a speed of seven knots (about eight land miles) an hour. They estimate that it would require 10 horsepower to drive a boat of the same size six miles an hour by propell.r. Its development is an indication of future rotor uses. America’s first rotor boat on its trial trip. It was designed and built from an old 30-foot naval cutter by two young naval officers, Lieuts. Joseph M. K. Kiernan and W. W. Hastings. Its estimated speed was about 314 miles an hour

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SN A STL NT A ASE pa POPULAR SCIENCE MONTHLY The Air Conquered Wilbur Wright flying the successful glider of 1902. The operator, lying on his stomach and clutching the controls, had to shift his weight quickly to bal- ance the craft and avoid a crash. The author of this article was one of the first to report the epoch-making experiments of the Wright brothers. He writes from personal experience and observation HEN Orville Wright an- nounced last spring that he would present to an English museum the pioneer air- plane in which he and his brother Wilbur made historic flight on December 17, 1903, there was quite a stir in this country and abroad. President Coolidge hoped that the machine might be kept at home. There was promise of Congressional action, both to retain patent models in America and to investigate Mr. Wright’s charge that the Langley relic in the Na- tional Museum at Washington had been refurbished improperly, manipulated and labeled to support a priority claim. We can wait for Congress to clear up the Langley matter, which, after all, is a question of “might have” or “afterward also” rather than “did fly first.”” Mean- while it is interesting to have a bit of light thrown on the yet obscure details of the Wright brothers’ independent ard marvel- ous achievement. Their story, despite world-wide publicity, is still to be told. One reason for this is the death of Wilbur, the elder brother, in 1912. The First Wright Glider The first actual heavier-than-air machine built by the Wright brothers, embodying their idea of warping, was this glider flown in 1900 at Kitty Hawk. Its wing span was 18 feet, with a chord of five feet. This pic- ture shows one of the experimental flights, with the glider used as a kite, operated by cords from the ground The young bicycle men of Dayton, Ohio, had been discussing the problem of flight for about three years when the first real idea came to them in June, 1899. They had spent Sundays lying on their backs beside the Miami River, hoping to learn something from the stately maneu- vers of hawks and buzzards in the blue overhead. Then came that first real idea, which was Orville’s—to obtain lateral balance by hinged wings. “The hinge is a good idea, but not practical,” agreed the brothers after debate. This was their judgment as expert mechanics. The bicycle shop that the young men conducted was kept open late evenings to cater to the trade of factory employees. Where the Airplane Was Born The original camp built by the Wright brothers in 1900 at Kitty Hawk, N. C,, birthplace of the airplane. Orville and Wilbur are seen hard at work on one of their numerous experimental glider models, with a small boy as spectator How a Twisted Paper Box Gave Us Aviation By John R. McMahon Wilbur was on duty one night in July, some weeks after the hing concept had been argued and seemingly discarded. A customer came in. If he had asked for tire tape, a wrench ora pump, the course of history might have been changed. But this cy tomer asked for an inner tube fa his bicycle tire. That tube was packed in a rectangular pasteboard box. Wilbur held the empty box by its ends while the custome examined the contents. Wilbur's hands were inclined to be nervously active. He looked down and sué- denly realized what he was doing with an empty box—twisting it— warping it. What was this? Can't hinge wings? Never. But you can warp them! Eureka! Wilbur closed the shop in a huny and rushed home to tell Orville. Usually each brother, in the interest of truth, savagely assailed the other’s idea. This time Orville heard the box story, made no argument, and just accepted Wilbur’s warping amendment to the hinge principle. Then and there one half of the problem of lateral balance of the airplane was solved for all time. It was simply a great inspiration, like Newton’s falling apple. ‘THE Wrights had a cozy home on Hawthorn Street and there was much affection among its four dwellers— brothers, sister. and father. The mother had died some years before. Katharine had taken her place as far as possible. Hom¢ facto! The recre’ in th aroul dwell addi W sche! it ou Semi ence kite, the here

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2 night in the hinge rued and If he had ench ora ory might t this cus r tube for tube was asteboard mpty box customer Wilbur’ nervously and sud vas doing sting it— is? Can't it you can in a hurry nterest of ier’s idea. Ox story, accepted ; to the here one valance of time. It ‘ion, like home on here was lwellers— 1e mother Katharine possible, geptember: 1925 uscinating Glimpses of the Airplane’s Barth Revealed for the First Time by One of the Early Associates of the W right Brothers Home love and unity were also factors in the birth of aviation. The “boys” always found their recreation and deepest enjoyment in the home circle. They tinkered around and improved the frame dwelling with their own hands, adding a porch among other things. Within a month after the warping scheme came to them, the Wrights tried it out on a box kite that they flew from Seminary Hill in Dayton. A large audi- ence of small boys begged to assist. The kite, a five-foot biplane, acted badly from the small boys’ viewpoint—it scooted here and darted there like mad, but satis- fied its makers, since it responded to the control cords that twisted its frame. EXT in order was to test the idea in a man-carrying glider, which the brothers started to build the following winter. Wilbur pioneered the first trip to Kitty Hawk, N. C., in the fall of 1900 and on the way was almost wrecked in a fishing boat. Mrs. Tate, wife of the local postmaster, let Wilbur use her sewing- machine to stitch together the wing POPULAR SCIENCE MONTHLY In Camp at Kitty Hawk—A Room Full of Great Ideas Interior of the shed camp de luxe at Kitty Hawk in 1902, showing Wilbur Wright at work on the glider of the previous year. coverings of the glider. In return for this courtesy it was only fair that next year the postmaster’s little girls should be wearing very fancy dresses of cream- hued sateen, made out of glider wings. And if those dresses still remain, they are certainly heirlooms! The brothers had agreed to take turns in going up. Wilbur had the first air ride, Orville holding a rope tied to the machine. How that winged broncho bucked! It danced, it cavorted. Alarmed by its gyrations at the dizzy height of perhaps 10 feet above ground, the co-sire of aviation yelled in his sharp staccato: “Lemme down! Lemme down!” Afterward, when teased by his family for “Lemme down!”’ Wilbur always had an alibi, that he had promised his father to take care of himself; and every- In this camp Orville officiated as chef, running his kitchen mathematically body, including himself, would laugh. While the warping principle passed the test in pioneer voyages, the brothers now saw flaws in the classic air tables on which curves of planes and other things depend. _Home again, they tried to solve the mysteries of air pressure with a whirling wind-vane attached to the front of a bicycle. A young man pedaling around Dayton with such a contraption naturally gave pleasure to spectators. One of the latter must have been clair- voyant of the secret purpose, for he was heard to state: “That fellow can run his gizzard out, but he’ll never make that thing go up!” At a later period, amid a skepticism almost universal, the brothers found one true believer, Charles Webbert, landlord of their bicycle-shop quarters. It is touching to think of An Epoch-Making Moment—Start of the First Power Flight This is one of the most prized photographs in the world. air at the end of its monorail runway. the pilot. It was snapped at Kitty Hawk December 17, 1903, just as the Wrights’ first power plane took the Orville was t As the machine startéd down the track and into the wind, Wilbur ran at the side holding the wing to balance the machine. had risen about two feet. He was able to stay with it until it lifted after a 40-foot run. A member of the Kill Devil Hill life-saving crew snapped the camera an instant after the machine had left the track and Wilbur is seen still running at the side, watching the historic first flight this first convert—a landlord to boot. How it must have en- couraged the young experimenters! They did thank him for his faith, regardless of its basis. It seems Mr. Webbert was a spirit- ualist and thought the brothers flew by .aid of the spirits. A larger glider was planned for the next year and again Wil- bur stitched up the wing covers, but this time on the family sewing-machine and on the side porch of the Wright’s home- stead. Any passer- by on Hawthorn Street could see that lean, sharp-eyed young man laying out muslin on the grass, snipping it in bias (Continued on page 128)

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30 POPULAR SCIENCE MONTHLY September, 1925 samcest @ Hunting Wild Beasts made his remarkable close- up photographs of jungle be ©“ by Flashlight Thrilling Jungle Photos at Close Range AMERAS instead of rifles; flashlights in place of gun- powder—these were the hunting weapons used in the wilds of African jungles by Major Radclyff Dugmore, daring naturalist, artist, and explorer, in obtaining the remarkable photographs of big game pictured on this page. Only twice did he use a rifle, and that was when angry lions, whose pictures he was seeking, charged him. Major Dugmore’s method was to find out the animals’ own kill and lie in wait for the return of the killer, at a distance of about 10 or 12 yards. Below is an extraordinary picture of a wounded lion, one of two shot by Major Dugmore after they had charged him. This was taken at a dis- tance of only eight yards from the roaring beast Many nights were spent by Major Dugmore in the black depths of the jungle to obtain this remarkable flashlight picture of a spotted hyena This lioness, returning to her own kill, suddenly spied the camera- man 10 yards away, who at that instant set off the flashlight A huge rhinoceros charging, photographed 3 ; at range of 16 yards. When aroused, this 4 is one of the most dangerous animals Hippopotamuses, sunning themselves on the bank of a river, all unaware of the photographer aes nee ee sii SO ose: iE toe i enero eg

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aber, 1925 CS ge Still to Be Won! 444 Cash Prizes in Our Remarkable $10,000 Contest “’VE been so busy making mistakes in a new home of my | own that I haven’t had time until now to worry about the mistakes of John and Mary Newlywed,” writes a Detroit suburbanite. ‘“‘Am I too late to try for a prize in your $10,000 picture contest? And if not, how can I get in?” No doubt others have let the weeks slip by since our great cash prize contest was announced in the June issue and are asking a similar question. There is still plenty of time for everybody. Although the fourth and final set of “What’s Wrong” pictures appears in this issue, on the next two pages, there still remain exactly 444 out of the original 580 cash prizes to be awarded. That means that you have an equal chance with everybody else to win one or more of 444 prizes totaling $8000. The first thing to do is to turn this page and look at the eight contest pictures for September. The contest has to do with the enthusiastic but inexperienced efforts of John and Mary Newlywed to do odd jobs about the home they have just moved into. Each picture shows John or Mary doing one of these jobs in the wrong way. And in addition, our artist has deliberately drawn one thing in each picture in- correctly. What you are to do is to find what John or Mary is doing wrong, why it is wrong, and what mistake the artist has made. You can practise on the picture at the bottom of this page, which was printed as an example, to show you how to go about the contest. First, what is John doing wrong? Obviously, he is varnishing a table in the smoke from the back yard incinerator. If you don’t know, you can easily find out why this is wrong and how it should be done. Next is the observation test. What mistake has the artist made? What about the shadows? Is it right that the shadow cast by the varnish can should fall in a direction opposite to that of all other shadows? ; THE eight pictures published this month form a complete contest in themselves. Similar sets of eight pictures appeared in the June, July, and August issues, making four complete monthly contests in all. And, in addition, there is a Grand Prize Contest in which $6000 in prizes will be awarded for the best answers submitted for all 32 pictures in the four monthly contests. The last two of the monthly contests, as well as the Grand Prize Con- test are still open for your entry. You have until August 30 to submit answers to the pictures in the July contest, and you have POPULAR SCIENCE MONTHLY Your Last Chance to Win One or More of These Big Prizes [X THE June issue we offered $10,000 in 580 cash prizes for the best answers submitted in this contest. Of these prizes 444 still remain to be awarded. The prizes offered in each monthly contest are: Peet PHO, yo. ss Svc v awe $500 Some Pree: . «ov. aces ica vem $100 Thee Petes... ....... 2200p eeee $50 5 Princes, $20 ench. . 008i cee $50 60 Prizes, $5 cach. .:.....22 i $300 Total, four months In addition, cash prizes in the Grand Con- test will be paid as follows: First Grand Prize............. $2500 Second Grand Prize........... $1000 Third Grand Prize............. $500 5 Grand Prizes, $50 each.......$250 50 Grand Prizes, $10 each 250 Grand Prizes, $5 each..... $1250 Total Grand Prizes............ $6000 Practise on This Picture In this sample ‘‘What’s Wrong” picture, John is seen var- nishing a table in the smoke of the back-yard incinerator. Why is this wrong? You will see, too, that the artist has made the shadow from the varnish can fail in the wrong direction until September 30 to submit answers in this month’s contest and in the Grand Prize Contest. If you have mislaid your copies of the June, July, and August numbers, and if your newsdealer cannot supply you, copies of these issues may be examined free at the offices of this magazine or in the public libraries. If you wish, you may obtain copies at 25 cents each from the Picture Contest Editor, Popular Science Monthly, 250 Fourth Avenue, New York City. It costs you nothing to enter. All you need is to be ob- servant and alert. You can sub- mit as many sets of answers to the pictures as you wish, and if you run into difficulties you can call on members of your family, your friends, or neighbors for assistance. But before you start to write your answers, be sure to read the rules of the contest. These you will find on page 122 of this issue. ‘THE names of the prize-win- ners in this month’s contest will be announced by the judges in the February issue of POPULAR SCIENCE MONTHLY. Winners of the Grand Prizes will be announc- ed as soon as possible after the close of the contest. Three judges, members of the staff of the Pop- ular Science Institute of Stan- dards, will decide on all awards. Remember the final date— September 30. Better sit down now and write out your answers while there is still plenty of time. You are sure to find the contest fascinating and profitable. COMPLETE RULES FOR THIS SENSATIONAL ‘“WHAT’S WRONG” CONTEST ON PAGE 122

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32 POPULAR SCIENCE MONTHLY September, 195 A $10,000 Test W a W ee of Observation hat S | rong In and:-Alertness In Each John Is Doing Something} = y | Made One Error] in Se Se RR RTT 1 John isn’t satisfied until the garage door is padlocked 2 Mary’s desire for an extra shelf in the bedroom gives * against auto thieves. He purchases a hasp and staple, and * John another chance to use his new set of tools. Here he is seen here as he energetically tightens the last of the screws is starting the last screw in the angle bracket shelf support a") 3 This is John’s first experience in removing a tire from its 4 John loses no time in adopting Mary’s suggestion for a * rim. But with the aid of a couple of tire irons and a * catch-lock on the door. It looks so easy that he an- hammer he sets boldly and confidently to work on the job ticipates nothing but a perfect job when he has finished it

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ber, 1925 In Ning Tror gives ere he ipport September, 1925 These Pictures? Wrong, and in Each the Artist Has in the Drawing POPULAR SCIENCE MONTHLY 33 Read the Rules of This Amazing Contest—Page122 Pil The woodwork in the breakfast nook is too dark and * gloomy, Mary thinks; so John gets a can of white enamel and starts enthusiastically painting the trim around the window 6 Mary’s electric iron refuses to work. Taking it apart, John * discovers that a wire is broken in the heating unit. Eagerly, though with little experience, he proceeds to solder the break 7 Though he knows little about electrical appliances, John * determines to give the noisy electric fan a thorough oiling, Here he is undertaking the job with enthusiasm 8 Mary protests at the appearance of the radio storage bat- * tery in the living-room. Eager to please her, John con- ceals the battery in the closet and runs the wires under the rug

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34 Marvels of Marine Invention POPULAR SCIENCE MONTHLY September, 1925 Two Boats in One A racing sailboat with a double hull—two pontoons connected by cross braces—is the novel idea of an Italian inventor, Luigi Penco A Floating Lighthouse The floating brick residence shown at the right is one of the world’s oddest lighthouses. It is located off the coast of New London, Conn. Latest Rivals of Naval Warfare Despite repeated assertions by experts that the warship is doomed, warships still are being built on a larger scale than ever before. The latest type battleship, represented by the 30,000-ton Nelson and Rodney laid down in England, is 700 feet long, capable of steaming 24 knots, and carrying six 16-inch guns. It is pictured here, together with a Ger- man naval architect’s recent conception of the modern battleship’s greatest rival, the giant submarine cruiser Sep

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r, 1925 ‘ip is i by land, ying Ger- dern uiser September, 1925 68 A RIES “It’s a High Pressure Job”’ POPULAR SCIENCE MONTHLY This remarkable photograph shows sandhogs at work in the muck at the bottom of a great caisson for the new Hudson River vehicular tunnels connecting New York City with the New Jersey shore—the biggest tunneling P é project ever completed. Here, at highest air pressures, a =. a good day’s work is half an hour, for which the pay is $12 Where Halt an Hour Is a Day’s Work Thrilling Experiences of a Veteran Sandhog, Who for 30 Years Worked Deep in Catssons and Tunnels “CNURE I like it. Why shouldn’t I? S Short hours, big pay, an’ easy work into the bargain. Who wouldn’t like a job like that, I’m askin’ ye?” Paddy Ryan, veteran “sandhog,” spat emphatically into the gutter as he de- livered that eulogy of his day’s work. Paddy was just through with his job in the Hudson River vehicular tunnels, the biggest tunneling project ever completed, with the twin 30-foot tubes making an under-water roadway for automobile traffic between New York City and the New Jersey shore. And being the biggest of all under-water tunnels, it was the biggest sandhog job on record. Twelve hundred of these men, doing their day’s work below the river-bed, had burrowed those mile-long holes through. the mud, and some of them—Paddy Ryan for one —were proud of their achievement. From where we stood, in West Street on the New York water-front, we could see the towering steel skeleton of the city’s newest skyscraper. The clatter of the pneumatic riveting hammers re- sounded like the tattoo of a flock of giant woodpeckers. Paddy took a long puff By Frank Parker Stockbridge at his pipe, removed it from his mouth and waved it in the direction of the sound. ‘‘Now, them boys,” he said, with an inimitable burr that defies type, ‘“‘them boys takes their lives in their hands every time they goes to the top. When they fall they’ve got a long ways to drop. Now, us lads that works in the tunnels an’ caissons don’t take no chances like that. There ain’t no place for us to drop. We’re already at the bottom, an’ then some.”’ Paddy laughed at his own joke. There was no doubt of his belief that the sand- hog’s job of sinking caissons and digging tunnels under compressed air was far superior to the risky business of climbing aloft among the beams and girders. “Yes, sir,” he went on, ‘“‘there ain’t no place for a sandhog to fall to, without he lets go of the ladder goin’ down into a caisson, though I mind me of Dan Murphy that was killed by a wooden plug, no bigger than would stop a jug, fallin’ 80 feet an’ hittin’ him on the head when he was at the bottom o’ one o’ the caissons 0’ the Manhattan Bridge, crossin’ the East River, at New York. Them was monsters, them caissons. Ever been down in one, mister?” I pleaded ignorance. Paddy beamed with a superior air. “ES like a big box with a top an’ no bottom, a caisson is,’”- he said. “At the top is the air lock, an’ at the bottom is the muck—earth or sand or gravel or hardpan or rock—whatever stands be- tween the surface of the earth an’ bed- rock. Y’ see, the purpose of the caisson is to clear everything away, down to the backbone o’ the world, so they can have somethin’ solid to rest their steel an’ concrete on. What good would all that be if it wasn’t on rock at the bottom?” He waved his pipe again at the sky- scraper. “Them boys wouldn’t have no jobs at all if it wasn’t that us sandhogs did our job first,”’ he went on. ‘“‘Now it stands to reason that when you get down a certain ways underground you strike water, an’ that ’s why you’ve got to use caissons, unless the bedrock comes above the water line. Ninety-four feet, them Manhattan Bridge caissons went down,

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36 to. set the foundations for the cable towers, an’ 60 feet o’ that was below water line. Sixty foot head o’ water trying to get in through the open bottom of the big box, an’ ‘nothin’ to keep it out but the air they was pumpin’ in from above. Do you know how to figure out what the pressure is at 60 foot?” Again I had to plead ignorance. “I’d have to look in a book for that,” I said, and Paddy smiled his superior smile. N ENGINEER once showed me how,” hesaid. “It’s 4 1/3 pounds for every 10 foot o’ water. What does that come to for 60 foot?” “About 26 pounds to the square inch,”’ I replied. after a moment’s mental calculation. “That’s about it,” said Paddy ap- provingly. ‘“That’s not much—only a six-hour pressure. I’ve worked in lots higher pressures than that, an’ I’d rather do it. The hours are shorter an’ the pay’s higher.” I didn’t understand, ‘and Paddy saw that I didn’t. “They figure out a sandhog’s pay and his working hours accordin’ to the pres- sure he’s got to work under,” he explained. “Up to 18 pounds it’s an eight-hour day an’ eight dollars a day, in tunnel work. That’s two four-hour shifts, with two hours’ rest between ’em. All sandhog jobs are two shifts, for nobody can stand the pressure for a full workin’ day. An’ the higher the pressure, the higher the pay an’ the shorter the day. In caisson work the pay’s a bit higher, and there’s seven kind o’ days, one for pressures up to 18 pounds an’ eight hours’ work; the next is six hours, from 18 to 26 pounds, an’ so on up to pressures above 48 pounds. That’s some pressure! An’ how long do you think a day’s work is under that much air? Half an hour! Two 15- minute shifts, that’s all. But the pay goes up 50 cents a day for every step up in pressure, so a miner—that’s me—gets 31% dollars on top of his eight-fifty, for half an hour’s work. Twelve dollars for 30 minutes! T AIN’T often we have to work under top pressures, though. Deepest job I ever worked on was the Pennsylvania tunnels, from the Jersey shore to the Pennsylvania Railroad terminal in New POPULAR SCIENCE MONTHLY September, 1925 How 30-Foot Tubes a Mile Long York. On that job we got down to 90 feet. That was only about 40 pounds pressure.” Paddy paused and relighted his pipe nonchalantly. Evidently working “under air’ agreed with him. Unlike the struc- tural-steel workers, few of the sandhogs are of the slender, wiry type. They run rather to fat than otherwise, and Paddy Ryan is no exception to the rule. “Sure we get fat, an’ why wouldn’t we?” he responded to my comment. “Man, what an appetite it does give you, workin’ under air! A company doctor explained it to me once. It seems it’s because we inhale more oxygen every time we breathe the compressed air than we do on the surface, an’ it’s the oxygen that burns out the waste in our blood an’ tissues. There must be somethin’ in that, for any kind of a fire burns faster under the air. My pipe, now—three puffs an’ it’s burned out, under 30 pounds pressure. They don’t stand for smokin’ on the job, though. A sandhog that does is blacklisted. In the old days, Pictorial diagram showing how boring opera- tions were carried on in Hudson vehicular tunnels. In the compressed-air chamber be- hind the working face, at extreme left, is an arm that lifts cast-iron segments in place for the tube lining. A safety screen across the upper part of the tube provides means of escape for the sandhogs in case of a blowout before there was electric lights everywhere to work with, an’ wé had to use candles, a candle would burn out in no time. Some- times after a candle was blown out it would light up again from the spark on the wick, just because of the oxygen. “SA? that reminds me of a funny thing,’”’? Paddy went on, after a few reminiscent puffs at his pipe. ‘‘There was a sandhog named Louis Cassari, an Austrian. He was an old-timer, and he held the record for the longest time under air—16 hours, under 30 pounds. Well, Louis blew out his candle in the caisson one day an’ put it in his pocket, an’ you can call me a Dutchman if it didn’t light up again in his pocket. First Louis knew about it was when he felt his leg burnin’, and there was his pants half burned off! “Yes, sir; it’s the oxygen in the com- pressed air that burns up the food we eat, so we have to be sure to eat enough. An’ I suppose it’s the same thing that makes it easy to work under air. Kind o’ likea stimulant; everything’s easy to do. Fellows that are too lazy to shake down the kitchen stove’ll do a big day’s work in a caisson or a tunnel an’ think nothin’ of it. You don’t get tired at all.” “Pretty dangerous work, though, isn’t it?” I ventured. ‘‘Doesn’t it knock a 2; man’s system to pieces, if he keeps it up?” One of the big steel caissons for the vehicular tunnels, towed into position for sinking “You’re thinkin’ about the ‘bends,’ that there used to be so much about in the papers,” replied Paddy. ‘‘Well, it’s the same with this sort o’ work as with any other—a man’s got to take care of him- self. Everybody has to. You have to, don’t you? Well, then, a sandhog that doesn’t take care of himself off the job’ll die sooner than theones that does, but

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pera- cular T be- is an e for as of wout y where idles, a Some- out it ark on xygen, funny > a few “There ari, an and he . under Well, caisson n’ you t light s knew urnin’, ed off! e com- we eat, An’ makes ’ like a o do. > down s work nothin’ 1, isn’t 1ock a it up?” bends,’ | in the t’s the th any f him- 1ve to, g that e job’ll 2s, but September, 1925 POPULAR SCIENCE MONTHLY Were Driven under the Hudson A concrete bulkhead separates the com- pressed-air working chamber from the outside. Through this pass the compressed- air feeder lines, as well as the air lock in which the sandhogs are ‘“‘compressed”’ when they go into the workings and “decom- pressed’’ when they come out. There is alsoa muck lock for passing excavated material there’s nothin’ in workin’ under air to hurt a fellow. Look at me, now. I’ve been workin’, caisson an’ tunnel jobs, on the other side an’ over here, for 30 years, an’ I’m good for 20 years yet. =) ema your time in the air lock, es- pecially comin’ out, an’ don’t let the lock-tender change the pressure too fast, an’ you’re all right. There’s an air lock at the top of the caisson or the shore end of the tunnel. When you go in, they close the door behind you, an’ turn on the air till it gets up to the pressure inside the workin’. Comin’ out, it works the other way. Goin’ in you can take it faster than comin’ out; that’s where the boys used to get into trouble and get the ‘bends,’ comin’ cut of the air too fast. Thirty seconds in the air lock for every pound of pressure is the rule, but some- times a sandhog that’s in too much of a hurry’ll turn the valve when the lock- tender isn’t lookin’. “That’s not much this side o’ murder, for while it might not hurt him, it might kill some o’ the rest o’ the gang in the lock, or cripple ’em for life. That’s when you get the ‘bends’; by comin’ out too fast. It’s like the jumpin’ toothache an’ the worst kind o’ rheumatism com- bined, an’ if it hits you in the head you go daffy. If it gets you in the belly you have the worst colic you ever heard of. There’s only one way to cure it, an’ that’s to go under the air again, and ease off the pressure gradual. It’s little bubbles of air that gets into the blood, under the pressure. They work out through the lungs if you give ’em time.” Paddy’s pipe called for attention again. There was the far-away look in his eyes as he relighted it which told me another reminiscence was coming. “There was a comical thing happened in the Blackwall tunnel, under the Thames, in London, where I done my first work under air,” he said. ‘I was workin’ for Jimmy Sullivan, the best foreman I ever worked under. He was an old-time sandhog, only they call ’em all miners over there. He’d worked in the caissons cf the Forth bridge an’ come over here, once, in 1890, when an English company was tryin’ to run a tunnel under the Hudson, the one McAdoo took hold of afterwards an’ finished—what they call the Hudson Tunnel now. “Well, we had the tunnel through, though the air was still on, 37 pressure began to go down, the whisky- bottle cork blew out with a bang! The compressed air corked up inside of it got to work as soon as the outside pressure got lower than the inside. The cork just skipped one fellow’s nose an’ scared him stiff, but the other bloke was worse scared in a few minutes. Soon as the pressure got down toward zero, all that champagne he had inside of him began to fizz. He was frothin’ at the mouth like a mad dog; an’ talk about your colic! They had to send for a doctor an’ an ambulance to take him home. “ F COURSE,” Paddy went on, with a touch of pride, “‘it ain’t everybody that can stand the air at all. Some gets scared when they hear the roarin’ in their ears when the air comes on in the lock. It’s like goin’ through the Long Island tubes in a train; there’s some never learns how to blow out from inside to equalize the pressure on their eardrums, an’ I’ve heard of men gettin’ their eardrums broke, though I never knew one that did. I knew one lad, though, one of these structural-steel boys, that thought he’d like to be a sandhog. The first time in the air lock he blew so hard he broke a blood-vessel. He was no good. “No, the worst danger is gettin’ pneumonia. You see, it’s hot under the air, an’ you strip down to an undershirt an’ a pair o’ pants. Your blood is all full of oxygen an’ you sweat like a horse. Then you come out of 90 degrees at the end of your shift an’ maybe it’s around zero outside, but you’re so hot you don’t notice it at first, an’ you don’t wrap yourself up like you ought to. Then you get a chill an’—good night!” “But what about the risk of drowning?” I inquired. ‘‘Don’t the caissons and tunnels get flooded, sometimes?” ““A fellow has to take some chances on any job,” replied Paddy; “but it’s no worse on this job than on any other— (Continued on page 125) while we was puttin’ in the lining, when two members of the London County Council thought it would be a nice thing to make a tour of inspection. They were fat, red-faced blokes, retired soapmakers or some- thin’ like that, an’ their idea of an inspection tour was to bring a big hamper of lunch along, with some whisky an’ champagne to wash it down with, an’ eat lunch in the tunnel. : ELL, the air pres- sure was so heavy the champagne cork wouldn’t pop, but had to be pulled out, an’ they were complainin’ about how flat the stuff was. It wouldn’t fizz at all. But they drank it, or one of ’em did. The other stuck to whisky, an’ emptied about half the bottle. Then they went back to the air lock. I was goin’ off shift, so I was in there with ’em. “Pretty soon, as_ the Sandhogs bolting together the great cast-iron segments that form the lining of the great under-river tunnel

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OTN STEM The Speediest of Swimmers Johnny Weismuller is the world’s speediest human swimmer; yet a fish could run circles around him. In his best effort he required 51 2/5 seconds in which to make 100 yards car or rides in one is familiar with the “speed limit’’—the rate beyond which the law says a motor vehicle may not travel. Has Nature, though, also her speed limit? Is there a rate beyond which a human being may not travel without breaking one of Nature’s laws? In other words, could a man operate an airplane or a motor-car at a speed of 1000 miles an hour, say, were science to pro- duce a vehicle capable of going that fast? It is doubtful, says science. The thou- sand-mile-an-hour airplane is mechanical- ly possible, but there are speed limits set up by nature beyond which the human body cannot go. Various physiological proc- esses of the body are the traffic cops that will force man to obey the speed laws of nature, no matter how fast he may build his vehicles, no matter how ambitious he may be to surpass previous speed records. These physiological processes issue un- mistakable warnings in the form of pain, dizziness, nausea, and even unconscious- ness, when man approaches the speed beyond which he may not go. To proceed faster would be suicide. | year of rides who drives a motor- aay SEN Lieut. Al Williams, U.S. N., former big league pitcher, reached the unprecedented speed of 266.59 miles an hour in his airplane, not long ago, he heard the warnings of the traffic cops of nature. “When I rounded a turn,”’ he reported, “T went out cold.” And there, according to science, is the hub of the whole matter. The straight- away speed that man can stand may not yet have been approached; but it is likely that Lieutenant Williams came very close to the rate at which nature will permit a man to speed and turn, POPULAR SCIENCE MONTHLY For in turning there is devel- oped a force called ‘centrifugal force’’—the resistance that a body offers to deflection from its original path. When an airplane turns a corner at a high rate of speed, it “banks.” The pilot is thrown over on his side quite as abruptly as if he were cast from a catapult. The circulation of the blood must adapt itself to the sudden change of position. It is slow to do so. The body is going one way; the blood is circulating in a way that corresponds to quite a different mo- tion of the ,body;'the result is dizziness. Moreover, centrifugal force draws the blood away from the brain. There re- sults a condition known as brain anemia. At 266 miles an hour the brain’s blood supply can readjust itself. At 1000 miles an hour, though, science says, the terrific pull would draw the blood from the brain with such force as to result in permanent injury, possibly death. Major L. H. Bauer, of the School of Aviation Medicine, Mitchel Field, N. Y., September, 1925 Fastest on Two Wheels Jim Davis setting the world’s motorcycle speed record of a mile in 32.53 seconds. The motor- cycle’s possible speed, like the automobile’s, is also limited by the road it has to travel is one scientist who is ready to. predict that excessive speeds will cause perma- nent injury or death. What nature’s speed limit for the hu- man body is, Doctor Bauer says it is impossible to state. But there is a limit, and probably it never will be reached because of nature’s warnings. When Al Williams made 266.59 miles an hour—a mile in a little more than 13 seconds—he traveled faster than a human being ever went before or since. Other aviators have approached that speed, but More than Three Times Faster than Man The racehorse Cherry Pie, which holds the world’s record for a competitive mile, made this distance in 1 minute 35 2/5 seconds. Man’s best record for the same distance afoot is 4 minutes 10 2/5 seconds

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er, 1925 speed 10tor- e’s, is travel predict perma- he hu- s it is . limit, eached ) miles han 13 human Other d, but ance _ Automotive engineers believe that September, 1925 Can YOU (0° New Duscovertes Show that Nature, Not Mechanics, Limits Man’s Speed By Robert E. Martin POPULAR SCIENCE MONTHLY 39 in no other vehicle has anything like such a speed been attained. The closest approach to it, ac- cording to official records, is the mile in 23.07 seconds that Tommy Milton made in his automobile. automobiles never will travel much faster than that. It is not a ques- tion of making a car mechanically capable of attaining the speed; it is a matter of obtaining a road on which such a speed can be negoti- ated with comparative safety. bbw same factor probably limits the possible speed of motor- cycles. Though motorcycles are used by the police in keeping automobile speeders in order, so far as speed records are con- cerned, the motorcycle must take second place to the gutomobile among vehicles that travel the road. For the fastest motorcycle speed recorded is a mile in 32.53 seconds made by Jim Davis. Mechanical vehicles—whether in the air, on the ground, or in the water—make the efforts of man to attain speed through his own muscles seem quite ridiculous. Thus, while man has succeeded in traveling amile in approximately 13 seconds in an airplane and 23 seconds in an auto- mobile, the best time that Paavo Nurmi, the last word in runners, has been able to make for the same distance is con- siderably worsethanfour minutes. Charley Paddock, probably the fastest consistent runner that ever lived, can better Nurmi’s best speed, but only for a short distance. The dizzy speed that has carried this He Came Close to Nature’s Speed Limit When Lieut. Al Williams, U. S. N. (right), reached the un- precedented speed of 266.59 miles an hour in his airplane, he : “went out cold” at a turn—evidence of nature’s speed limit slower his pace must become His Car Traveled a Mile in 23.07 Seconds The nearest approach to the fastest airplane speed is the mile in 23.07 seconds, made by Tommy Milton (above) in his automobile. Automotive engineers believe that automobiles never will travel much faster than this record. This remarkable picture shows Milton’s car traveling at top speed The Greatest Sprinter Charley Paddock, probably the fastest runner that ever lived, has traveled 100 yards in 9 3/5 seconds; yet he could not maintain such speed, for the farther man goes, the California athlete 100 yards in 9 3/5 seconds cannot be maintained by him for a mile—or even for an eighth of a mile, for the farther man goes, the slower he goes. In the water, man’s speed depends en- tirely on his method of navigation. Ina motor-boat he can reach express-train speed. The speed of the greatest swim- mer, however, cannot be compared with the speed of the average walker. Thus Johnny Weismuller, who has eclipsed all records at the shorter distances, required 51 2/5 seconds to make 100 yards in his best effort. A fish, of course, could circle round and round this greatest of swimmers and beat him at any distance. Similarly, most animals can eclipse the best speed of which man is capable afoot. Thus, Cherry Pie, the racehorse, which holds the world’s record for a competitive mile, accomplished the distance in 1 minute 35 2/5 seconds. Nurmi’s best record for the same distance is 4 minutes 10 2/5 seconds. With some mechanical aid, man can better that latter time. Thus, Reggie McNamara has gone a mile in 1 minute 45,seconds on a bicycle, while Arthur Staff has. made a mile in 2 minutes 35 seconds on ice skates. There seem to be very definite limits, though, to what man can accomplish with his muscles. Only a small fraction of a second usually separates the new record from the old.

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interes att a RST ELSE ae POPULAR SCIENCE MONTHLY September, 1935 One of the new gliders soaring over the sea after hms start down a hillside against the wind Sea Gliders—the Last Word in Aircraft The pictures on this page pret an = : were taken during a re- cent German contest for new types of motorless gliders capable of sus- tained flight and of alighting on the water. The picture at the left shows a biplane glider wrecked on the beach after the pilot had at- tempted a sea landing \ Two contesting gliders in the air. The one at the left flew for eight continuous hours before landing Above: A glider skim- ming the water’s sur- face in making a perfect descent. At the right: How the contesting ma- chines were hauled to the scene of competi- he Espeniaud 3 tion by teams of horses. : i Note the absence of landing gear and the t a ‘ | fishlike body of the | *: a oe & 3: acl sem me sp ge esis isan s ee or. glider, a monoplane — all us Septe

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> 1925 1¢€ air. eight nding September, 1925 Poisons that Lurk in “Bootleg Booze” Federal Chemists Reveal the Perils of ‘“‘Imported’’ and Homemade Liquors By Norman C. McLoud as foul as bootleg liquor, and the population will be in a state of complete panic. In this circumstance lies one of life’s mysteries. Civilization balks at drinking polluted water. The mere suggestion of impurity brings consternation and dis- may. A hint of typhoid germs in the water supply will terrify an _ entire community. Bootleg liquor, though, is a different proposition. Ninety-nine per cent of the stuff is off color. Much of it is the sort that kills. Not more than one quart in a hundred meets the standards of the days preceding prohibition. More than that, much of it contains actual, active poisons, among them carbolic acid, for- maldehyde, pyridine, acetone, and iodine —chemicals that are used in denaturing the aleohol from which much of the bootleg stuff is fabricated and which the bootleg manufacturer cannot remove when attempting to turn the denatured alcohol into a beverage. Lye is another poison that is found in bootleg booze. Lead salts, zinc salts, and tin salts, absorbed either from the distilling apparatus or from the containers in which the stuff is shipped, frequently appear in the weird liquors that are sold for genuine Scotch, rye, or gin. And in spite of all this the public drinks the stuff and pays fancy Ss the national water supply become POPULAR SCIENCE MONTHLY prices for the privilege. This is not propaganda. The statements are cold facts, stripped of argument, and based on scientific re- search. They are the product ofapplied chemistry seeking the truth about the national liquor supply. They are facts unbiased by personal opinion on the prohibition question. There is a government laboratory in Washington that devotes itself to the job of learning what’s in bootleg booze. I have lived with the chemists in this laboratory. I have seen them taste “bootleg’’—as a part of their day’s work— and spit it out as they would the rankest poison. In the process of observation I have seen them cheat death by seconds through the simple expedient of getting rid of the stuff before it could get them. “We learn to taste without swallow- ing,’”’ government chemists explained to me. ‘Chemical analysis is exact, but Spirits? When poured from a bottle, this alleged “whisky” was pure am- ber, apparently a safe beverage. The addi- tion of water, though, turned it a cloudy white, due to the pres- ence of a poisonous denaturing agent The Label Says ‘‘Scotch”’ J. R. Young, government liquor tester for the last five years, is shown here examining a sample from a bottle bearing the label of a familiar brand of “Scotch.” Analysis proved it to be poisonous 41 *“‘Less than One Per Cent Is Genuine” Dr. W. V. Linder, chief of the Chemical Section, U.S. Internal Revenue Bureau, examining typical specimens of moonshine. In the last year Dr. Linder and his chemists have analyzed more than 85,000 samples of bootleg liquor. ‘‘Less than one per cent of the stuff now sold,” he says, “is genuine liquor” there are some questions that it does not answer. The sense of taste must be employed also. We can taste the con- tents of 25 or 30 bottles without swallow- ing a drop. If we did swallow it, there would be daily vacancies on the payroll.” In my study of contraband booze I have enjoyed contact with Dr. W. V. Linder, chief of the Chemical Section of the Internal Revenue Bureau. In the last year Doctor Linder and his chemists have analyzed more than 85,000 samples of bootleg liquor. “TESS than one per cent of the stuff now sold,” Linder told me, “‘is genuine liquor. Despite all you hear on the coasts about liquor that is ‘just off a ship,’ or in other parts of the country about liquor that has ‘just been smuggled across the border,’ or ‘fraudulently with- drawn from a bonded warehouse,’ boot- leggers simply can’t get hold of the ‘real stuff.’ The supply today is made up of moonshine, distilled under the most filthy and insanitary conditions imagi- nable, or mixtures of denatured alcohol, colored and flavored to represent whisky, or containing juniper to make it pass as gin. That this stuff is not as pure as before must be conceded. “Poison? Of course. The degree of poison varies, but it is there just the same. Some of the stuff kills immediately. We have had gallons and gallons here, one drink of which might have meant death. Other mixtures might be drunk regularly for months perhaps before the poisons became effective. Sooner or later, though, they would become effective, “The death certificate of the drinker might not show bootleg liquor as the cause of death, but it would be the

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ae enn mens SPEEA GE TE e TEES le te UA SO ae SoA I SRR 42 cause nevertheless. For the effects of many of these poisons are cumulative. They attack the liver or kidneys; under- mine the entire system. “Tt has been claimed that bootleg liquor is no more harmful in this respect than the alcoholic beverages consumed in other days. This contention, though, is wrong. The baneful effects of the pres- ent type of liquor are far greater.” Linder has a staunch ally in the offi- cial person of J. M. Doran, head ofthe Prohibition Unit’s Industrial POPULAR SCIENCE MONTHLY exact counterparts of the bottles that designated various brands before liquor became an outlaw. Dressing the bottles received the same careful attention at the hands of this enterprising dealer. His counterfeits in- cluded labels, tinfoil, stoppers, and everything that might be required for giving the bottle an honest appearance. Even the packing was not overlooked. The supplies embraced the peculiar Scottish nails used overseas for fastening September, 1925 Not long ago a rum ship was capt which contained a complete outfit for fabricating ‘“‘Scotch” of almost any de. sired brand—There were alcohol, flayop. ing chemicals, bottles, labels, corks cases; everything that was required give the appearance of genuineness to the ship-made liquor. From at least two points—one in New Jersey and the other on Long Island—bootleg “Scotch” made on United States soil, I am told, is transported regularly to the rum fleet h Alcohol and Chemical Division, Doran backs the statements of the chemical chief and makes startling declarations of hisown. re UCH of the whisky, gin, IVE and kindred drinks peddled by bootleggers,’’ this expert told me, “‘have as their basis either moonshine, with its attendant poisons, or dena- tured alcohol, a non-beverage liquor intended for industrial use. The latter consists of pure grain alcohol to which has been added various de- naturants rendering it unfit for beverage purposes. “These denaturants are im- possible of elimination by any process employed by the boot- legger. The majority of cases of instant death from alcoholic poisoning are the results of drinking this class of concoc- tion. “Wood alcohol produces paralysis and atrophy of the optic nerve, with total blindness, inflammation of the kidneys and bladder, nephritis, and cystitis In some cases it produces death. It is known that death has been caused by as little as three ounces. Detection of the presence of wood alcohol is im- possible except by thorough analysis performed by a skilled chemist in a well- equipped laboratory. “This product is diluted, flavored, and colored, bottled in containers bearing fake caps, labels, and stamps, and sold as well known brands of liquor.” N THIS last statement is found the tack that punctures the consumer’s bubble of security produced by familiar labels. Nobody should let himself be fooled by an honest appearance on the outside of the bottle: Counterfeit pack- ages are the essence of the bootlegger’s trade. “Almost every brand of label has been imitated,” Doran told me. “Whether domestic or foreign, the labels have been made and sold by the tens of thousands. Few labels known to Ameri- can consumers have been overlooked.” One source of supply for fake materials was discovered in the shadow of the United States Capitol. In this establish- ment the representatives of the Treasury Department found a stock of merchan- dise that constituted a bootlegger’s de- light. There could be obtained any de- sired variety of bottle he might require— In the Storehouse of Fakes J. W. Quillen, Uncle Sam’s thief chemist in the New York laboratory, with part of his huge store of bottles. Many of these bottles bear familiar labels. Almost all of them, however, contain fake “‘booze,”” most of which is poisonous or unfit to drink the cases. in which Scotch whisky is packed for export. Straw wrappings were also on hand. The man who could see this merchandise and retain his faith in labels and appearances would be the world’s champion dupe. Even were you to see your “Scotch” come off a Rum Row ship, the govern- ment experts inform me, you have no guarantee that the stuff ever saw Scotland —or any other place beyond the famous three-mile limit. For the bootleggers have discovered that it is much easier and cheaper to manufacture their own “imported” liquor and then go through the motions of carrying it ashore from Rum Row than to handle the genuine stuff from abroad. motorboat and carried back again by the rum-runners and disposed of as imported stuf ve bootlegger is a goog advertiser. Much of his prosperity arises from stories sent broadcast regarding the large amount of liquor being smuggled into the United States, and similar stories of large amounts fraudulently withdrawn from bonded ware. houses. These stories, though, Linder, Doran, and Roy 4, Haynes, Federal Prohibition Commissioner, assured me, were made of thesame material that supplies the body of much of the liquor that is peddled these days—moonshine. “It is almost impossible to get real liquor,” said Doran, “Even though it may have been real once, it does not re main that way for more than a few hours after coming into the possession of the boot legger, for the bootlegger is not going to lose fabulous profits by selling good liquor ‘as is’ when he can dilute or ‘cut’ it with rm distilled denatured alcohol, wood alcohol, or coloring matter, and make of it four or five times the original amount.” The possibility of getting “real stuff’ from bonded warehouses, Prohibition Commissioner Haynes told me, no longer exists. All bonded stocks now are con centrated in a few centrally located ware houses to prevent leakage. Seven-eighths of the supply now is held in 30 con centration warehouses. Since this store was formerly held in 296 outlying places, the possibility of robbery or withdrawal by other fraudulent means has become negligible. yw it comes to a question of “‘moonshine’”’ the chemist has many fresh thrills. His schedule of what's what in contraband liquor now embraces the field of natural history as well as the catalog of poisons. Snakes, lizards, rats, and bugs are some of the mildest of these ingredients. Actual poisons are among the most vicious. Between these classifications come many things varyingly repulsive. “‘A serious problem is presented by the use’ of liquors distilled locally and at home,” says Doran. “Alarmed by the recorded and published effects of wood- alcohol mixtures, a large element of the (Continued on page 132) rs aortas @ ee

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ber, 1925 apt utfit for any de. a flavor. » Cor uired to eness to one jn m Long n. United Pie eet ed be ners and ‘ed stuff, & good 1 of his 1 stories ding the or being United tories of dulently led Ware- , though, Roy A. ohibition red me, : material r of much peddled ne. ssible to 1 Doran, lay have *S not re- 1ore than ning into he boot- tlegger is fabulous ; good n he can with re 1 alcohol, coloring ke of it mes __ the of getting n bonded hibition no longer are con ited ware- on-eighths . 830 con- this store ng places, ithdrawal s become iestion of has many of what's embraces rell as the bugs are gredients. the most sifications repulsive. ed by the y and at d by the of wood- nt of the September, 1925 POPULAR SCIENCE MONTHLY . 43 Shoe-Leather from the Sharks Remarkable Fish-Hide Industry te Developed by New Process | HE increasing scardity of mammal hides in recent | years has caused leather manufacturers to turn to the sea for their raw product. through experiments under the direction of the U. S. Bureau of Fisheries, the skins of sharks, porpoises, and other fish have been developed into excellent leather. For this purpose shark fisheries have been established on the Florida and Gulf coasts, and new industries are being established to utilize the new product. This has been made possible largely by a process of tanning developed in the laboratory of Dr. Allen Rogers in the Pratt Institute of Brooklyn, N. Y., and pictured on this page. One company, it is reported, now is turning out 200 shark hides daily. The hides are made into high grade waterproof leather that can be used just as ordinary leather. ‘There is said to be as much leather value in a shark as in a cow, and the cost of a fish is far less. Today, largely One Haul of Sharks Special tarred nets, 600 yards long, with four- inch barred mesh, are usedtocatchthe sharks. With this apparatus from 50 to 200 sharks are taken daily Perfects New Tanning Process Dr. Allen Rogers of Brooklyn, N. Y., discoverer of a new process for making commercial leather from shark skins, in his laboratory testing the finished leather The Polisher Washing the Fish Hides In the new tanning process the shark skins are soaked for 24 hours, then washed thoroughly in large vats, as shown above. After this, they are left in a weak solution of caustic soda or lime for two days, being stirred occasionally, and finally they are washed a second time After the skins are treated and dried, they are shaved on the grain side to remove coarse projections or den- ticles. Then, with the ma- chine shown above, they are polished on a rapidly movingcarborundum wheel Softening Hides On the machine at the left the hides are made pliable. Some of them are given a gun-metal finish suitable for shoes. Others are tanned for lin- ing leather and cordovan

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Seed ries ata aaeesenrenran. SM hayes AE FROM, POPULAR SCIENCE MONTHLY September, 1995 IKE a wild-animai train. er, i a cage full of potential death, “Slim” Hoffman makes high explos. ives obey his commands, His is the most dang job on the movie “fot.” Upon his skill often de. pend the lives of hyp. dreds of actors. “Phe only trick,” he says, ‘%. knowing what your ex. plosive will do, then tig. ing the mixture with the action of players gy that of the camera” € H Staged M How “Slim” Hoffman Makes Dynamite Do Astonishing Tricks for Movie Thrillers By Fred Gilman Jopp BLINDING flash lights up the inky horizon. Another! The shriek of shells with stunning crash of detonation. The numb earth throbs. Flames! Destruction! Horror! The deathly silence that follows is broken only by the grinding click of cameras striving to catch the last thin wisp of smoke. The movie battle is over. Not long ago a big freighter, formerly the S. S. Corvallis, sailed serenely off the coast of Sandy Hook. A man watched over a switchboard. He pressed a key. Half an hour elapsed, as the movie cap- tions say, and floating bits of debris were the only token of the vessel that had been shattered and sunk. Ten tons of dyna- mite and 1000 pounds of gunpowder had done their work. All to provide a mo- ment’s thrill for you some night at the movies! Has ore Battles than Napoleon One man blows up a huge steamship. A single man creates the carnage of a whole battle—in the movies. He is a powerful person and important. for he plays with the most dangerous tools on the “lot.” On his skill often depend the lives of hundreds of actors. Here is the time to introduce Walter J. (“Slim’’) Hoffman, screenland’s explosive engineer, the man who has staged more battles than Napoleon, but who differs from the Little Corporal in that he has yet to cause his first casualty. Hoffman can make dynamite do a whole bagful of tricks. Blowing Up a Steamship for a Thrill Ten tons of dynamite and 1000 pounds of gunpowder—set off by one man with the press- ing of a key—produced this spectacular explosion of the steamship Corvallis a few weeks ago off Sandy Hook. And all to provide a moment’s thrill for you in the movies Everything has changed in motion- picture production, including methods of destruction. Movie sets used to be razed by pulling wires or cutting ropes. This never was satisfactory, because human beings all react differently. The pull on wires or the chopping of ropes never was uniform, and time after time a building would fall halfway and then stop in mid- air because some rope or wire had caught on a projection. Then the method of using fuses came in. While this was an improvement, still it was unsatisfactory, because fuses

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1€ press- w weeks movies | motion- ethods of > be razed ves. This se human 1e pull on never was 1 building yp in mid- ad caught ises came ment, still use fuses September, 1925 POPULAR SCIENCE MONTHLY 45 Ne A Movie Bombardment of a French Village Shell, shrapnel, and other gunfire are produced with remarkable realism by the explosive engineer through skilful blending of his powder mixtures would go out at the wrong time. Often when a whole building was to be razed, one portion of it would remain standing because the explosive failed to explode. Accidents occurred from delayed fuses, causing serious injuries in some cases. Today explosions are created by elec- tricity and powder. All parts of a build- ing can be destroyed simultaneously, or any portion of it without disturbing the rest. Or explosions can be timed to act consecutively, giving film effects that By ingenious placing of explosives, any part of a building can be destroyed without disturbing the rest. Behind the camera sits man, watching for the exact moment to throw the switch that will “shoot” anexplosion wherea moment before stood an actor startle. So long as the powder is of a cer- tain chemical quality a certain mechanical result is assured. There are no chances of accidents under these modern conditions. The explosive engineer must construct a Civil War or a modern battle at three days’ notice. The problems that greet him each day would drive another engi- neer crazy. An idea of what he is up against may be gleaned from the follow- ing assignments. The list is typical of the jobs “Slim” Hoffman finds waiting for him when he comes down to the lot in the morning. 1. Destroy the brick laboratory on the back lot without harming the two glass stages 100 feet dis- tant. 2. Anexplosionin which a trick cigar explodes in the villain’s mouth to blind him, and at the same time shatters the glass of poi- soned wine held by the aged father. 3. A projectile breaking through one wall, must travel between two actors and out the other wall. 4. A man off balance, about to fall down a man- hole, must be set back on his feet by the concussion of an explosion set off below. No tricks. 5. Destroy an_ entire French village with ex- plosions that give the ef- fect of shrapnel fire. This is a good begin- ning. difficult problems are locked away in the All the secrets of solving these explosive engineer’s brain. really nothing to them,” Hoffman told me with a laugh. “The only trick is knowing exactly what your explosive will do, then timing the mixture with the action of players and camera. “There is i: HE great difficulty is with the human element. Powder will do what I command, but the players sometimes won’t, and the result is grief, and lots of it. Actors, like almost all other people, have difficulty in mastering the psychol- ogy of fear. Any one can walk 20 feet on a curbstone, but lift that curb 100 feet in the air, and it’s a different story. “Tt is the same way with explosions. We can point out that the explosion will affect only a certain area, that physically it can spread no farther, but reasoning does no good when an actor is afraid. Usually, in such cases, the director and I get around things by keeping the ex- plosion a secret. In this way:I can guarantee positive results, and the di- rector obtains registration of honest-to- goodness emotion. Imagine your favorite star standing near a couple of sticks of dynamite, and that dynamite explod- ing without her knowledge! Does she register fear and amazement? I'll say she does! “The wise director, however, shoots the explosive scene at the very end of the picture, because after the explosion the star is likely to be a little shaky. And you can’t blame her. But when this picture is shown and the critics rave over the star’s great emotional work, you can (Continued on page 133)

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= Lae Se eee eee PI 88 8 ae Soe a PNT TEENY AR POPULAR SCIENCE MONTHLY Drift-Recorder Keeps Pilots on Course An Ingenious New Aid to Aviators VIATORS throughout the world A are interested in recent successful tests of an instrument, invented by Commander Le Prieur of the French Army Aviation Service, that enables pilots to determine exactly the deviation of their craft from its course as the result of side winds. This instrument, called the ‘‘navi- graph,” makes it possible for the pilot to reach his objective in the shortest time possible. The principle of the navigraph is ex- plained in the accompanying diagram. Supposing an airplane should start from A on a course A X, with the intention of © reaching B. If it % Z were exposed dur- H f ing its flight to a B / — side wind blowing in the direction ‘s BC the airplane would find itself at the end of a calcu- lated time at C, having actually traveled along the drift line AZ, though pointed in a direction parallel TRUE COURSE hour of the air- plane. The vec- tor BC represents the speed and direction of the wind in miles an hour, and_ the vector AC repre- sents the course actually followed by the airplane and its speed an hour in relation to the ground. The angle BAC represents the de- viation due to the wind. Knowing the speed of his air- plane and the direction and dis- tance of his objective, the aviator needs only to know the angle and direction of his drift to enable him to lay out a course that will un- erringly take him to his destina- tion within a calculable time. The object of Le Prieur’s navi- graph is to provide a simple method of determining the drift angle. The navigraph consists of an instrument for determining the direction and angle of side drift, Commander Le Prieur using his new drift-recording in- strument. While he sights through the small telescope, keep- ing some object on earth in the center of vision, the angle of drift is recorded auto- matically by the mechanism at right September, 1935 ANGLE OF DRIFT How an_ airplane, blown by a side wind, is carried from its true course AB along the drift line AC to AB. If we assume that the airplane, flying in still air, would have cov- ered the distance AB in one hour, the line AB in the triangle would rep- resent the speed an and an apparatus for plotting corrections of the line of flight. A small movable telescope is mounted to form one side of an articulated parallelogram. The other side is formed by a tube with a pencil at oneend. The axes of the pencil tube and the telescope always remain parallel. The point rests on a recording paper stretched between two rollers. To determine the angle of drift, the aviator sights through the telescope some distant point along the line of flight. By keeping that point in the center of the field of the telescope, and drawing a line along the edge of the calibrated ruler mounted on a disk in a parallel position, the aviator will obtain a pencil-line record indictating the angle of drift. French Air-Propelled Sea-Sleds Race a Mile a Minute mounted While high power motor-boats have been matching their speed against express trains in the United States, a remarkable new type of racing craft, driven by airplane propeller, has appeared on the Seine River in France. It is called a ‘‘ sea-sled.”” A number of these boats, racing under the auspices of the Motor-Boat Club of France, are reported to have attained the remarkable speed of a mile-a-minute Below is a front view of the sea-sled speeding across the waves. left shows how the motor and propeller are The close-up view at the securely on a framework above the stern deck of the flat, streamlined craft § i ( t ] 1 1 ]

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mber, 19235 ope some ght. By er of the ng a line ted ruler position, ne record speeding -w at the eller are k above ned craft September, 1925 Dr. Byron E. Eldred demonstrating his re- markable new vibrating instrument for the deaf WO highly ingenious devices for the relief of the deaf recently have been developed by scientists. Dr. Byron E. Eldred, mechanical engi- neer, of New York City, is responsible for the apparatus pictured above. The ope- ration of this is based on the fact that deaf persons often can hear sounds ordi- narily inaudible to them when the sounds are accompanied by loud noises, such as the rumbling of a train, or the beating ofa drum. This phenomenon, scientists be- lieve, is due to the fact that vibrations of the louder noises act as a sort of “‘carrier wave” for the smaller voice vibrations. Doctor Eldred’s device, by means of two generators that actuate a diaphragm, sends out a succession of air vibrations, corresponding to the rumble of a train or similar noises,and these are said to aid deaf persons to hear ordinary conversation. POPULAR SCIENCE MONTHLY Another device to aid the deaf is a miniature telephone receiver developed by engi- neers of the Bell Telephone Laboratories. This fits into the ear, and is vir- tually invisible. With its connecting cord it weighs only six-tenths of an ounce. It is connected New Aids for the Dend Compact Amplifiers Replace Kar Trumpet with a microphone that can be worn in the coat lapel, and an amplifier in a box that can be carried in the hand. The am- plifier contains two small vacuum tubes and the necessary batteries. By the use of this device, which is called the “audi- phone,” a person who has lost 60 per cent of his hearing is said to be able to hear the ordinary conversational tones of a speaker three feet away. How the miniature telephone, called the “‘audiphone,”’ instrument is so small that it fits in a person’s ear. is used by a deaf person. The The amplifier is seen on the chair Automatic Wireless Instrument Sends “SOS” Calls at Sea may have a chance for his life with the rest of crew if the vessel should sink, a new SOS sending device has been invented to give automatically the ship’s call sign, the latitude and longitude, and the distress signal. After the machine has started it will continue sending out the call until the ship sinks, according to the inventor, M. Passaquin, a young French engineer. No operator is needed. Dials on the "Taw the radio operator of a ship machine may be set each day according to the ship’s location so that everything may be ready in case of accident. The instrument, operated by a small electric motor, is contained in a cabinet and may be mounted on a table. It con- The control panel of the automatic SOS transmitter, with dials for the various settings, is shown above. Notches on the rim of the revolving wheel shown at left transmit the dots and dashes of the signal. At the right is an automatic receiving instrument sists of a wheel with notches all around its rim and a shaft bearing 14 cams. The notches on the rim of the wheel transmit the three dots, three dashes, and three dots of the SOS signal. These are sent three times in succession, and then fol- lows a long space that allows for the send- ing of the ship’s call sign. The latitude and longitude are then sent by the cam arrangement, which has 14 cams, 10 for digits and four for compass points. The control panel is arranged with dials for the various settings. Seacraft equipped with this invention does not need radio operators on board in order to send out messages of distress.

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48 Sun-Gazer Forecasts Weather POPULAR SCIENCE MONTHLY World’s Most Powerful Magnet For use in testing the atomic theory in metals, this huge magnet, said to be the most powerful in the world, was installed recently in the Engineering School of the University of California at Berkeley LMOST every day of the month A there are produced new inventions or discoveries to lighten human labor, relieve suffering, add to our com- fort, or increase our knowledge of the world we live in. Are you keeping in touch with them? Do you know of their value to you? The following brief survey of the month’s important achievements will help you keep up to date in the rapid progress of science and invention. The Sun as an Almanac NCE every day for more than a year Henry H. Clayton, meteorologist, formerly official forecaster in Argentina, has been looking at the sun through a telescope, and forecasting, from what he has seen there, the temperature of the day one week following, in New York City. He mails his predictions to the Smith- sonian Institution in Washington the day he makes them. Recently, in checking up his method of forecasting weather by the sun, Smith- sonian computers announced that for the year Clayton’s predictions, on the aver- age, worked out remarkably well. Bright patches on the sun, called “faculae,”’ or numerous sun-spots, mean that a hotter sun is coming, Clayton explains. An in- crease of solar heating, contrary to what one might expect, means cooler weather in the East. The methods of forecasting now em- ployed by the U. S. Weather Bureau produce only general predictions of the “fair and warmer’’ type. Antiseptic Rays Purify Water WO scientists in Paris recently dropped a bottle containing an anti- septic in a vessel of impure water. The bottle was tightly corked so that its The Biggest Airplane Propeller Measuring 16 feet across, this immense airplane propeller was constructed recently in Milwaukee, Wis., for one of the planes that soen will attempt a round-the-world flight from Seattle. It is declared to be the largest aircraft propeller ever built, and is designed to travel 1200 revolutions a minute contents could not come in contact with the water. Yet 24 hours later, when the bottle was taken out, 25 per cent of the microbes in the water had been killed. The account of this amazing experi- ment conducted by Doctors Techouéyres and Bunau-Varilla was made recently before the French Academy of Sciences. An explanation advanced is that the anti- septic gives off rays that attack microbes, just as ultra-violet rays do. The tube that contained the antiseptic, a weak solution of chloride of lime, was made of quartz, which apparently let the rays through readily. Out of 60 tests, 51 showed that the microbe colonies had been reduced nearly 30 per cent after 24 hours’ exposure to the antiseptic, without contact. The conse- quences of this experiment may {be of Other New Discoveries and Useful Inventions that Mark the W orld’; Achievements in Science September, 1935 great importance for hygiene and medi cine. Our city drinking water, fy example, in the future may be purified at very low cost without chemicals. Survey Crops by Airplane AGRICULTURAL observers are try. ing out the plan of going up in ai. planes to determine crop conditions. fy a test flight recently, an army plane flew over a 200-mile area in North Caroling covered with tobacco, peaches, and other important crops. At a height of from 50 to 200 feet an agricultural statistician was able to note the extent of damage done by insects or storms. Further, he was able to deter. mine by the color of the crops and soil the general healthiness of the crops, In an airplane an esti- mate of crop conditions ' over a large area can be made in a single day, it is said, while by the old method of sending out question. naires to farmers, it often takes 10 days to get the information. Boosting Aeronautics HALF a million dollars has been given by Daniel Guggenheim to establish the first School of Aeronautics in the United States. It will be a part of New York University in New York City. A $24,000 prize is being offered in Eng- land for the design of a moderate priced, low powered, light airplane for popular use. It must be a two-seater, dual control plane of British construction, with folding wings and an engine that weighs not more than 170 pounds. Coffee and Alcohol OFFEE is more of a stimulant than alcohol. The latter makes a man stupid. Itis depressing and paralyzes all proper fear and restraint. While those under its influence can do more work, they do not do it well. On the other hand, coffee is stimulating, enabling a user to work beyond normal strength, al- though he must pay the penalty later in loss of sleep. These statements were made by Dean Henry H. Rusby, of the Columbia College of Pharmacy in New York City, explaining why the world drinks what it does. Another Columbia University professor, Dr. H. L. Hollingworth, put six college students to a two weeks’ drinking test to find an answer to the question: When is a man intoxicated? In courts all sorts ‘of tests are used, from making a man Septe walk alph Al dent: their versé attit resul Holli tests into? ness, the s tapPp

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mber, 1935 -T res Ons lds nce nd medi. ater, for urified at * lane are try. up in air. ions. fy lane flew Caroling and other 0 feet an e€ to note insects or to deter. lor of the 1e general he crops, e an esti- onditions 2a can be while by question- 10 days cS en given establish s in the t of New Sity. 1 in Eng- e priced, popular r, dual ion, with it weighs ant than ; a man alyzes all ile those re work, he other abling a ngth, al- r later in its were y, of the in New 1e world yr ofessor, x college ig test to : When ; all sorts 7 a man ". germ of September, 1925 walk a chalk line to repeating the alphabet backward. Alcohol was included in the stu- dents’ diet on certain days without their knowledge, and their con- versation, conduct, appearance, and attitude were observed carefully. The results showed, according to Doctor Hollingworth, that psychological tests are the best method of detecting intoxication. These measure steadi- ness, speed, and control by testing the subject’s ability in such things as tapping with a pencil and adding. Catfish Lives 50 Years OW long does a fish live? Not H out of water. Any boy can tell that from observation. But with proper food—everything it needs? Major F. S. Fowler, of England, who has been conducting a special study to find out, reports that a cat- fish with which he is acquainted is now 50 years old and is still lively. An electric eel in the London Zoo, he found, lived'12 years. Other fish age figures, as given by Major Fowler, are as follows: carp, 13 years; goldfish, 12 years; herring, four years; salmon, three years; brown trout, six years. A bull- frog’s recorded age was 15 years; toad, 11 years, and the giant salamander, 52 years. Lung Capacity and Health purr out your chest, but don’t be too proud of yourself. Large lung ca- pacity does not mean, necessarily, that you are healthy. Dr. J. A. Meyers, of the University of Minnesota Medical School, reporting the results of six years of study of lung capacity, says that it is by no means a certain test. The man with the To find a way of preserving marble in its original beauty, the U. S. Bureau of Standards recently installed this testing machine, which subjects samples of marble tiling to vigorous D. W. Kessler, in charge of the laboratory, is seen holding a piece of the ’ POPULAR SCIENCE MONTHLY scrubbing with various cleaning fluids. 49 can be found of house flies, stable flies, or blue-bottle flies. There is no evidence that the monster beasts roaming over Colorado in prehistoric days, were both- ered by these pests. U. S. Indian Population Gains 22 Per Cent HE “‘poor Indian” is holding his own in the United States. Instead of dying out, as is popularly believed, the Pueblos and other tribes are increasing at a rate nearly as high as that of the white population. A census just taken shows that in the last 10 years the population of Pueblo vil- lages increased more than 22 per cent. During that same time the entire population of the United States increased 39 per cent, and part of that was due to immigration. Dr. Edgar L. Hewett, a well known archeologist, who has been studying the In- dians, denies that disease is appallingly prevalent. ‘‘Banana Myth”’ Refuted marble in his hand after it had been cleaned in this way been found in Colorado. Fortunately, they are dead and have been so for one or two million years. They are fossils, found recently in rock deposits near the foot of Pike’s Peak by expeditions under T. D. Cockerell of the University of Colorado. Strangely enough, not a trace HEN Columbus arrived in America, there were no bananas here. They were introduced 24 years later from the Canary Islands. Early migrants carried them to the Pacifie Islands, but they first grew in the Malay Archipelago on the other side of the world. Doctor W. E. Safford, economic bota- anist of the U. S. Department of Agri- barrel chest may have done hard la- bor, engaged active- Him a Fortune culture, made these statements recently Hate of Noise Won ly in athletics, or sung baritone in the choir. Any of these things would have increased his lung capacity. At the same time his lungs may be diseased. Many persons who were known to have 125 per cent or more of normal lung capacity, Doctor Meyers’ study re- vealed, developed diseases of the heart or lungs. Later ex- amination showed the disease decreased the lung capacity of the individual, while it still left him with more than 100 per cent, or normal, capacity. Insects of Past Ages SETSE flies, jnatennsttonsen carriers of the ‘ sleeping sickness, fatal to Alden L. Putnam, of Lansing, Mich., inventor of the popular balloon tire ECAUSE he hated noise, he pat- ented one of the world’s richest inventions. Alden L. Putnam, of Lansing, Mich., invented balloon tires to stop the chatter of his car. Reared in the peaceful New Eng- land countryside, he enjoyed quiet instinctively. And so later, when he drove his car over railway tracks or uneven roads near Detroit, the rattle of the machine irritated him. As superintendent of an automobile fac- tory he did his best to quiet the noises of cars turned out of the plant. During the war Mr. Putnam served with the U. S. Motor Transport. The noise of the heavy army cars exasperated him. Finally, one day, he gave a tire a spiteful kick. It replied with a loud thump. The inventor rushed back to his garage. He had discovered the source of road noise. He put huge tires on the wheels of his car—34 by 7 inches. The rims were not made for these, and the tires were ruined. He tried another set, and persisted until he had perfected his big tire. Mr. Putnam applied for a patent on his balloon tires in 1920, but it was granted only this year. Within the last 18 months balloon tires have become standard equipment, and from his passion for quiet it is pre- dicted the inventor will reap a for- tune. men and cattle, have in refuting what he calls the great ‘‘ba- nana myth.” That is, that bananas originated .in this hemisphere and were cultivated here in prehistoric times by the Indians. New Method of ‘*Painting”’ on AINTING’”’ buildings with light is an inexpen- sive and effective method invented by engineers in Fresno, Calif. The walls are made of cream-~ tinted terra cotta or pressed brick and flood-lighted with colors such as soft magenta, ruby, or emerald. Wonderful ‘“‘dream pictures’”’ are said to result. Ancient Bread [CAVES of bread 2000 years old were dug up recently in Egypt.

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ean sco = Be Pate Be ee BaF RSS Ingenious Revolving Eraser Holds Paper Cutter OR draftsmen, architects, builders, typists, and others who have occasion to make frequent erasures, sometimes from important papers, a new type of revolving eraser has been invented by James F. Hayes of Chicago. Pressing the thumb on a plunger produces an erasing surface of more than four inches. An attachment to the eraser sharpens pencils, opens envelopes, cuts paper, and erases ink. Chance Leads to Valuable Find in Tire-Repairing | Foe NESTLER, of New York City, bought a new car that had gone through a fire. The tires, as well as the body of the car, were somewhat damaged by fire and in attempting to repair these burned tires, Mr. Nestler had a curious experience. One of the five tires gave re- markable results after he had retreaded it, but the others suffered from the loose treads that so often end the usefulness cf retreaded tires. In experimenting to find out why the one tire should lend itself so readily to a retreading job, Mr. Nestier stumbled on a process for retreading tires that appears to eliminate the. many defects in former processes. The chief trouble always has been the difficulty in keeping the new tread from parting company with the carcass of the tire. By Nestler’s process the surface of the old rubber is reduced to unvulcanized rubber so that when the new tread is applied and the tire revul- canized, the new rubber fuses with the old and a perfect bond is formed. The inventor, Emil Nest- ler, demonstratinzhis new process of retreading. The new and old rubber fuse POPULAR SCIENCE MONTHLY Electric Pointer [lluminates School Map } ANUAL-TRAINING students at a Cincinnati public school built this map of South America. When the teacher presses a switch, all of the sections of the country producing rubber, say, are lighted up simultaneously. There are switches for ni- trates, fruits, silver, and other products of the southern continent. The map is used in study- ing economic geography in this case, but of course other classifications and arrange- ments of switches could be arranged. EVERY person in the United States has the equivalent of 48 slaves. There are 700,- 000,000 mechanical horse- power developed in this country and the average work capacity ef one human being is one-eighth horsepower. school. September, 1995 5s ORR OR ie wt ae See Ne > Electrically operated map in classroom of a Cincinnati Pressure of electric switch ac bottom of map illumi- nates section of the country that is the subject of class study, Hat Held On by Vacuum Button when Wind Is Blowing CLEVER manufacturer has devised a means whereby he claims a straw or felt hat sticks to the head, tight as a mustard plaster, in a stiff gale. The de- vice consists of a small molded button fastened to the hat through a buttonhole in the front of the sweatband. When the hat is placed on the head, the button sticks to the forehead on the vacuum principle. The grip is out of sight when worn, and is said to be comfortable. . German Zoo Uses Rum as an Anesthetic for Animals ILDanimals incaptivity occasionally require surgical operations, and until recently the accepted practice of the veterinarians who performed them was to use chloroform for an anesthetic. Animal surgeons in the famous Hagenbeck Zoo, near Hamburg, Germany, however, have discovered that animals submit to surgery better when drunk than when subjected to the usual anesthetics. Accordingly, when now a lion, or a tiger, or a hippopotamus needs a little dental work or other surgical attention, it is fed huge quantities of rum or cognac. Then, when it sinks into a drunken stupor, it is chained, and the surgeon performs his work with no pain to the patient or danger to himself. Scientists on the Trail of 2 New Element HE announcement was made a few weeks ago that three German chemists, Drs. Walter Noddack, Ida Tacke,and Otto Berg, have discovered two of the remaining unknown elements of the periodic system, Nos. 43 and 15, and have named them ‘‘masurium” and “rhenium.”’ Both elements are exceed- ingly rare and constitute one-billionth part of the earth’s crust. Hafnium, No. 72 in the total list of 92 elements, was dis- covered about a year ago. Numbers 61, 85, and 87 still are unknown. The element No. 61 is believed to belong to the rare earth metals. Doctor Lapp, a noted American chemist, has succeeded in observing faint lines of the spectrum of element No. 61, and it is highly probable that the element will be isolated in the near future. A New Distress Signal Fits in Palm of the Hand ERE is a brand new distress signal called the‘‘stress- nal.” With it you may scare away a bandit or burglar, but it ean’t hurt him. It makes a lot of noise by firing blank cartridges—10 of them—in rapid succession, and its inventor claims that the noise is heard easily half a mile away. This big surprise for the hcld-up man fits in a woman’s purse and may be carried in the palm of the hand ready for action as pictured. Pressing the button with the finger starts its rapid-fire action. If you let it drop from the hand it keeps on firing and the would-be bandit flees in terror. Removing two small screws opens it for reloading with 10 more blanks, and then it is ready for another attack. Simple distress signal Sept C Pp b Tr i nme dawwerkd ee ae

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nber, 1925 innati llumi- study, of 2 e a few German ck, Ida ered two nents of and 75, 1m” and exceed- billionth um, No. was dis- bers 61, eved to Doctor ist, has s of the id it is will be its in E isa id new signal ““stress- Vith it " seare indit or but it t him. 2s a lot y firing 1 rapid 1s that > away. ip man carried ‘tion as ith the you let . firing terror. pens it s, and September, 1925 POPULAR SCIENCE MONTHLY Folding Baby-Carriage Fits in Suitcase The folding carriage as a dolly buggy. The upper picture shows the small size into which the carriage collapses BAB Y-CARRIAGE that, when folded, can be carried like a hand- bag or in a suitcase is the latest development of the collapsible carriage. The “Dinkie,’ invented in England, weighs only 14 pounds. The body is of pliable waterproof ma- terial, supported by a rigid framework. It can be used, also, as a go-cart, a cot, a high chair, or baby’s’ bath. Thus a father can carry in one hand furniture enough for baby’s needs during the week-end outing. A NEW method of mos- quito prevention consists in mixing oil with sawdust which, when “sowed” on the water, sinks, and re- leases oil for four or five days. Engineers Move a 280-Foot Bridge in London N THE rebuilding of the famous Waterloo Bridge in London, a remark- able engineering feat was accomplished recently, when a 280-foot span of the temporary steel bridge was moved bodily for a distance of 93 feet. The span was moved along steel girders by eight men turning winches that slid the giant framework and its 500 tons of weight at the rate of four feet an hour. The historic Waterloo Bridge, which has been weakened by the sinking of its central piers may be destroyed. Disk Points Warn of Poison Bottle in the Dark PRICK means “look out.” Fum- bling in the dark through the medi- cine chest, where poison should not be kept, but often is, a person cannot make a fatal mis- — take if the poison | bottle is equipped with the new type of safety bottle- stopper illustrated. The warning comes from a metal disk with sharp projecting points, which is held to the bottle by pushing the cork through it. Danger in Spoiling Your Dog REAT your dog as a dog and not asa human being, warns Dr. Minas Joan- nides of Minnesota. Dogs may carry tuberculosis, diphtheria, scarlet fever, measles, smallpox, and rabies. They are subject to tapeworm and often carry fleas, ticks, and lice. If you make a dog a member of your family, be sure to keep him clean and train him to avoid contact with infected materials, says Doctor Joannides. Don’t let him eat off your plate. Homemade Haircut Improved by Neck-Shaving Guard YOU could manage to shave the back of your neck, the home barbering stunt would almost pass as professional. Get- ting their wives to do it is the solution for some men but, in strict confidence, this doesn’t always work out satisfactorily. W. C. Bridges of Muscatine, Ia., has invented a neck-shaving guard to solve the problem. It consists of wire adjust- able to any desired shape of neck trim. The wire is covered with a rubber tube, and is held in place by an elastic band that fits around the head. Offers Huge Cash Prize for Morphine Substitute NE hundred thousand dollars is the dazzling prize offered chemists to induce them to discover how to manu- facture a cheap substitute for morphine. The discovery must be made within the next five years. Herman A. Metz, of New York City, is making the offer in the hope of doing away with the drug evil. Morphine is now derived from opium. If it could be made synthetically, much cheaper than that derivedfromthe poppy, Mr. Metz believes that the supply of opium would be killed at its source. It would no longer pay to grow the poppy. The magic formula, if discovered, must be guarded very carefully to keep the drug from being manufactured and spread among addicts. 51 Six-Surface Razor Strop Lasts a Lifetime ‘THE difficulty of keeping the surface of a razor strop in good condition has been solved by an English inventor, who has designed a razor strop with six sur- faces actually forming three strops in one. When one section has worn out, it is cut off at the ends, and the next section used for stropping. The base of the strops is made of a fiber composition specially treated with a dressing that is said to give the razor a good edge without injuring the blade. The inventor claims that this many-sided strop will give a lifetime of service to the user. Jumping-Jack Shoes Provide Thrills for Children ] BAPING through the air like a kan- garoo is the exciting sensation offered to children by the recent invention of shoes with springs. These novel exercis- ing toys are strapped to the feet in the same manner as roller skates, and the wearer can walk, run, jump, or dance on them. The steel springs, while of unusual strength, are extremely elastic. The effect produced is said to be like walking on air. Each shoe has two spiral springs. The lower end of each spring is fastened to a sole that prevents the springs from in- juring carpets or marring floors. With a little practice, it is said, a child can make enormous leaps. Boys using the new spring shoes to play ‘‘leap-frog.’’ Notice the soles attached to the bottoms of the springs to give sure footing and prevent floor marks

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FRR IVS IE I FRY Ind 3! Be: 4 * ae Ai a 2 re 52 POPULAR SCIENCE MONTHLY & Novelties of the Road ~*~ - Sand Yacht Runs on Wheels Clipping along through the salty spray, Miss Joan Mitchell, an English golf star, drives her rubber- tired “‘sand yacht’”’ over the wet, smooth beach at Ayling. Her pet dog rides in the small back seat A Mechanical Roadway This ‘‘me- chanical highway,” consisting of four rollers under the rear wheels, facilitates adjustments under load September, 1925 ‘*Turf-Board’’ Riding Newest Motor Sport At a recent cycling exhibition at the Crystal Palace, London, par- ticipants displayed their skill on surf-boards attached to motorcycles, While “‘turf-board”’ riding is said to be not quite as difficult as “‘surf- board” riding, it is considerably more uncomfortable and bumpy Builds Midget Roadster One of the most perfect working models of an automobile ever built is this miniature four-cylinder sport model roadster made by Ralph §. Webber of Hoopeston, Il. Traffic Signal also Supplies Time Warning By a mechanism that slowly draws a veil over the “stop” and ‘‘go” signs, this new traffic signal tells drivers how much time is left to cross the street before the stream of traffic will start in the opposite direction Sept oh af ~y wht 28 oe, CO es

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ber, 1995 N, par- rcycles, : “surf- bumpy ister working er built er sport alph §. n, Ii. ‘g0” TOSS September, 1925 POPULAR SCIENCE MONTHLY 53 Where Fire-Fighters Go to School Thrilling Feats Test Their Nerve Having mastered the use of scaling lad- ders, pupils in the Fresno firemen’s school learn to support themselves on the ladders with both arms free, using safety belts fas- tened to the ladder as pictured above HE fire department of Fresno, Calif., full-fledged member of the department, he claims the distinction of having the must pass through weeks of intensive only school for the training of fire- training in breath-taking feats of rescue. men outside the City of New York. Before He must learn to scale the walls of sky- any applicant can go on the payroll as a__ scrapers with steady nerves; to carry the Fo. - ata \ ee mere naman eemmntennapns Above: How the fireman learns to carry an injured comrade down a life rope from an upper floor of a burning building. Center: Jumping into a life net from a sixth-story window dead weight of human bodies down from pre- carious heights on swinging ropes; and to jump from sixth-story windows into a life net that is spread below. A few of the daily paces that not only test the courage of novices, but train them in the science of fire-fighting, are pictured above. Miss Liberty All Dressed Up MERICA’S God- — - e dess of Liberty ees De Siete hasbeen granted independence. Con- gress decided recently to designate the sta- tue as a national mon- ument and make a special appropriation for its upkeep. Be- fore this, the great torch in New York Harbor, given to the United States by France, was under the custody of the Quar- termaster’s Corps of the U. S. Army. Miss Liberty’s yearly allowance will be about $7000. Ninety per cent of this is needed to pay her lighting bill. Two hundred and fifty-six An airplane view of the Statue fl i of Liberty on Bedloe’s Island. ond lights flash on At right electricians are seen every evening as the working on the huge torch sun sinks below the held in the hand of Liberty for Birthday horizon. These go out at 11 o’clock, but the torch remains il- luminated until sun- rise. To celebrate her fortieth birthday, her custodians decided to give the goddess a bath. Steeple-jacks and other aerial acro- bats were hired and she was scrubbed thoroughly from her gigantic head to her massive feet with brushes and heavy streams of water un- til she shone. Railroad Runs Buses HE New York, New Haven & Hartford Rail- road has gone into the motor business and will operate bus feeder lines to the railroad in Massachusetts, Rhode Island, i Connecticut, and New York.

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New Type Battering-Ram Aids Firemen in Fighting Blaze | Spomaatrmgistad the hardest part of the fireman’s job is to get at the fire so as to be able to play the hose on it. This novel two-man battering-ram has been developed by the New York Fire Depart- ment for use when it becomes necessary to batter through a wall or ceiling in order to get at the fire. Ordinarily, an ax can be used for this purpose if the structure is of wood, but the heavy battering-ram will be far more effective than an ax for use on concrete and steel construction. Practical tests by the Fire Department already have demonstrated the remarkable efficiency of this device. New Synthetic Motor Fuel NE more fuel possibility is a new syn- thetic alcohol known as ‘‘methanol,”’ imported from Germany. It is a wood alcohol produced from coal and water, and is a result of researches carried on in Germany during the war, to find a sub- stitute motor fuel. Pipe-Wrench Has a Reversible Jaw T IS claimed that the pipe-wrench shown at the right will turn a pipe in either direction with ease, no matter how tightly it isset. The jaw can be taken out and re- versed so that it is an easy matter to get at any pipe, even when it is placed very close to a wall, ceiling, or floor or when it is jammed up against other pipes. COAL - MINE explosions are most likely to occur between six and nine A.M., and between three and seven P.M. An adjustable jaw wrench especially useful POPULAR SCIENCE MONTHLY T-Square Held by a ee ‘THE short cross piece of this remarkable T-square incloses a pow- erful permanent magnet. A piece of steel is set into the edge of the drawing-board and ground absolutely flat and square. The magnet is so powerful that it is claimed it will hold the T-square tightly in posi- tion even when the draw- ing-board is held up edgewise as shown in the illustration at the right. Because of the smooth- ness of the steel surfaces, it is said that the T-square can be moved along the drawing-board just as easily as without the magnet. September, 1935 T-square is held to drawing-board by magnetized cross Pieces BONES discovered in volcanic ash in Mon- tana, show that tapirs and rhinocerogeg once inhabited that region. Setting brads is made easier by this tool’s magne- tized tip RECENTLY Dr. A. H. Lambert, of the Eastman Kodak Company’s_ research laboratories, announced the discovery of a mysterious ingredient in gelatine that may make it possible to snapshot a bullet in flight or a flash of lightning. The discovery was made by Dr. S. E. Sheppard as the result of experiments ex- tending over several years. The mys- terious ingredient has proved itself valuable also in the transmission of pictures by radio. Brad Setter Eliminates Hammer when Fastening Packing-Box (CONCEALED inside this remarkable little tool is a powerful magnet, Pulling the outside sleeve toward the handle with the first two fingers exposes the end of the magnet and when the magnet is touched to the head of a brad and the sleeve released, the magnet draws the brad into the tube. The next operation is to force the brad into the wood by pressure on the handle. The brad is held straight so that it cannot bend and the plunger pushes the head slightly below the surface cf the wood so that sealing-wax can be applied if, for instance, the box contains an article of considerable value. ‘Electric Hand’’ Lays Bricks LMOST human in its motions is an electric gripper that stacks bricks on a truck ready for the kiln. This machine has rows of grippers, which in reality are electric fingers. The grippers are at- tached to the bottom of a segregator suspended from a crane. As the freshly made bricks travel from the _ brick- making machine, the rows of grippers pick up a brick in every “hand,” and deposit them. spaced evenly, on the truck. Novel Flexible Tipped Soldering Iron hl RADIO work espe- cult to reach the parts that are to be soldered, because the body of the iron strikes some other part in the set. The novel electric soldering! iron shown at the left is said to overcome all difficulties along this line because the tip is ar- so that it can be turned in any direction. It is rated at 100 watts and consequently is suitable for all kinds of work ex- makes Because of its flexible tip, this 100-watt solder- ing iron is invaluable for mending delicate and intricate parts, such as are found in a radio set cept in cases where a heavy duty iron is neces- sary. cially, it often is diffi-; ranged in a swivel joint ‘ Or ot

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ber, 1925 S pieces in Mon. OCeroses 1m mer -Box 1arkable Magnet, ard the exposes hen the f a brad magnet che brad handle, C cannot he head wood so | if, for ticle of ricks 18 is an ricks on machine lity are are at- rregator freshly brick- zrippers 1,”’ and on the ‘on k espe- is diffi-; e parts yldered, of the > other, The dering’ > left is, me all his line is ar- 2] joint turned It is ts and uitable ork ex- here @ s neces- September, 1925 OST ingenious parking tower for Mee was invented recently by J. E. Morton of Purdue University, Ind. It consists of an all-steel tower in which a central drive shaft is connected through a train of ge sufficient power to operate an endless-chain elevator of multiple parking car- riages, each automobile having its own individual parking carriage. The tower covers a ground space of only 16 by 22 feet, though it is of vari- able height, depending on the number of cars to be parked. ; A ecar-owner drives up to park his machine. The gperator brings an empty parking carriage to the floor level, the owner drives his car into the car- ~iage, locks it, steps out, and is given a check cor- responding to the number of his parking carriage. Guide rails on the floor of each carriage prevent the automobile from slip- ping; and each auto is protected also from drip- pings from the auto above it. Merely by reversing the motor, the op- erator can bring a car- riage to any Te floor level by runs like a ferris wheel Hungers for New Inventions I ALWAYS have had a leaning toward new inventions, and your magazine sup- plies exactly what I hunger for.—W. W., Reidsville, W. Va. Tractor Uses Rubber-Tired ; Wheels for City Trips preom Germany comes the good- looking automobile shown below. It is intended primarily for use es a tractor on a farm, but with the addition of the rubker-tired wheels it can be used as an ordinary car and taken into the city, without fear of injury to the roads. Farm tractor is equipped with rub- ber-tired wheels for city streets ars with an electric motor of POPULAR SCIENCE MONTHLY Parking ‘Tower for Autos Saves Ground Rent the shortest possible route. The carriage at the top passes over and comes down on the opposite side, while at the bottom it goes under the floor and comes up on the other side of the tower; it can be stopped at any floor level and is at all times under the instant control of the operator. The parking tower comes in several units— 16, 20, 30, 40, and even 50 carriages. One operator ean handle a battery of from five to 10 parking towers installed in a large central parking station, as each tower may be con- nected with an indicator in the central control room. The indicator tells the op- erator the exact location of every carriage, whether filled or empty, and the direction of its travel. Should he attempt to bring a particular carriage to the floor level, and it pass the floor, it would simply keep on going until he reversed the motor and _ brought it back to the right position. Nor could the owner enter it until it was safely stopped for him, when he could go in, unlock his machine, and back out into the street without delay. 55 Auto-Bus Has a Sliding Top SIGHTSEEING trip through the Big Tree district of California is spoiled if tourists cannot see the majestic height of the great trees. In order that no detail of the scenery be lost, a fleet of sightseeing cars operating in this part of the Yosemite is equipped with tops that can be rolled back. In case of a sudden shower the central section may be replaced quickly. Pee ene ME RS Engine f Columbia, Canada. nary flanged traction wheels. provided the necessary pulling power. The locomotive runs on a specially constructed wooden track and loads of lumber are hauled in a trailer. or Hauling Lumber Is Made of J \ , JHAT is probably the strangest homemade locomotive in the world is in use at a logging-camp in the woods of British un E. J. Byfield put together a few junked motor parts and produced an engine, which is mounted on a set of ordi- A few yards of linked belting IT RECENTLY has been discovered by investigators into the sub- ject that a plague of mosquitoes in certain localities is due to poor engineering practice in the construction of highways, railways, and reservoirs. Uneven surfaces, crevices in a loose joint and in walls provide hatching holes for the pests.

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POPULAR SCIENCE MONTHLY September, 1935 Latest Novelties in Aviation Balloon Targets .- They look like toy balloons, a = but the big bubbles at the ‘ left really are targets used by army aviators at Crissy Field, San Francisco. As the balloons float in the air the fliers pepper them with bullets from machine-guns

New Sun Compass Because of inaccuracies in magnetic compasses in the polar regions, each of the airplanes of the Mac- Millan Expedition | this summer is equipped with this new instrument that gives directions accurately with the aid of the sun

Ford Mast Here is the great airship mooring-. mast just completed at the Ford airport at Dearborn, Mich., as a harbor for the Los Angeles and other big dirigibles. It is 201 feet high, 26 feet higher than the navy mast at Lakehurst, N. J. A five-passenger ele- vator runsto thetop

New Thriller Racing 60 miles an hour on a motor- cycle at St. Paul, Minn., Al Black- stone, dare- devil acrobat, catches rope ladder dropped from plane, and climbs safely aboard

pa ERX 7\ hGH ae be i: ie

England Has Air Glider Races Model gliders in recent cup races.of the British Society of Model Aeronautical Engineers at Sudbury, England. An article in the July POPULAR SCIENCE MONTHLY described in detail how to build successful gliders of this type

Septe:

The | can b by < easily show? use as canoe camp’ desi of t rubl fran cart It is in 1 esti two mas for" fast of 1 pol the cak ro) tl rf Q. ofr a a

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Mber, 1925 ipass acies in ses in each of e Mac- nN this -d with nt that urately he sun September, 1925 The light boat can be carried by one man easily. It is shown here in use as a sailing canoe and as a campers’ tent REMARKABLE collapsible sailboat that can be carried in a bag has been designed recently to answer the demands of the sportsman. Made of vulcanized rubber and canvas stretched on a wooden framework, it is very light. A man can carry it easily even when it is fully set up. It is built in sections and can be assembled in 10 minutes, the inventor claims. The sails are perhaps the most inter- esting part of the equipment. There are two, one twice as large as the other. The mast for the larger one is stepped at the forward end of the cockpit, and the other fastened through the deck at the back of the cockpit. When the sails are fastened to a ridge pole set up in the middle of the cockpit, they may be converted into a tent or boat cabin. Or if the camper prefers, he can POPULAR SCIENCE MONTHLY 57 JOdd, Sailing Canoe ' Serves as Tent | New Collapsible Boat for the Sportsman set up the tent outside of the boat beside the stream, and use the boat as an ordi- nary canoe. Comfortable seats with backs are pro- vided. The combination canoe and sail- boat will carry four persons, although, as in the case of any canoe, greater speed can be obtained when paddling if a lighter load is carried. Ideal for the Embryo Mechanic The word ‘‘ Popular” is very significant, for at my home it is a contest between my three sons and myself to see who gets the first look. It is an ideal magazine for the embryo mechanic, to say nothing of the articles of a scientific nature that are most interesting to those who like to know.—Dr. B. C. W., Normal, Neb. Stilts Are Carpenter’s Stepladder (MISSING up and down a stepladder was not to the taste of the Paris carpenter shown at the right. He worked fast and was always having to move his ladder. As a boy his favorite sport was walking on stilts. He still had a pair. He got them out and found them a splendid lad- der substitute. The foot supports are adjustable to various heights. Golf Club Prevents Slicing AN AMATEUR golfer of Boston, John * T. Manning, has invented a new club, adriver, which he claims cannot slice the ball. Vertical grooves fluted to cor- respond with the curvature of a golf ball are molded on the club’s face. When the ball is struck, the ridges catch and drop it into one of the grooves, preventing motion sideways. Pick Stool Folds into Handbag Carpenter using stilts as a substitute for stepladder HEN folded, this collapsible stool becomes a lady’s handbag, as shown in the inset. It has a pocket on the outside for handkerchief and purse, and is fitted with a small mirror. After the stool is unfolded and before it is set up, the cushion on the seat is filled with air. It is designed for use at picnics, in automobiles, on camping expeditions, or in crowded railway stations.

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POPULAR SCIENCE MONTHLY a . : ee “s i fe New Drawing Device Trains Student’s Eye O TRAIN the eye of the art student in form, proportion, perspective, value, and color, Anson K. Cross, of the school of the Museum’ of Fine Arts, Boston, has invented a device the use of which introduces a new and easy method of studying art. The device consists of a sheet of clear glass protected in a frame that holds a spirit level, and a white card that slides behind the glass. Two lenses slide be- tween the lower members of the frame. These are used in painting. The student draws on the glass with a special crayon. When the sketch is finished, he removes the opaque white card and views his drawing superimposed upon the model. The faults of the draw- Occupant Serves as the Pole of Portable Bathing-Tent TREELESS bathing-beach offers no inconvenience to the bather who carries a portable bathing-tent of cretonne, a recent invention from London. It has the shape of a bag with a top section that fits on the bather’s head like a hat. It envelops the whole body to permit a change of clothes, the bather himself sup- porting the tent. ing are made clear. By constant use of the lenses to test sketches drawn from memory or observation, the student trains his eye to observe accurately and report form and color. Collapsible bathing-tent is made of rubberized cretonne September, 1925 Discovers Moonlight Speeds Growth of Bacteria (,2OWTH and activity of bacteria can be speeded up by the sort of light supplied by the moon, T. F. Morrison graduate student at Princeton University. has discovered through experimentg on the kind of micro-organisms that cause dead fish to shine in the dark. This work appears to confirm results obtained pre. viously by E. G. Bryant, in South Africa who found that fish exposed to moon. light spoiled more quickly than those kept in the dark. Bottomless Sailboat Is Built for Use of Bathers N°? USE to bail water from the bottom of this sailboat! It cannot be done. It is intended for the use and pleasure of bathers. A sail and three floats resembling huge basketballs make up the principal parts of the pleasure craft. Strips of canvas stretched between two horizontal poles serve as seat and support for the feet. A » double-bladed paddle is provided. A sail, three floats, and a canvas seat make an interesting toy for the seashore frequenter Wheelbarrow, train, or kiddy- kar can be made from this chair, the invention of two pro- _ fessors. A child’s imagination * must travel far to exhaust the chair’s possibilities as a toy i Child’s Chair Is Adaptable to Many Games HEN children use ordinary chairs, which usually are favorite play- things, for trains, ladders, or beds, their fun often ends in grief. Household furni- ture is scratched and broken too easily. Two university professors, F. W. Hart, of Berkeley, Calif., and Prof. Patty Smith Hill, of New York City, put their ideas together and invented a play chair that children cannot break, or, rather, one that can be broken easily without harming it. Children can take the chairs apart and make them into other playthings— carts, wheelbarrows, wagons, or trains. THE number of motor-cars manufactured in the United States in a month is more than four times as great as the number of bathtubs shipped from factories during the same period, according to statistics from bathtub and motor manufacturers. Septemb One mak talk that the abo inst N pump This 1 he fou Near | dynan One si begin tivitie At Ol fu Titus a the nace latior posit: radia been meng subje teres El thin] vers! the f ing | heat sult chin clea: thor A engi ona sha fron sha carl and tak ang

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T, 1925 ottom done. sure of y huge Parts “aNnvas Poles ured nore er of ring stics 1925 Septe mber, One of the miner-cabinet- maker’s masterpieces —a talking-machine cabinet that he built and whittled in the attractive design shown above. J.B. Shedd is a self- instructed cabinetmaker POPULAR SCIENCE MONTHLY He Does Two Things at a Yime and Does Them Well there are EAR Bessemer, Ala., cozl-mines. On the night shift is 2 man who tends an electric pump in the very depths of the earth. This man i; J. B. Shedd, and at one time he found te nights long and wearisome. Near by his pump was a number of empty dynamite boxes; in his hand a jack-knife. One suggesed the other, and that was the beginning cf J. B. Shedd’s whittling ac- tivities. At first he whittled only crude shapes , from the boxes, but gradually, achieving a greater ease, his pieces of carving as- sumed a more finished shape. Then, instead of using merely one piece of wood, he made a box and decorated the sides and top of it. : One thing led to another and before Shedd realized it, he found himself to be a quite passable cabinetmaker with a knack at decorative whittling, and a reputation for making attractive bits of furniture. On the table at the left are shown some other pieces from Mr. Shedd’s jack-knife, the table itself being one of his prized achievements. pieces and demonstrating how he works with his jack-knife Above he is holding one of his smaller No longer did Mr. Shedd find the nights too long in the coal-mine; some- times they weren’t long enough! Among the articles of furniture he has carved are tables, chairs, bookcases, and a talking- machine case. Mr. Shedd says he never has had a les- son in cabinetwork or whittling. He still remains at his job tending the electric pump, and he has discredited the old proverb that it is possible to do only one thing at a time and do it well. A Vacuum Chimney-Sweep Cleans Furnace Flues OURTESN years in the furnac) business gave Titus Russc!l, of Albion, Mich., a thorough knowledge of fur- nace opera_ion. The accumu- lation of Gust and carbon de- posits, or coot, in the furnace radiating channels has always been one of the greatest fire menaces, ond it was in this subject that Mr. Russell in- terested himself. Eleven years ago he began thinking of a method of re- versing the air draft through the furnace pipes, and a clean- ing system based upon expert heating principles. .The re- sult has been a ma- chine that is said to clean furnace pipes thoroughly. A 22-horsepower engine is mounted on a truck. An iron shaft extending from the crank- shaft of the motor carries flywheel andfan. The in- take is at right angles to the hub and draws through a series of tube sections that can be placed through any cellar win- dow to the furnace. The out- let is at the rear base of the outer case, releasing into a huge sack. A mouthpiece, attachable to any needed length of tube, is so constructed that it will fit any furnace door with an airtight grip. With this ap- paratus the work of a chim- ney-sweep is done at one sweep, and the entire furnace cleared of soot. Above: Flue-cleaner truck drawn up beside a residence, showing the great dust bag, flywheel, and tube. Below: Man holding the mouthpiece of the flue-cleaner that is adjustable to give an airtight fit to the door of any furnace. A 22-horse- power motor on the truck runs the flue-cleaner Other uses have been made of this furnace -flue cleaner. For in- stance, the end of the tube was put in a load of gravel, the motor started, and the gravel moved in a steady stream through the machine to a neat pile 40 feet away, all in less time than two men could remove the load.

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POPULAR SCIENCE MONTHLY New Drawing Device Trains Student’s Eye T°? TRAIN the eye of the art student in form, proportion, perspective, value, and color, Anson K. Cross, of the school of the Museum. of Fine Arts, Boston, has invented a device the use of which introduces a new and easy method of studying art. The device consists of a sheet of clear glass protected in a frame that holds a spirit level, and a white card that slides behind the glass. Two lenses slide be- tween the lower members of the frame. These are used in painting. The student draws on the glass with a special crayon. When the sketch is finished, he removes the opaque white card and views his drawing superimposed upon the model. The faults of the draw- Occupant Serves as the Pole of Portable Bathing-Tent A TREELESS bathing-beach offers no inconvenience to the bather who carries a portable bathing-tent of cretonne, a recent invention from London. It has the shape of a bag with a top section that fits on the bather’s head like a hat. It envelops the whole body to permit a change of clothes, the bather himself sup- porting the tent. ing are made clear. By constant use of the lenses to test sketches drawn from memory or observation, the student trains his eye to observe accurately and report form and color. Collapsible bathing-tent is made of rubberized cretonne September, 1995 Discovers Moonlight Speeds Growth of Bacteria (,2OWTH and activity of bacte be speeded up by the sort supplied by the moon, T. F. Morrison graduate student at Princeton University has discovered through experiments on the kind of micro-organisms that Cause dead fish to shine in the dark. This work appears to confirm results obtained pre. viously by E. G. Bryant, in South Afrieg who found that fish exposed to moon. light spoiled more quickly than those kept in the dark. ria Can of light Bottomless Sailboat Is Built for Use of Bathers N° USE to bail water from the bottom of this sailboat! It cannot be done. It is intended for the use and pleasure of bathers. A sail and three floats resembling huge basketballs make up the principal parts of the pleasure craft. Strips of canvas stretched between two horizontal poles serve as seat and support for the feet. A » double-bladed paddle is provided. A sail, three floats, and a canvas seat make an interesting toy for the seashore frequenter Child’s Chair Is Adaptable to Many Games Wheelbarrow, train, or kiddy- kar can be made from this chair, the invention of two pro- . fessors. A child’s imagination * must travel far to exhaust the chair’s possibilities as a toy HEN children use ordinary chairs, which usually are favorite play- things, for trains, ladders, or beds, their fun often ends in grief. Household furni- ture is scratched and broken too easily. Two university professors, F. W. Hart, of Berkeley, Calif., and Prof. Patty Smith Hill, of New York City, put their ideas together and invented a play chair that children cannot break, or, rather, one that can be broken easily without harming it. Children can take the chairs apart and make them into other playthings— carts, wheelbarrows, wagons, or trains. THE number of motor-cars manufactured in the United States in a month is more than four times as great as the number of bathtubs shipped from factories during the same period, according to statistics from bathtub and motor manufacturers. September One mak talk that the abo inst N pump This 1 he fot Near dynat One s begin tivitir At

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september, 1925 POPULAR SCIENCE MONTHLY He Does Two Things at a Yime and Does Them Well One of the miner-cabinet- maker’s masterpieces —a talking-machine cabinet that he built and whittled in the attractive design shown above. J.B. Shedd is a self- instructed cabinetmaker EAI. Bessemer, Ala., there are N cozl-mines. On the night shift is 2 man who tends an electric pump in the very depths of the earth. This man i; J. B. Shedd, and at one time he found te nights long and wearisome. Near by his pump was a number of empty dynamite boxes; in his hand a jack-knife. One sugges-ed the other, and that was the beginning cf J. B. Shedd’s whittling ac- tivities. At first he whittled only crude shapes from the boxes, but gradually, achieving a greater ease, his pieces of carving as- sumed a more finished shape. Then, instead of using merely one piece of wood, he made a box and decorated the sides and top of it. ? One thing led to another and before Shedd realized it, he found himself to be a quite passable cabinetmaker with a knack at decorative whittling, and a reputation for making attractive bits of furniture. 59 On the table at the left are shown some other pieces from Mr. Shedd’s jack-knife, the table itself being one of his prized achievements. pieces and demonstrating how he works with his jack-knife Above he is holding one of his smaller No longer did Mr. Shedd find the nights too long in the coal-mine; some- times they weren’t long enough! Among the articles of furniture he has carved are tables, chairs, bookcases, and a talking- machine case. Mr. Shedd says he never has had a les- son in cabinetwork or whittling. He still remains at his job tending the electric pump, and he has discredited the old proverb that it is possible to do only one thing at a time and do it well. A Vacuum Chimney-Sweep Cleans Furnace Flues OURTESN years in the furnac) business gave Titus Russcll, of Albion, Mich., a thorough knowledge of fur- nace opera\ion. The accumu- lation of Gust and carbon de- posits, or coot, in the furnace radiating channels has always been one of the greatest fire menaces, ond it was in this subject that Mr. Russell in- terested himself. Eleven years ago he began thinking of a method of re- versing the air draft through the furnace pipes, and a clean- and draws through a series of tube sections that can be placed through any cellar win- dow to the furnace. The out- let is at the rear base of the outer case, releasing into a huge sack. A mouthpiece, attachable to any needed length of tube, is so constructed that it will fit any furnace door with an airtight grip. With this ap- paratus the work of a chim- ney-sweep is done at one sweep, and the entire furnace cleared of soot. ing system based upon expert heating principles. .The re- sult has been a ma- chine that is said to clean furnace pipes thoroughly. A 22-horsepower Other uses have been made of this furnace -flue cleaner. For in- stance, the end of the tube was put in a load of gravel, the motor started, red ore r of ing tics Ts. engine is mounted on a truck. An iron shaft extending from the crank- shaft of the motor carries flywheel andfan. The in- take is at right angles to the hub Above: Flue-cleaner truck drawn up beside a residence, showing the great dust bag, flywheel, and tube. Below: Man holding the mouthpiece of the flue-cleaner that is adjustable to give an airtight fit to the door of any furnace. A 22-horse- power motor on the truck runs the flue-cleaner and the gravel moved in a steady stream through the machine to a neat pile 40 feet away, all in less time than two men could remove the load.

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Dustproof Hood Devised for Furnace Cleaners pa use in cleaning boilers, furnaces, and tanks, a new type of protection against dust, a hood of finely woven canvas that fits snugly over the head and shoulders and is held tightly to the body by elastic bands at the wrists and waist, recently has been invented by Tim Leonard, foreman of boiler cleaners for the United Electric Light and Power Company, New York City. In the mask are extra large lenses that are non-fogging so that the worker can see plainly through dust as he cleans a boiler. The ordinary aluminum sponge respirator, with pneumatic cushion and outlet valve, is fixed inside the head piece. Fireproof material can be used for the hood. The safety device has been declared highly satisfactory by experts and is said to be a great improvement over other protective masks for this purpose. ‘“‘Mystery Lamp” Lights when You Pick It Up A ‘LAMP OF MYSTERY,” so called because it lights when you pick it up and goes out when you put it down, has just been devised as an electrical! improve- ment on the old- time household candle. The secret of its operation lies in an electric dry battery con- cealed in the base, and an in- genious method of making and breaking electri- cal contacts by means of a weight ar- rangement actuated by the lifting or setting Ornamenta]j flashlight lamp and the bat- down of the tery that lights it lamp. POPULAR SCIENCE MONTHLY Handy Utilities for ‘Town, Automatic Safety Device Shuts Off the Gas O PREVENT explosions or asphyxi- ation from escaping gas in gas boilers or furnaces a device has been perfected that shuts off the supply of fuel when the pilot light is extinguished. It con- sists of a small box, C, containing a ther mocouple, which is heated by the pilot light supplied by pipe B. When heated, this metal expands so that it cpens the check valve A, permitting gas to flow from the main pipe to the burner. Should the light go out for any reason, the metal contracts and the ball in the check valve falls again into its seat, clos- ing the supply of gas to the main burner. The gas flow can be resumed only by re- lighting the pilot light. This can be done electrically from a distance simply by pressing a switch button that may be located in the most convenient place. Burner with automatic safety attachment September, 1s Blotter Attachment for Hand Is a New Aid for Writers CNE who has to do much writing wit, pen and ink will find this hang blotter useful. It is held in position by elastic bands that slip over the wig and around the little finger. Begidg blotting, it provides a shield to protec paper from perspiring or soiled handy It also protects the hand when stamping and sealing letters or when using paste or glue. ‘The Hardest Metal Surface A NEW process for electroplating met. als with an alloy composed chiefly of chromium, the hardest substance in exist. ence next to diamonds, recent !y was an- nounced by Dr. Colin G. Fink, professor of electrochemistry at Columbia Univer. sity. The surface produced by this proc. ess is said to be harder than any other known metal surface. Small Movie Machine Designed for Amateurs NEW motion-picture camera that both takes and projects motion pic- tures, made especially for the amateur, recently was perfected in France. The machine takes films cf just half the ordi- nary width, so that regular motion-picture films cut in half lengthwise can be used. A circular cutter especi- ally devised. for cutting film is part of the equipment. The machine takes a film about 790 feet long, which is equivalent to about 2000 feet of standard film. Each “frame” or image measures about one-third by one-half inch. The same machine that is used for taking the views is used in projecting them as shown in the picture below. The The new apparatus used as camera (above) and projector inside reels are replaced by a circular ease holding the projector light; and the machine is placed on a stand that holds two large metal reels. There are two lenses, as shown in the left-hand photo graph, one for taking the pictures and the other for projection. For long scenes, the machine is placed on a tripod to hold it steacy; but for short reels of from 100 to 150 views, the machine can be held in the hand, andin that case an auxiliary motor is used to turn the reels. It is housed in a metal case, and weighs only slightly over four pounds. Its di- mensions are 6.4 by 6 by3 inches. The machine andall auxiliaries are made by a well known manutacturing firm, Paris, France. OLL. to | may not weight, massagl process, The with va under 1 penefic! action tion an ing the $66, HE in the ait to fact on we ment | Ab by de found. is air § tainer Sellin: by we! body M AN conce in th The seam num brass ness fram mak:

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tember, In Hand ters ‘iting wit this Ss Osition by the wrig Besides [0 Protect ed hands Stamping SIN paste tface ting met. chiefly of e in exist. 7 Was an- Professor 2 Univer. this proe- iny other Curs circular and the iat holds are two d photo s and the is placed but for ws, the d, andin used to 1 weighs Its di- 6 by 3 > andall y a well ucturing rance, jector September, 1925 POPULAR SCIENCE MONTHLY Country, and the Home Rolling-Pin Massage for Weight Reduction OLLING oneself out with a rolling-pin os get rid of excessive avoirdupois may not appeal to one who wishes to lose weight, but if the rolling is done with the massaging device illustrated above, the process, it is said, need not be painful. The four sections of the roller, fitted with vacuum cups, revolve over the body under very light pressure, producing the peneficial results from massage. This action is said to stimulate blood circula- tion and to break down fatty tissue, keep- ing the flesh in firm condition. $66,000,000 Paid for Air Holes HE WHO buys ice-cream by the bulk instead of by weight, pays dearly for the air holes in the confection, according to facts revealed at the recent conference on weights and measures at the Depart- ment of Commerce. A billion quarts of ice-cream are made by dealers in this country annually, it was found, but a fifth of the total amount sold is air space that is ‘‘packed”’ into the con- tainers in which the ice-cream is sold. Selling the ice-cream by bulk instead of byweight, it is estimated, means that some- body pays $66,000,000 for the air holes. Wrist Case Invented for Pencils and Pens "THE man who keeps his pen and pen- cils in a newly devised wrist case has them always at hand, the inventor says, and yet out of the way when not in use. The case fastens on the arm with two straps. The pencils are attached to the case with small chains wound on spring reels that hold them in their compartments when not in use. Turning a lever at the top of the case projects a pencil from the holder so that it can be grasped. As it is pulled out, the chain with which it is attached unwinds from the reel. When the pencil is drawn back by the spring reel, it is locked automatically in its compart- ment. Three compartments are provided for the convenience of the wearer. How case is strapped to wrist Father Time Races Stork URING 1924, 2,645,000 babies were born and 1,333,000 persons died in the United States, or one death was com- pensated for by two births. If the num- ber of births and deaths remains the same in 1925, as this rate seems to indicate, 10 babies will be born every two minutes and five persons will die in the same time. Metal Frame Supports New Concession Tent N INNOVATION in the construction of concession tents is embodied in the model pictured here. The framework is made of seamless brass and alumi- num tubing, with joints of brass, which make for light- ness and strength. The frame stretches the canvas, making it water-tight, and Metal frame ready for the canvas The completed tent, with awnings taking the strain off the guy ropes. So simple is the construction, that with but little practice the tent can be put up in 15 minutes. The entire framework is collapsible, and when unfolded is held rigid by cross braces fastened with bolts. Two metal coun- ters, one on each side, are set in the frame. For severe weather four guys are used, and steel pins are driven through holes at each corner of the frame. 61 Aluminum Honeycomb to Double Bees’ Output OOLING bees with a new type of honeycomb made of aluminum is said to add greatly to profits of bee-keepers. By lessening the time needed to manu- facture comb, it is said to enable the bees to double their output of honey. The aluminum combs are painted with beeswax in its pure state and the bees go right ahead and fill them just as if the combs were a homemade article. When filled, the combs are put in a machine called a “honey extractor,’’ which whirls the combs around and extracts the honey by centrifugal force. The combs then can be returned to the hive for the further manufacture of honey. Button Operates Keyless Automatic Lock KEYLESS, automatic button lock recently devised for house doors may be installed in 10 minutes, it is claimed, using only two screws. Merely pressing a button in the center of the knob locks the door, while turning the knob auto- matically unlocks it. A glance at the position of the button shows whether the door is locked or unlocked. Knobs may be had in either glass or metal. This type of lock is especially use- fulfor the bathroom where the door must be locked frequently. A key is used only on the outside of an outside door, and here the keyhole is placed in the cen- ter of the knob, where it is easily found in the dark. The button lock is a compression- spring, unit-type lock, which auto- matieally adjusts itself to the thick- ness of door as it is being installed. The inner knob is detachable; but not the outer knob. r Pressing a button locks the door

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Hat-Hanger Fits on Clothes- Rack POPULAR SCIENCE MONTHLY has pictured in an earlier issue a collapsible clothes-hanger, such as shown above, but with- out the hat-holder, which the inventor has added for use in small closets, where often no provision is made for hats. When extended, the hanger has four substantial hooks for clothes. When it is not in use, it occupies very little space Improved Meat-Grinder With a mere shift of a lever on this improved meat-grinder, the degree of grinding from fine to coarse, or contrariwise, is changede This little attachment makes it un- necessary to remove one cutting disk and insert another, as it has heretofore been necessary to do POPULAR SCIENCE MONTHLY Bristle Filler for Brooms You need waste very little of your broom bristles now that a new filler can be fitted into the handle of a broom when the old one wears out. A spring gives the broom flexibility so that the fiber bristles can be worn down to an inch before discarding New Ideas for the Combination Range and Cabing September, 1925 Range and Cabinet in One Thoroughly insulated, the mak- ers claim, so that no hot air can spoil the edibles, this combined kitchen range and cabinet is a boon to housewives, saving many steps. The cabinet forms a support for the range, and has spaces for pots and pans and kitchen cutlery, as well as drawers for spices, flour, and sugar To Remove Cap Jar; Now that canning days ar here, good housewives ar looking for the most eff. cient utensils. Above js shown a new jar-top re. mover, said by the inventor to be ‘‘different.”” A self. adjusting link grips and g. curely holds any size jar cap. It is very easy to handle and works quickly Food Grater. Has a Glass Top Said by its makers to be able to grate any kind of food, the little grater below is distinguished ~, {rom other graters by , its glass top, which is used for the pur. pose of pushing down the food and thus saves fingers from being caught Dishwashing Made Easy Dirty dishes are placed in the sink rack. The hose is turned on, the soap lever pressed, dishes are sprayed with hot soapy water, then with clear water. Dishes remain in the wire rack until thoroughly dry, or remain until the next meal is set Septembe P This sc alumin sils, as scrapel The s vantag ting tl on ed grating Vegi Vege cut 3 desif chin devi man veg pist leve shay cha: scre cut giv tou

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Ap Jars days are AVES are nost eff. \bove jis r-top. te. inventor A self. S and ge. size jar easy to quickly rt Has Top ETS to be y kind of > grater nguished ters by P, which the pur. »ushing ‘ood and fingers S Caught Easy the sink on, the ies are er, then main in ily dry, al is set september, 1925 POPULAR SCIENCE MONTHLY Up-to-Date Kitchen Saves the Housewife Many Steps Safety Window-Cleaner As shown in the picture at the right, a square cleaning pad is placed at the end of abentrod. The operator stands on the inside of the window and passes the cleaner back and forth until the window is spotless Wooden Pot-Scraper This scraper is for use on aluminum and glass uten- sils, as any kind of metal scraper is bad for ther. The scraper has the ad- vantage, too, of not set- ting the housewife’s teeth on edge by contact of grating metal on metal Seven-Design Vegetable Cutter Vegetables may be cut in seven different designs by the ma- chine shown below, devised by a French- man. The slices of vegetable fits under a piston operated by a lever. Variation in shape is obtained by changing the cutting screen. Vegetables cut in this manner give a _ professional touch to a dinner Icebox like Filing Cabinet Instead of shelves this refrigera- tor has closed compartments that slide in and out. This con- struction serves several purposes, the most important of which is that as the needed drawer is pulled out, it automatically closes the box, thus maintaining an even temperature at all times, besides being an advance over having. to stoop to see what supplies every shelf contains Oyster-Opening Set At right is an oyster-opening set from France. The oyster shell is Placed in a cavity in the block of wood and pried open by a clawed knife, used also for detaching the oyster from its shell. The oyster then is placed in the wire rack 63 Milk-Bottle Separator There is now on the market a new kind of milk-bottle that keeps the cream separate from the milk, al- though, if required, the cream and the milk can be mixed by the simple means of turning the bottle upside down. It is claimed that by using the separator and pouring off the cream, a whipping cream is obtained or cream suitable for the morning coffee or for your favorite cereal Water Will Not Boil Over Water will boil up and over very “quickly when cooking greens. It is claimed by the inventor that by the use of the ring shown above, the greens are held down, giving more room for the water to flow and bubble, and thus preventing boiling over and saving constant watching

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64 POPULAR SCIENCE MONTHLY Simple Cam i p Stove Is Heated by Blowtorch oF ie. # NY make of blow- torch may be used to provide heat for this compact collapsible camp stove. Most per- sons have such a torch about the house or can borrow one for the week-end. The stove is simple in construc- tion and weighs only 614 pounds. It has two burners and is 10 inches high. The sup- ports, which fold up around each end of the stove when not in use, set firmly on the ground and hold the stove se- curely while the camp- er’s coffee and bacon for breakfast are cook- 8 ed Heated by a blowtorch, this simple little stove has room for frying and cooking, folding up when not in use ing just outside the flap of the tent, 1000-Watt Lamps Grow Grass on Barren Lawn ie POWERFUL electric lights strung over a barren lawn can force grass into rapid growth, why should not similar treatment make hair grow on a bald head? Tests with 1000-watt lamps at the Cam- bridge, Mass., Electric Light Company have shown astonishing results on grass growth. Dr. Andreas F. Christian, of Boston, claims that bald heads may be covered, beards coaxed on clean-shaven faces, and bobbed hair grown long in a short time, by use of strong artificial light. The only requisite in cases of both lawns and heads, he says, is that the germ of life must exist. Ears Grow Tired, Too 2 iter ear apparently becomes physi- cally tired, asserts Prof. Albert Sid- ney Langfeld, director of the laboratory of experimental psychology at Princeton University. By means of radio apparatus, Professor Langfeld led the sound from oscillating vacuum tubes to head phones that were adjusted until the wearer declared the sounds reached each ear with absolutely equal volume. Then one phone was re- moved, and the hearer required to listen with one ear fora minute. At the end of that time both phones were used again, and invariably the subject reported hear- ing the sounds more loudly in the ear to which the phone had just been added. Ceiling Insert of Steel for Concrete Buildings ELOW is shown a recently designed steel insert that is fitted in the molds of concrete ceilings, so that when the concrete is flowed into the molds, the insert becomes firmly embedded as the mixture dries. Thus there is es- tablished asocket that will sustain pipes or other fix- Lures. A threaded unit is inserted sideways through the nar- row passage into the hollow 3quare, where it is straightened out and the fix- ture. screwed in- to it. How steel insert sets in a ceiling September, 1995 Photographic Plates May Be Developed in Daylight F ghasn research extending over 3 period of several years, Dr. H. man, a chemist of Philadelphia, discovered that the process of developing and fixing g photograph negative in the daylight when it can be more carefully watched and controlled, is a decided advantage over the prevailing method of darkroom development. If the exposed plate is first placed in the hyposulphite of sodium solution, it will dissolve and remove only the particles of silver bromide that have not been acted on by light. When the fixed plate ig re. moved from the hypo solution, it is per- fectly transparent, without a trace of indication that it has been exposed in the camera. Yet it bears in latent form the picture photographed. The fixed plate or film may be exposed to daylight without injurious effect on the latent picture, which can be developed in broad daylight by submerging the photographic plate or film in a solution of chloride or bromide of mercury. Oxygen-Generating Mask for Miners and Divers ASas mask that produces its own oxy- gen has been invented recently by H.C. Carter of Victoria, Australia. Reneyw- ing gas in masks has been for a long time a leading problem in making oxygen masks that are used by miners and divers, Collapsible Hand-Cart Takes Little Space for Storage ON of the greatest problems offered to the owners of hand-carts is the amount of space they take up when stored away for the night. This new German invention seeks to overcome this difficulty. The bottom of the cart divides at the center line and the halves fold up against the sides. Then the user pulls a lever, which bends the axle and the bottom frame members, which are hinged at the center, and the entire hand-cart can be pushed into a space less than two feet wide. The picture illus- trates the hand-cart in the process of being folded. q % This hand-cart folds into space less than two feet wide when work is done

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nber, 1995 'y Be it Over 4 be Leff. COvere 1 fala laylight, watched vantage arkroom ed in the » it will ‘ticles of En acted te is re. t is per. race of d in the orm the plate or Without Picture, laylight plate or bromide k for WN Oxy- ntly by Reneyw- ng time oxygen | divers, akes Ee Tered to is the ) when is new me this PCat halves he user and the hinged nd-cart into a in two illus- 1d-cart f being September, 1925 New York Builds the Largest Power-Generating Station 2 tog largest electric generating station jn the world is being erected on the East River in New York City. It will have a capacity of 1,000,000 horsepower, enough to light at least 3,000,000 six- room houses. Operated at full capacity this single station would be capable of providing all of the electricity required by any state in the United States, New York excepted. It will be capable of producing 100,000 more kilowatts than the projected power development at Muscle Shoals. Imagine all of the horses in all of the cities in the United States, 2,000,000 of them, hitched to one load. Their power would just equal that of the great aggregation of power available in New York City when the new $50,000,000 plant is completed. Water from the river will be used in the station and coal will be unloaded directly into bunkers from ocean-going vessels by means of traveling towers along the waterfront. Loup chewing is the undoing of certain insects and grubs traveling from the Orient. to the United States in sacks of peanuts. A newly invented microphone intensifies the:sound of their champing and enables customs officials to detect their presence. The apparatus is used, also, in finding insect pests in stored grain and fruits. Unsinkable Rowboat May Be Folded into Compact Bundle ERE is the latest idea in folding boats. It can be rowed or paddled like a canoe and is sufficiently large so that the passengers are not cramped. The flat bottom makes the boat steady. ys Packed into a { bundle as shown \ at the right, it / \ weighs but 36 j ’ pounds. Airtight cham- bers are ar- ranged along both sides, so that the boat is unsinkable, even when it is full of water. Airtight chambers set along each side of this collapsible rowboat render it unsinkable POPULAR SCIENCE MONTHLY 65 : Small Pump Converts Auto into Fire-Engine HOUGH small in size, — this portable pump, ae which can be attached to an automobile in two minutes, will do a good day’s work, raising 100 gallons of water a minute by suction alone to the pump’s level and then spraying it a height of‘from 50 to 60 feet. ae The pump is operated by means of a belt around the rear wheel of an auto after the wheel has been jacked up. It is especially recom- mended for small towns that have no regular fire- fighting equipment or those in the neighborhood of large forests. It also is useful for pumping out cellars and ditches after an accident or a flood has caused an over- ° . = TES ~ SERS ae NS Z =. Me 2a pc - - flow of water that will not drain off quickly. Hitched by pulley to the hind wheel of an auto, this small pump is said to raise 100 gallons of water a minute New Gasoline Tiller Replaces Old “Dobbin” HIS remarkable invention consists of a one-cylinder gasoline engine built into a compact one-man machine ar- ranged to do tilling and ridging in one operation. It is claimed that this compact little machine will prepare two acres of land in an ordinary farm day. One of. its most important features is that it is so small it can be used under overhanging branches and between growing bushes where no ordinary type of plow could be used, and this is especially useful in orchards where land between the trees is utilized for growing vegetables. An Amazing New Auto ROM Poland recently came word of an astonishing sort of automobile. It is the invention of an engineer named Ker- powski, and he calls it the ‘‘Polonia,”’ after his native land. It is designed to bring about the utmost simplicity and speed in making repairs and replacements of parts. In a recent public test, two mechanics and a helper took down the motor, gear set, universal, and rear axle in 14 minutes, and had the car completely reassembled in 36 minutes additional. The car has a six- cylinder motor, develops 45 horsepower and is said to be capable of a speed of more than a mile a minute. Mouse- or Rat-Trap Is Set by Pressure of the Foot N2 ONE wants to set a mouse-trap. The little wire is fixed just right, when ‘“‘Snap!’’—once again your fingers are caught. In the illus- tration at right is shown a new safety mouse- and rat-trap, which is set with pressure cf the foot. After a rodentis caught and killed, a slight pressure on thefoot plate will release it. Thetrapismade of galvanized steel and wire. Pressure of foot will set this novel mouse-trap

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Farm and Garden, Handy Grass Trimmer Operating like a barber’s clipper, the handy little grass-trimmer shown above is designed to cut the uneven edges of lawns and to penetrate corners no ordinary lawnmower could negotiate & Lay Eke ey SVP WEE a. Abs PLN "4% oe a pot ¥ ae Ans ANA gf ye ew AWW Z POPULAR SCIENCE MONTHLY September, 1925 Some Ingenious Outdoor Ideas That Will Be Found Useful Kansas Breezes Grind Farmer’s Corn No sluggards in Kansas! Even the wind does double duty. Beside drawing water, it grinds feed for the stock of E. K. Edwards, who built the ingenious wind- mill shown above, thus saving one man’s labor daily Butter Churned by Bicycle-Power This ingenious apparatus for churning butter was rigged up by a Minnesota farmer. Raising the rear of his bicycle on wooden stilts, he ran a belt from the rear wheel to the wheel drive of the odd churn ‘*Rain-Making”’ Tower William Haight, of Wilmington Park, Calif., claims he can make rain by the manipulation of what he calls negative electric ground waves and positive waves of the atmosphere’s upper strata. His apparatus, mounted on a tower (at extreme left), is designed, he says, to reverse the natural order of electrical emanations, resulting in a pulsating current between the ground and upper strata, which in turn causes condensation of cloud moisture and brings on rain. Mr. Haight is pictured at the left For Rough Mowing At the right is a new mowing ma- chine designed to ‘“‘top”’ tall growth or to clean up a lawn after a lawn- mower. It is not intended to re- place the lawnmowe.. It is said to cut 10 times as fast as a scythe ‘ A fee Ni cui q eggs

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: September, 1925 Padlock for Park This immense golden pad- lock and key were used in the recent celebration of- ficially opening the Zion National Park, in Utah POPULAR SCIENCE MONTHLY A 22-Foot Saxophone Wanted—a musician with lung power enough to play the world’s largest saxophone that forms part of an adver- tising display for a New York musical-instrument concern. This giant jazz creator is 22 feet high and its bell is four feet in diameter. Workmen are seen hoisting it into place a Match? Have you ever seen larger matches than these? Dixie Boat- wright, popular Zieg- feld Follies girl, who is seen carrying a box of them on one shoul- der like a bundle of kindling wood, says you don’t strike them any bigger hereabout Have Supports 10 Tons The largest pneumatic tire ever made in America —64 by 14 inches—was designed for the landing gear of one of Uncle Sam’s largest planes. It will carry 20,000 pounds A Long Smoke A briar pipe 51% feet long is Lady Nicotine’s latest curiosity. It re- quires the services of a smoker and two assistants to get it really going 67 They Don’t Come Any Bigger These Oddities Claim the World’s Records for Size AN % ‘; i THANE Puzzle—Find the Man Barney Winters, of New York, boasts of a hat that would fit a giant—all straw and a yard wide at the brim

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By the use of heater-lunch- box, food is served appe- tizingly picnics. POPULAR SCIENCE MONTHLY Carry Your Own Hot-Lunch Kit UNIQUE little “traveling restaurant,”’ in- vented in France, enables you to have piping hot food instead of cold lunches at work or on It is a portable box about the size of a brief-case, easily carried on hikes or in motor-cars. In one section are oblong plates supported in a frame raised slightly above the side of the case. Small gasoline cr alcohol cube lamps under these heat the food at lunch-time. Leakproof metal lids fit over the compartments. A plate, knife, and fork are held in the other side of the valise and a thermos bottle and drinking-cup are placed in special racks. The open box forms a small table as it rests on the user’s knee, as shown. September, 1925 Ingenious Column Ruler Saves Time in a Busy Office ‘THis time-saving appliance for ruling columns consists of a grooved bragg roller set in a handle. It is provided with an absorbent swab that fits into the slot and feeds the roller with a supply of special red ink. The device is made in three sizes, for ruling one, two, or three columns, and i a great timessaver. Grass Causes Hay-Fever EVIL-GRASS, the curse of lawns in California, is the chief offender in causing hay-fever in that state, according to Dr. George Piness of Los Angeles, who has been carrying on extensive research to find out what caused the trouble. California does not have the ragweed that causes much suffering among hay- fever victims in the East, but a large number of persons are sensitive to the pollen of Bermuda grass or devil-grass. Know Your Car EMARKABLE as it may - seem, sometimes the best way to make your car ride easily is to avoid oiling the springs. This applies particularly in sections where the roads are full of ‘‘thank- you-marms” or successive de- pressions and bumps so spaced that the car acquires a forward and backward pitching motion. On such roads, an auto with well oiled springs will pitch so badly that the driver’s neck will become tired due to the constant swaying. It was once thought that failure to oil the springs caused the break- age of the spring leaves, but engineérs now claim that a dry spring’may be expected to last as long as’a well oiled one. Remember these rules if you want the maximum comfort in driving over rough roads: 1—Pump your tires only to the lowest pressure recommended for the size of tire and the weight you are carrying. 2—Fit good shock absorbers that actually apply friction during the recoil of the spring. 3—Keep your springs thoroughly oiled if the car is fitted with shock absorbers. 4—Auxiliary springs will be a help on rough surfaces. 5—Slow down or speed up if the car-starts pitching violently so as to get the speed of the car out of tune with the bumps. Climbs Steel Girders with Patent Grippers ABOVE is John E. Seaberg of Pitts- burgh, Pa., demonstrating a simple but clever device he has just invented to aid structural ironworkers in climbing steel girders. His invention is a pair of wooden clogs equipped with steel grippers New Process Makes Golf Clubs Waterproof and Hard NEW process for treating wooden golf clubs makes them waterproof and extremely hard. Heads of seasoned persimmon wood are subjected to a vacuum that extracts every particle of air and moisture from the wood, which then is impregnated with the newly discovered chemical. The club heads then are dried and hardened. Clubs treated in this manner are said to have greater driving power than other wooden clubs and not to shrink or expand with varying atmospheric conditions. Inserted face plates are not required, since the chemically treated wood is itself harder than fiber, bone, or ivory. that engage the projecting edges of the girder, making it possible to climb ag easily as if he were walking up a telegraph pole with its iron spikes. This invention, Mr. Seaberg says, saves much time. IF you have a gallstone, you pay to get rid of it, but there are people in the world who will pay as much as $50 for a good one. Chinese and Japanese are said to hang the stones about their necks to ward off disease and bad luck A packing plant in Omaha, Neb., collects the gallstones found in slaughtered steers and sends them to the Orient. Heart-Shaped Glasses Protect Eyes of Movie Actors [- IS a well known fact that moving-pic- ture actors who have made a number of “inside” pictures frequently are troubled by what is known as “‘studio eyes.”? The condition is caused by long exposure to the intense rays of the cluster lights, and frequently an actor has had to take a protracted rest to recover from such an attack. The picture below shows Claire Windsor, famous movie star, wear- ing the latest thing in “‘studio glasses,” heart-shaped to relieve their otherwise ugly appearance on the wearer. These glasses are made in diamond, square, or spade shape. The lenses are smoked to rest the wearer’s eyes as much as pos- sible. Heart-shaped smoked glasses protect tired eyes I ¢ ¢ v I

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ided the y of id ig the ) as ‘aph ion, get the or a >cks ects eerg pic- r of led The to its, ake ich ar- September, 1925 Pen with Three Points Aids Bookkeepers in Ruling HE tedious work of ruling ledgers and eash books in the small office is much simplified by an ingeniously made pen having a broad nib divided into three points like a fork. Two of the extra penpoints are quite close together, making the double line for the extreme left-hand column in a ledger. In a single stroke a whole cash column can be ruled. New nibs can be bought for the pen when the old ones are worn. 17 Y POPULAR SCIENCE MONTHLY Newest Home Trousers Press HERE have been innumerable trousers presses on the market from time to time, but the maker of the model illustrated at the right claims that his is the simplest of them all. It has no top board and not a single nut or screw goes into its construction. Pressing and stretching are accomplished in one oper- ation. The curved shape of the board is said to insure enough gentle stretching to eliminate bagginess at the knees. Sufficient pressure is obtained with one hand. WOMEN with dark hair are better automobile drivers than blondes, according to P. L. Emerson, owner of a large taxicab company in Chicago. He related this in conjunction with a_ statement made by psychologists, who found brunettes more conservative, on the whole, than fair-haired persons. One-Piece Tennis Suit Gives a Longer Reach ERHAPS it was the comfort of his swimming-suit or cover-alls that inspired Mr. P. Mundet, a Frenchman, to invent a similar type of suit for playing tennis. It is in one piece and in all except color and length of sleeves re- sembles a cover-all. When making long reaches or twisting for a back stroke, a belt about the waist is noticeably restrictive, while a loose, one-piece tennis suit, opening down the middle front, brings comfort, itis claimed, as well as more ease in playing. Years Ahead in Knowledge I THINK the magazine wonderful and do not see how a family with growing chil- dren could do without it. It puts people who read it years ahead of people who do not.—C. W. C., Franklin, Pa. Smoking-Tube Is Latest Fad for Fastidious Women T’S a headlight when the cigarette is lighted. A vacuum cup holds the cigarette firmly to the rim of the smoker’s hat, so that she can smoke with ease and comfort. The holder with rubber tube can be adapted for use while reading in bed, riding in an automobile, or playing cards. Smoking a cigarette by long distance One-piece tennis suit is comfortable Scientist Says Meat-Eaters Live Longer than Vegetarians EGETARIANS received a blow when Prof. James R. Slonaker, a Leland Stanford University physiologist, de- clared recently that meat-eaters live just as long as their abstaining brothers, in fact, longer. For eight years he has been experimenting with meat and vegetable diets on rats and now is applying his results to human beings. When the rats were fed vegetables only, the span of their lives, he found, was shortened, in males 33 per cent; in females, 40 per cent. Males lost 35 per cent weight, and females from 25 to 28 per cent. By the third generation the non-meat-eaters lost the power of re- production, indicating that vegetables lack something necessary to health. THE greatest underground electric power cable ever installed is to be put in New York City to protect the city in fire-fighting. It will be operated at 132,000 volts and will link together the generative stations of the New York Edison Company with its subsidiaries, reducing the possibility of interruption to the Fire Department’s pumping during a fire. How Much Do YOU Know about Science? ‘THE following questions, dealing with the common facts of sci- ence, are the kind that PoPULAR SCIENCE MONTHLY receives daily. Look them over and see how many of them you can answer. Don’t let your brain get lazy. Give it the sort of stimulant that these questions offer, and you will find your faculties sharpened and your appreciation of the world’s natural wonders greatly enlarged. Now turn to page 135 and see what percentage of the 12 questions you were able to answer correctly. 1. Why do liquids rise in a straw through which you drink? 2. Why do the men near the guns on a battleship open their moutis when the guns are fired? 3. What is invisible ink? 4. How far does the earth move each day in its journey around the sun? 5. Where does the sand on the seashore come from? 6. What are sun-spots? 7. Why does hydrogen peroxide bleach the hair? 8. Why is there no air inside an e"ectric-lamp bulb? 9. how does a whale keep warm? 10. Why must a vacuum-tube filament be hot? 11. What is the tallest tree? 12. Why does your face get white when you are frightened?

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POPULAR SCIENCE MONTHLY September, 1925 What Batteries Are Best for Your Radio SetP How to Save Money and Trouble by Making the Right Choice sets require a supply of electric current to operate them. And if we are to get the kind of radio reception we want, the sources from which we draw current for our radio sets must be capable of delivering electrical energy in a steady, uniform fiow for hours at a time without appreciable change in voltage. Furthermore, we need two, and in some eases three, different sources of ‘current supply. The filaments of the tubes must be heated, electrical pressure must be applied to the plates of the tubes, and in circuits where it is needed we also must use a third source of energy to keep the grids of the tubes at the proper potential. Coupled with our desire to secure per- fect reception is the need for obtaining satisfactory results at the lowest possible cost and at a minimum of trouble. And it is this matter of trouble and expense that sometimes makes the problem of current supply a decidedly vexing one. Obviously, it does not bother the man who can afford to go to his dealer and arrange with him to see that the radio set always is operating prop- erly, regardless of expense. For the beginner the question is complicated still further by the fact that there are three types of vacuum tubes in common use today, and each type requires different pressure and volume of current to heat the filament. Vs radio receivers except crystal I‘ SEEMS logical to de- cide on the type of tube first, and then to study the various ways in which cur- rent may be supplied to the filament circuit. Most people have found that, all other conditions being equal, the tubes that use one-quarter ampere apiece at a pressure of five volts will give greater vol- ume than the tubes ordi- narily sold for operation with dry cells. In addition, the larger tubes seem to run more uniform in charac- teristics. There is little choice between the two types of dry-cell tubes on the score of operating results, although there is a slight difference in economy. Three dry cells in series are required to operate the .06-ampere dry-cell tube as against one dry cell for the one-quarter-ampere tube. However, the three dry cells last more than three times as long as the single cell used on the other tube. The mere fact that a certain type of tube is called a “storage-battery tube’ and that another type is called a “dry- ORY-CELL A BATTERY STORAGE A BATTERY FOR DRY-CELL TUBES By John Carr cell tube,’’ does not mean that the fila- ments of the tubes necessarily must be heated with current from any particular kind of battery. Storage-battery tubes can be operated from dry cells, and vice versa. It is merely a question of selecting the source of current that will prove most economical of your time and money in your own particular case. Take, for instance, the typical case of a superheterodyne receiver built for use GRID f CONNECTED wiTH |) TUNING CIRCUIT | OR TRANSFORMER | CONNECTED WITH A BATTERY AND TUNING CIRCUIT The Sources of Current Supply At the left are the A batteries, ranging from the single dry-cell to the standard six-volt storage battery. At the right are the various types of B batteries and B-battery eliminators in common use. The small dry-cell B battery at the top of the column is useful for portable sets, but is not economical for regular use with dry-cell tubes. Assume that several members of the family use it almost daily, so that the total number of hours of operation a month may be well above the century mark. Under such condi- tions it is easy enough to prove that a set of storage batteries to supply both A and SMALL ORY-CELL B BATTERY B current would result in marked economy + of operation. On the other hand, the owner of the receiver might: figure that the additional care and attention required by the storage batteries would more than offset the saving in money. You can see, therefore, that the per- sonal equation enters into the problem and is usually the deciding factor. AMONG beginners particularly, there seems to be considerable confusion about the relative merits of dry cells, storage batteries, and B-battery elim- inators in giving satisfactory results in the operation of the radio receiver. This confusion has been caused mainly by conflicting claims of the manufacturers of the different sources of current supply. As a matter of fact, there is no dif- ference whatever between the operation of a radio receiver using dry cells and the same set supplied by storage bat- teries, provided, of course, that the dry cells are reasonably new and the storage batteries in good condition and properly charged. Old dry cells that are nearly exhausted sometimes will produce a lot of noises that sound like static. Storage batteries also of- fend in this respect if the connections become cor- roded. If you are troubled with noises in your receiver, however, merely buying new batteries or another type of battery is not nec- essarily a cure-all. A de- fective tube or a bad con- nection in your receiver may be entirely respon- sible, or the noise may not originate in your equip- ment at all. Some piece of electrical machinery near by may be radiating ALTernamne energy that affects your receiver like static. GB BATTERY ELIMINATOR ‘ FOR USE ON A STORAGE battery requires recharging at regular intervals, depending on how much you use your receiver. At least once a month the level of the solution in the battery should be inspected and distilled water added. This applies to both storage- A and storage-B batteries of either lead or alkaline type. If electric-light current is available in your home, recharging the storage bat- tery is simple. A variety of chargers are on the market. Some use tubes, others rectify electrolytically, while still others are of the vibrating reed type. The Popular Science Institute of Standards has tested and approved a number of these devices, and any of the approved Sept type alral char: the : spec! terie ber « able his 0 all man and weel on ; have up t ting is 1 thro littl you batt once weel get so t regu ever you in. not} a 4 batt For outf hou) men outf amy amy not rate ina whe of t volt on par: use use cell: alsc are so | bat and tag con eve five will will itr con ply you hot of 1 day the

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~ _ BON CO mw 8 —a SNS OS Fmt 8 S— ea. Ur September, 1925 will give you excellent service. Some of the approved chargers are so arranged that they are capable of re- charging either A or B batteries with the same apparatus. Others are made specially for A batteries or for B bat- ‘Storage A batteries are made in a num- per of sizes and the beginner often is un- able to decide which size will be best for his own use. The answer all depends on how POPULAR SCIENCE MONTHLY radio set is not used, but, on the other hand, the set will be run all afternoon by one member of the family and until the wee small hours by the owner. We also have to assume that the set consumes a definite amount of current— say 25 milliamperes. This is more than some five-tube receivers use, and less than most of the “‘superhets.” Under such conditions, an extra large 71 Before deciding on whether storage B batteries are a worth-while investment for you, be sure to study Mr. Senauke’s article on page 72 of this issue, explaining the important part the C battery plays in cutting down the amount of current. drawn from the B battery. Of the B-battery eliminators on the market today, some are excellent; others do not give results comparable with batteries. The B-battery eliimina- aaee ; tor should be considered many tubes are in your set and how many hours a week you expect to use it on an average. If you have your charger wired up to switches so that put- ting the battery on charge is merely a matter of throwing aswitch, it makes little difference whether you have to charge the battery every week or only once every two or three weeks. ENERALLY = speak- ing, it is advisable to get a battery large enough so that you can charge it regularly once a week—say every Saturday night after | alien neil pie experiments can be performed in the home con- struction of storage B batteries. out of old ink-bottles and pieces of lead wire with a solution of sul- The illustration shows such a battery built by John A. Clark, head of the Physics Department of Alexander Hamilton High School, New York, for use in-his class demonstrations. Such a battery will produce a voltage of two volts a cell, but the home constructor usually finds to his dismay that the capacity of the battery he has built is so small that it will run the radio receiver for only a few minutes before it is discharged completely you are through listening in. For a small set using not more than three tubes, a 40- or 60-ampere-hour battery issufficiently large. For a five- to eight-tube outfit an 80-to 100-ampere- hour battery isample. Re- Builds B Battery from Old Ink- Bottles phuric acid and water. It is possible to build a battery on adollars-and-cents basis as a source of current sup- ply. Any claim that a B- battery eliminator will give you better reception than is possible with batteries obviously is absurd. Good batteries will give you a perfect source of current supply, and all that any B-battery eliminator can hope to do is to equal the results obtainable with batteries. HE advantages of a good B-battery elim- inator are apparent. Once installed. it will last indefi- nitely and will require no attention except the occa- sional addition of distilled water to the electrolytic types and the renewal of tubes in the models that use tubes to rectify the alternating current. This matter of tubes for use in B-battery eliminators is member that an eight-tube outfit using one-quarter- ampere tubes draws only a total of two amperes, and this amount of current will not prove an injuriously rapid discharge rate for even a 40-ampere-hour battery. Storage-battery operation of the tubes _in any receiver designed for use with the dry-cell tubes is practical also for the man who does not mind the additional trouble of taking care of the battery. For 1%- volt outfits that are arranged to operate on a number of dry cells connected in parallel, a single-cell storage battery is used, while a two-cell storage battery is used for the tubes that require three dry cells connected in series. i Bisa advantages of a storage-battery source of supply for your B current also depend on the number of tubes you are using. A one- or two-tube outfit uses so little current that the large dry-cell B batteries often last for more than a year, and there is certainly no possible advan- tage in a storage B battery under these conditions. With multi-tube sets, how- ever, it is another story. If you have a five-tube receiver or a “‘superhet,’’ and use it considerably, the storage B battery will prove an economy, provided you are willing to give it the care and recharging it requires. In such a case it is easy to make a direct comparison of the actual expense of sup- plying B-battery current to your set if you will assume some definite number of hours a day as representing the amount of time the set is in use. Three hours a day should be a fair average. Of course, there will be a number of days when the B battery of the dry-cell type, consisting of two of the 45-volt heavy-duty blocks, will last for about a third of a year. Such a battery will cost in the neighborhood of seven dollars, or a total expense for the year of $21 for B-battery current. A suitable storage battery for such service will cost around $40 and will last five years or even longer if exceptionally well cared for. This amounts to about eight dollars a year, and to this expense must be added the cost of recharging, which figures out at approximately $2.50 if you assume that the battery will need a 10-hour charge at least once in every two weeks to keep it in good condition and you have a reasonably efficient A- battery charger that can be used also to recharge the B battery. WO types of storage B batteries are in general use today—the acid type and the alkaline type. It is claimed for the latter that they will stand more abuse in the way of allowing them to stand discharged, or too rapid charging. While this is true, the lead-acid type maintains its voltage practic-lly unchanged until nearly discharged. Another claimed ad- vantage of the alkaline type is that since it contains no acid it cannot damage the rugs if, perchance, any of the solution is spilled. Thisclaimseemsto beunfounded, for the caustic potash it uses will chew holes in a rug just about as quickly as the sulphuric acid in the lead type. Neither type will give you any trouble in this respect if ordinary precautions are taken. still causing some trouble because the ordinary radio tube does not have a sufficient current- carrying capacity to operate some of the larger receivers. Special tubes adapted to this particular use already are appear- ing, and these new tubes, of course, can be used in any of the standard B eliminators. A B-battery eliminator will not work properly always on every type of circuit and under every condition. If you de- cide to buy the B-battery eliminator, be sure to have your dealer demonstrate it with the set you intend to use. Cloth from String Beans A PROCESS for making coarse cloth from the fibers of stringsbeans was perfected recently for commeffial use in Austria. The bean shells are treated like hemp, and the fiber that results can be spun, making a hard but strong yarn. This new material is expected to offer competition to hempen products. It is adaptable for making materials for which cotton has been used heretofore, and it can be used in making carpets, curtains, upholstery, and saddlery after it has been bleached properly and printed. Milky Water Appears in Norway PERSONS living on the shores of Sog- nefjord, the longest fjord in. Norway, were startled greatly by a strange phe- nomenon. The water, which is usually dark and clear, suddenly became milky and opaque. All of the fish in the water disappeared. No explanation has been found so far for this weird occurrence.

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72 POPULAR SCIENCE MONTHLY September, 1925 When Is a C Battery Worth Whiler Remarkable Tests Reveal New Facts about Quality HERE are, probably, thousands of perfectly good C batteries now resting unused in an equal number of homes where radio sets are installed. The owners of these batteries bought them after reading somewhere that there would be a wonderful increase in volume and quality of their reception merely by the addition of a C battery to the circuit. And then, when the promised advantages did not show up in loudspeaker results, the disgusted radio fans characterized what they had read as bunkum and dis- carded the C batteries. The trouble is, of course, that the real advantages of a C battery By Alexander Senauke, M.E., E.E. Radio Engineer, Popular Science Institute of Standards then with one connected in the circuit. The results of these tests have been plotted in graphic curves as shown at foot of the page. The ideal curve for an audio- frequency transformer really should not be a curve at all. It should be a straight line. No transformer is absolutely per- fect, so that the quality of a transformer as an audio amplifier can be determined , by noting how much the - tendency to damp out these frequencies As far as volume is concerned, the C battery helps much more with a hig! grade transformer than it does with a low grade one. This is especially true if two stages of amplification are used where t} cumulative effects of irregularities in th: amplification curve are magnified great}, From the standpoint of economy of current in the B circuit, the use of a ( battery always is desirable. A standard type of storage-battery vacuum tube used in the conventional audio-amplifier circuit with 90 volts of B battery draws about four milliamperes. When a C battery is introduced in do not always show up in the loudspeaker. For that reason the Popular Science Institute of Stan- dards has just completed a series of experiments de- signed to show just when and how the use of a C battery benefits the radio fan. We studied the use of a C battery in an audio- amplifier circuit from three standpoints: First, to find out what effect, if any, the C battery has on quality of reproduction without regard to volume; second, what the C_ bat- tery does to the volume and, lastly, what value a C battery has in increas- ing the life of the B bat- tery by cutting down the amount of current used in the plate or B circuit. An amazing fact developed from our tests was that the value of a C battery in a circuit largely on the quality of audio transformers used. In our test we used two types of audio transformers. One was a low priced, low quality make, and the other was a high priced type considered one of the best. depends The transformers were connected to couple two storage-battery-type amplifier tubes of standard make in the conven- tional audio-amplifier circuit. The volt- age amplification for one stage, in- cluding the transformer and one tube, was measured through the range of from 150 to 3000 evcles with a normal signal, first without the C battery and \ Plate Current deviates from a amplification straight line. From the results of our tests it appears that a cheap, poor quality audio transformer actually may give better re- production of voice or music when used curve without any C battery, providing, of course, that the signal strength is low enough so that the tube is not overloaded. The diagram at the left shows this. Now look at the right-hand diagram, and you will see what happens where a high grade audio amplifier is used. In this case the quality is just as good with the C battery as without it; in fact, the slight increase in amplification at the higher frequencies may actually improve the quality of the music from many Mr. Senauke recording the difference in the total plate-current of a receiver when used with and without a C battery the circuit, this current flow from the B battery is cut down to about 114 milliamperes, so that in the five-tube receiver em- ploying two stages of audio amplification ther will be a saving of five milliamperes in B-battery current. This amount of current saved may be as much as from 25 to 30 per cent of the total current drawn from the B battery and may prolong their life as much as 60 or 70 per cent When storage B batter- ies are used, the saving in current is relatively un- important because storag: B batteries must be re- charged every so often. To sum up, our tests show that the C battery is always worth while from the standpoint of economy and that the volume always is increased, at least to some extent. This increase in signal strength is obtained without any falling off in quality except when low grade audio transformers are used, in which case the quality actually may be poorer with the C battery than without it. Testing HESE tests were made on a signal of normal strength that did not over- load the vacuum tube. When a strong signal is being received, the C battery has another advantage. By negatively biasing the grid, the plate-current variations are kept below saturation point of the tube The C battery, therefore, helps you get 1800 FREQUENCY 600 1200 LOW: QUALITY TRANS. 2400 types of loudspeakers that have a volume with the minimum distortion. . iO pace ; oe i. mg gre ngecsienetesinngieeesecaiiarsee 7 —y How C Battery 23 TTT HEACHSRReeeae ae eae Affects Quality 2 20,111 S22P ERO EERE cee Peer BER ERE RET The curves at the x ——|—|- B BATTERY=90 VOLI> CA f | left show how the use of a C battery —= 18 Tc BATTERY-- 45VOU'? J 7 | may actually de- | 16 SORRSHEARE RRR RS grade the quality 2 4, {|_| | | |B BATTERY= 90VOLTS| | ase when used with a ne 4-4 (NO C BATTERY )-+ po poor audio trans- ie “ nhs CCoeet SS ean EE former. With a Es BREE eS ST | Bn eee k tit tts CI high class trans- re) 4 oe ee HIGH) QUALITY, TRANS. [ 1 | former the volume 7 9 Je Ht Be | | | Bit ae | 4 Lj is increased with- ‘ | j ia Li] Ree! im out affecting qual- ity (shown at right) 3000 1800 FREQUENCY 600 1200 September, | = Horse A remarka tation bui bile wa: cast the ] Park, N. Y from the picked up | broadcast Rac New ° trying t + out make to all m head at the Sage is iomet I novel right w lder, an iper Co! plece between tl the A

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September, 1925 POPULAR SCIENCE MONTHLY » Horse Races Broadcast A remarkable portable broadcasting station built into a standard auto- bile was used recently to broad- st the horse races at Belmont Park, N. Y. The short-wave signals from the portable station were picked up by station WBOQ and re- broadcast on regular wave lengths Builds Unique Radio Rutledge Mayo, of New York City, has built a receiver using.the new AC tubes and a B-battery elimi- nator of his own design Radio Calls Police New York Police Department is trying out a wonderful new device that makes it possible to flash sig- ls to all the police stations direct m headquarters. A light flashing at the receiving set warns that a sage is about to be transmitted llomemade Loudspeaker The novel cone-type loudspeaker at he right was made from a candlestick lder, an old-fashioned lamp-shade, iper cone, and a loudspeaker unit. A piece of bus wire was fastened between the center of the diaphragm the center of the paper cone u 73 Radio Sparks Flashes of Progress Made by Fan and Manufacturer A New Midget Unusually small midget variable condensers now are available to the ra- dio fan for Vernier tuning. Very small variable condensers of this type also are useful as balancing condensers. The construction is the same as that used in larger condensers of the grounded metal-end platetype Huge Condenser The fixed condenser il- lustrated above now is being installed by an American firm at Rugby, England, for use with the transmitter of the power- ful radio station at that point. The tremendous size of this monster con- denser can be judged by comparing it with the small radio condenser in the girl’s hand. Every detail of the installation of such a condenser must be done most carefully

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This view of the wa nected with the variable condenser HE only trouble with a wave trap or interference eliminator, as it is sometimes called, is that most radio fans expect such a device to perform miracles. And then, the results are not as expected, the device is promptly relegated to the scrap pile, even if the failure of the wave trap really is due to an incorrect when hook-up Properly used, a well made wave trap often will help a great deal in eliminating from local stations. But you building the wave trap described here, to experiment interference must be prepared, in a bit until you get it working correctly with your own radio receiver and under your own particular conditions This wave trap, which has been tested approved by the Popular Institute of Standards, can be for use with any type of Science and adapted radio receiver that operates on an outdoor antenna. The circuit used in the receiver has con- siderable effect on the wave trap. \ single-circuit receiver, for instance, re- quires that the trap be used in the series On the other hand, a wave } pe used either in connection trap car series or parallel with the more selective types of } three ecircult re- receivers such as the generative, neutrodyne, and _ so forth Whether the series or parallel] CO ectio W be best in anv par ticular Ca bye dete Y ined oO! I T1¢ I [t ( ye ds oO ? ( ( et sucl t he nat l I t "ePCOELVE the + 4. 1 th pow tl t f L¢ ter! . tne » | | ‘ he ‘ } + ( W im N Le 1 you one piece oft ap- condenser, and the uu will have an odd in a corner of the icely. As shown built he wave trap was ve trap shows how the upper coil B is con- Notice is provided for additional turns on the lower coil A POPULAR SCIENCE MONTHLY How to To with a composition panel and a wooden base board in the con- ventional manner, but you can take almost any liberties you like withthe arrangement so long as you are careful to keep the variable condenser or any other metal part away from the open ends of the coil. The capacity of the variable condenser is also relatively unimportant. You can use a 138-plate, 17-plate or 23-plate type. Of course, you must wind the number of turns in coil B that will enable you to tune the wave trap to the wave of the interfering station. If you use a coil form three inches in diameter and No. 22 double silk-covered wire, wind about 70 turns of wire for coil B if used with a 13- plate condenser. Sixty turns will be about right for a 17-plate. condenser, and 50 turns if you use the 23-plate type. You will have to wind coil A to suit the particular conditions under which you use the wave trap. The model shown here has nine turns of wire spaced one-quarter inch from coil B. It is best, since the number of turns in coil A may have to be changed, to wind on more turns than specified. Itis a relatively simple matter to take off turns from any coil, but if you find it to add turns, the only really good way is to rewind the whole coil in unsightly soldered that ample space if needed necessary order to avoid joints in the wire. ship = HT Another view, showing how lower coil A is connected with the panel binding posts September, 1925 Build and Use A Simple Wave [Trap Stop Radio By Alfred P. Lane Interference After you have mounted the complete coil, the variable condenser, and two binding posts, the wiring will take only a few minutes. Connect the ends of coil A with the two binding posts and then con- nect one end of coil B with the binding post on the variable condenser that is connected with the rotary plates of the condenser. The other end of coil B goes to the binding post on the variable con- denser that is connected with the station- ary plates. The two ways in which the wave trap can be connected with your receiver are shown in the diagram. The best way can be found only by experiment. In many cases the radio fan is troubled | (alae b sasilalacs | | e+e ANT ( @| -1@ ANT. 1| | ©) ¢|E}}| ©4 | @4eGRo. } ev lec}! WAVE | RECEIVER WAVE [RECEIVER TRAP TRAP | Ferd = Grd. PARALLEL SERIES CONNECTIO CONNECTION ; Above: Pictoria’ wiring diagram snowing hook up of the wave trap. Below: Two ways of connecting wave trap with receiving set with interference from one_ par- ticular station that is so near and so powerful that it even may inter- fere with the reception of other local stations operating on wave lengths 20 meters or more higher or lower than that used by the stati from which reception is desired When the wave trap is used in the series connection shown above, it is tuned to the wave of thi station to be eliminated and all other stations on higher and lower wave lengths still can be received, although the signal strength of the stations nearest the interfering station will be cut down to some extent. Thus the series arrange- ment is best for use when one station is Continued on page 134) September, 1925 Ne Ac Easily Attac Air ent arounc outside rifugal fot jetachable Filler G This ne of the regular fil and make simple matter \ tank Rubber Ba Steady C: + A A tis sh le de ttinz d xcess recoil bute: to the Ob x cars roads. ly tre straps lastened to by cl

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September, 1925 trifugal force Filler Gage for Ford Below: This new gage takes the place of the regular filler cap on the gasoline tank and makes refilling the tan a simple matter without removing seat Easily Attached Air Cleaner Above: Air enters at the rear and is whirled around by vanes. i thrown outside of the air column by the detachable box, held by a wire POPULAR SCIENCE MONTHLY Newest Auto Improvements Accessories that Add to the Motorist’s Comfort Automatic Tire Rack A large spring is con- cealed in the hollow tube that forms the suppcrt of the tire rack illustrated at right. Thisspringbal- ances the weight of a heavy tire so that a driver can exchange spare and punctured tires without effort ICH BOX Steady Car At richt is shown ple device tting down xcessive recoil that ibutes so to the dis- of riding t cars over roads. The ly treated : Straps are ‘fastened to the Tame by clamps Rubber Bands Lunch-Box de Luxe The remarkable chest above holds 35 pounds of ice and enough food for several meals. In fact, with the addition of a stove, it supplies practi cally everything needed for a portable kitchen. There are thermos tanks for hot or cold liquids Ae Pu 4 é ’ Pedal Extension Ford owners wearing wide shoes have difficulty in work- ing the reverse pedal without interfering with the other pedals. This device solves the problem simply, as shown Auto-License Holder This license holder is clamped on the steering column and the license can be read through the celluloid cover as the cylinder revolves on its axis

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POPULAR SCIENCE MONTHLY September, 1925 The Tricks in Shifting Gears Gus, the Kxpert Mechanic, Gives Some Sound Advice to the Beginner Who Comes to Grief on a Hill US WILSON, half owner and chief mechanic of the Model Garage, always claimed that he could tell by the sound of the telephone bell when the party at the other end of the wire was in serious difficulties. It was not strange then, that he chucked a wrench back into the toolkit and stood up with a yard-long scowl on his face as the telephone rang y : insist ly. ringing stopped abruptly, and a few seconds later Joe Clark, his partner, popped out of the office where he track tomers’ ac “Ding bust it! Joe. “Al Tayl r from Ridge sharply and_ insistently The pilal} kept of cus- ‘ount sand did the bookkeeping. exploded By Martin Bunn rupted Gus. “TI have to shift got rattled t into second. it, the car started rolling backward here you are!”’ Taylor appeared surprised and a bit crestfallen. “Then it was my fault? Gosh, I thought with the transmission, and I was so rattled I never thought to put on the brake until it was something had gone wrong PIPPI iiiiiiiiiiiiiiiii iii iit iti i is is where you would I] suppose you and couldn’t get the gearshift o work, and while you were fussing with —and corey ‘Tell me, Gus, what did I do wrong” Taylor asked as they drove carefully doy the hill in the direction of town. ‘““Well—no offense meant, Mr. Taylo; but you are a new driver, and almog everything a new driver does is wr The thing you did is one that often tring up the man who hasn’t had a whole lot of experience.” “Go on,” said Taylor, “you can’t } my feelings. I thought I was the x thing as a driver. Now I know I’m not so go right ahead, and maybe next tin I won’t be so dumb.” “You see, Mr. Taylor, gear- shifting is mostly a mat- Street has got himself all mussed up down at the bottom of Smoke Hill and he wants to be hauled in right away. Can we make it?” “Make it?’’ said Gus, dis- gustedly. “Sure wecan. But how about this job for Mrs. Jenkins? You know we 1: promised itthismorning. Can you lay off those bills long e! ug I - Sure,” ‘a riz ned J o¢ “That where I shine as mechanic up jobs finishir gy when all hard work is done. es answered with an un- : 1] oa 5 e ] } Js intelligible grunt, cranked } up the wrecking truck, and WTITITTITITITITITIT TLL rattled out of the garage with the mudguards flapping like the wings of a bedraggled and much frightened chicken. The was built for . 1 ’ service, not for looks Smoke Hil yout three miles south of town, was com 1. monly spoken of by motorists | on as a “‘cork-puller.’ ‘ sharp turn at the bottom prevented | : ’ enance ot rushing tne grade, which was mild enough for the first hundred yards. And the ease with which this part of the hil 2. ll could be negoti- ] ited proved the undoing of the 3. : inexperienced motorist, for it ecame gradually steeper and e WTTTTITITITITITILILL LLL | steeper until, near the top, the : prTrade Was SO that le cal | 4. ( l | l re 1f cnang first ing to see l or even first G found ib halfv up His eat “ v 0 th vad the cry } in ] ] rice rear wher 1 t a large oak tree testified »y the cause ¢ ne atc dent l mot I qd over oO tne tru is Gus applied the brakes and begar volubly and excited to explain just how it happened ‘No need to go into details, Mr. Taylor. J can see how you got into trouble,” inter- you are shifting from first to second or from second to third speeds. | j the seci gone US says— Always take your foot the accelerator second to third, that you accelerator while S. Never try Wait till it pletely. Avoid speeding up car in first nd before the car has shift to 6. Make more than 10 feet. exactly the kind from bricant specified from maker of the car, After shifting to second or sure lo not press the again until the clutch is fully engaged. to shift in Keep your foot on the to reverse gear when the accelerator when you shift to a lower gear on a hill. car is traveling forward. stops com- sure that transmission case is filled to the proper level with by the STITT IIIT iiiiiiiiiiii iti titi titi iii it) too late. Now I nice, fat suppose Ill have repair bill,” Gus backed the towing it. In a few minutes the two men had every- thing shivshape, and when Gus cranked the winch, the rear end of the damaged car a perfectly even keel. left the ground on he added ruefully truck into position to hoist the rear end of the ear preparatory to ter of practice and knowing what happens inside the trans. mission case when you work the lever,’ said Gus. ‘‘Als ‘ars are just like horses. You must be wise to the particular whims of the critter you hap- pen to be driving because } two are exactly alike. why a man who can handk one car in fine style ofte = peevishly. ‘‘Nobody MPP quietly! I snap ’em in befor they get a chance to grate! that is just where you mak your big mistake. You 7em in,’ as you tive speeds of the gears y are trying to get into mes! and everything goes fine and cause the difference in speeds too much. Then they simp) refuse to snap in, and you e! up by trying to push over: two-foot tree. You oughtt be thankful the tree was ther to stop you. You might hav had a doctor’s bill to pay! the bargain!”’ Taylor shivered involu tarily. ““That’s a pleasant tho he said, more humbly. “G I haven’t any pro id.”’ the lu- right & PTTL warewens Gus said nothing for seconds, for they were ng and the wreckili with its trailing load claimed |! undivided attention. proaching a crossing truck ‘Look at that fellow there who is waiting for the trolley,’ he exclaimed sudden “Watch him when he tries to jump 0 See, he stood still and the trolley near! pulled his arm out by the roots. “There's a good example of what hal makes noises like a beginner when he is driving another make.” UH,” said Taylor can say that I can’t shift gears “Sure,’”’ Gus went on; “and say, with- out any regard for the rela- dandy until you get caught be September, 19: pens when q snapping the: two gears are go i] with a. they won't g happened to | the trolley ec yank on his a in the directi 7 )U kno ever in f mobile turns tion to the sp gears are in | out the clute from the gea clutch that is the gears ju: keeps on tur means you hz out some Wa down when y ing trom a to a higher speed it up changing fro speed to a “Sounds suid Taylo “The man me how to d run off a tal like that, b unde yapply it t tomobile.”’ ‘All right, answered, “‘ in a rule-of- Just remem! your foot off to a higher g shift to a lov cars, because makes the fr lown with t! that one sim wat out f you can get ‘O F COU ference road whethe mission out level ground hill, it’s an had been a b today!” “Oh, don’t a muttonhea just } WwW mM this hill we’r can get it th ; od id watch earef second about Taylor ke leet. When dow went pedal just f lutch, and be ir iever W au maine the otor Spe Gus e r 1 the of el: m ee, tha fayior admi ata the we Gus’s wri

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September, 1925 pens when you try to shift gears by snapping them in. If the speeds of the two gears are somewhere near alike, they go in with a jerk. If they are not, then they won’t go in at all, and that’s what happened to you. That man who hopped the trolley could have saved himself the yank on his arm if he had turned and run in the direction the car was going.

oN know, cf course, that with the ever in first gear the motor in an auto- mobile turns over much faster in propor- tion to the speed of the car than when the gears are in high. Now, when you throw out the clutch, the motor is disconnected from the gearbox, but the section of the clutch that is fastened to the gears just naturally keeps on turning. That means you have to figure out some way to slow it down when you are shift- ing from a lower speed to a higher one, or to speed it up if you are changing from a higher to a lower one.” “Sounds familiar,” said Taylor, smiling. “The man who taught : me how to drive used to : run off a talk something Pe ii but I never ike that, could understand how Nee spe i

vio fy 10 a] ly it to driving an < rs automobile.”’ * “All right, then,’’ Gus answered, “‘let’s put it in a rule-of-thumb way. Just remember one simple rule: Take your foot off the throttle when you shift toa higher gear and keep it on when you shift to a lower one. This works on most cars, because the slight drag in the clutch makes the free part of it speed up or slow down with the engine. If you remember that one simple rule, then all you have to ane ° ° ° S watch out for is the time interval, and the you can get that by practice. ela- ‘“ apa - = e ° Kk COURSE, it doesn’t make any dif- a ference to other automobilists on the road whether you tear the whole trans- mission out or not, so long as you are on dis level ground, but if you are on a steep a hill, it’s another story. Suppose there a had been a bunch of cars right behind you on A today!” ty “Oh, don’t rub it in,” said Taylor. “I’m nen 2 muttonhead all right. But suppose you ~~ just show me how it ought to be done on ay this hill we’re coming to. Then maybe I can get it through my head right.” 5s “Good idea,” said Gus. “Now you ii watch carefully. I'll have to shift into iit second about 100 feet from the bottom.” Taylor kept his eyes glued on Gus’s When the engine began to slow up, went the left foot on the clutch pedal just far enough to disengage the and almost simultaneously the lever went into neutral. The right mained on the throttle and when he motor had attained just the right Gus eased the lever into second and vgeor Beal ¢ +

released the clutch pedal without a sus- is Picion of clash or jerk. aril _ Gee, that was as smooth as silk,’ said Taylor admiringly. “It looks like nothing hap at all the way you do it.” Gus’s wrinkled face creased in a smile.

POPULAR SCIENCE MONTHLY “Just like everything else, Mr. Taylor; it’s easy when you know how. As far as auto transmissions go, you can make one last at least twice as long if you treat it right.”’ A few minutes more and they were in the garage, and Gus busied himself ar- ranging blocks so that the axle would be supported when the car was lowered.

“How soon will the old boat be ready again?” Taylor asked. “Well,” said Gus, with a quick glance around the garage to check up on the jobs that should be finished before Taylor’s, “about Thursday afternoon, I guess—yes, I’ll promise it by then. I suppose you will steer clear of Smoke Hill after this,’’ he added, with a twinkle in his eye. “No, sir!” said Taylor. ‘I’m going up that hill if it’s the last act of my life!’ “Better get in some practice on level ground first, then,” said Gus; ‘‘and, by the way, Mr. Taylor, if you really want to get into the expert class as a driver you might like to know how to do the ‘double clutch.’ ”’ “ll bite,” said Taylor, looking puzzled. “What is it—a joke?” “Double clutching is no joke,’’ answered Gus. “It’s something that most auto drivers know nothing about, yet it cer- tainly is a good thing to know if you hap-

Do You Know Gus and Joe? HESE two interesting pro- prietors of the Model Ga- rage appear every month in POPULAR SCIENCE MONTHLY: If you haven’t met them, now’s the time to get acquaint- ed. You’ll find Mr. Bunn’s stories not only highly instruc- tive, but entertaining. Next month Gus and Joe will give you some valuable new tips about tires.

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Did You Ever Do This? The beginner who gets when he fails in the shift from high to second gear on a hill and begins rolling ward, endangers himself and others 77 pen to want to make the other fellow eat the dust on a bad hill.” Taylor was interested immediately. “Fine!”’ he said. ‘“‘Give me all the dope onthat. I never did like the taste of dust anyway!”’ “T don’t know whether I ought to tell you or not, seeing as how you haven’t mastered the regular way of shifting gears yet,’ Gus began. “However, if you'll promise not to blame me if you rip out the transmission trying it, I’ll explain double clutching. " REMEMBER how I shifted into secs ond on that hill? You noticed, of course, that I waited till the old bus had slowed down quite a bit before I tried to shift. Now, if you were trying to race a man up that hill, you naturally wouldn’t want to wait till the car slowed down; you would want to make the shift while the car was still going good and fast. “The only way you can drop from high into second when you are going fast is to use the double clutch. Otherwise you would be almost sure to make a lot of grinding noises. “Here is how you do the double clutch: The minute the car starts to slow down in high, jam your foot on the clutch pedal and throw the gear- shift lever into neutral. Keep the ac- celerator pressed down hard. Of course, the second the clutch is thrown out and the load of the car is taken off, the motor will start to race to beat the band. With gearshift lever still in neutral, let the clutch in quickly, push down on the clutch pedal again right away, then immediately throw the speed lever into second and let the clutch in again. “YV HAT happens is that while the gear lever is in neutral, the gears you intend to mesh are speeded up by letting the clutch in so that when you push out the clutch and throw her into second there will be practically no clash. That is, if you get the timing right. The only way you can get that is to practice.” Taylor threw up his hands in despair. “‘Gosh!” he exclaimed, as he turned to go; ‘nothing doing on that for me. Guess I'll stick to plain driving. I can’t afford a new transmission just for the pleasure of beating some bird up a hill.” “Drat it!’ mumbled Gus to himself as he stared after laylor’s retreating form. ‘‘Say, Joe, why is it that every bird who succeeds in scraping through the driver’s examination decides right away that he is the real thing as a driver and tries to navigate around in heavy traffic just like an old-timer? It would be a lot better for him and for the other fellows on the road if he would spend a lot of time on lonely roads practising gear shifting and maneuvering the car until he really knew how to do it right.”

rattled”’ attempt to back

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78 « pe! ¢ Sg] T ‘ lig ar ( ( block from automobile toe-in For the ay so that EADL pur ~ ver the burn- { al An O olte ling ne tight t! th re | } with t | hit b eh 1 be r ! IG out just when HT ul} Sa lu 1W ays seem to it is least con- ace them | sually ( dark road, late a heavy rainstorm. t worse the rim of the erally stuck ( ce exerted | W uflice to break it e we “pe rsuader”’ a f tire tape; white ( ( As shown in tne tape is wound é e headlight rim and of the roll serves as a ich to pi Short, sharp u more effective than a method of L ord motor a an ra ing the } to cut out some of the vibra tion. It kee} y acre ape liy 1] smai ( brace the Ford mot Fig. 2. nat some ( to the turned up 1 ir? n De er |] e grind) It real head is ] + na to WO! 1 the ( rl an ¢ I yme rting and N Fig ] r oO ar h tl ar, set one wheel a sight taken across the inside of of Turnbu POPULAR SCIENCE MONTHLY Fig. 1. obstinate headlight used to x and elim- kles Y Ln, | oe nt _————n } | i— - g How to alir 1 1ee] to sx P rr t Tape can used to that be Tim start is stuck an September, 1925 Handy Kinks to Aid the Car-Owner Seven Ways to Save and Expense in Auto Repairs the center line of the other rear tire, you can be sure that the front wheels have the correct amount of toe-in. Of course the test should be made on a level floor and the tires should be properly inflated. Remember also that this rule does not hold good with over-sized tire: nor on cars having a longer wheel bas: approximately 100 inches. aay en every little bump in the road is r¢ transmitted to the chassis of the ear. Roads that are full of small bumps, such as cobblestone streets, are negotiated mere easily if the springs are lept well oiled. An occasional splashing with old crank- case oil does the work, but it is better to have some means of con- stantly feeding oil in be- tween the leaves. Serviceable oil clips for than the spring leaves ir are ¢ Fig. 3. holding the cylinder This method of supporting and head will removing carbon and grinding valves n ri ig t Ss t] front tire near the axle strikes the ‘enter of the tread of the rear tire, as il- lustrated i inside edge of i Fig. 4. the Then look other front across the tire and if you find that the line of sight also strikes this purpose may be con- structed cheaply and easily of some sheet-metal strips, 1 by 7 inches, with three holes in each. Dent down the metal around the center hole, using a ball-peen hammer as shown in Fig. 5. Then when the metal is bent around the spring with a piece of lan p- wick under it, the center hole will form a small pocl et that projects upward and can he fille from an oilcan. The best way is to have eight clips on of each rl A little kerosene mixed with t old crankease oil will make the oil pene- trate between the and lubricate them properly. aid in all—one each side S] shackle. leaves "THE illustration in Fig. 6 shows how to make a very serviceable hose clamp from a piece of wire and a cotter- pin. The brass wire sold on spools for automobile use is suitable, and it is a good idea to use a good sized cotter-pin, so that the strain of tightening the wire will not pull it out of shape. After the wire is arranged as shown in the drawing, it is drawn tight around the turning the cotter-pin with a nail. An advantage of this method is that the clamp can be made cf any aesired size. hose by PS the most difficult part of grinding lies in making that none of the valve-grinding compound drops into the cylinders accidentally around the valve-stem guides. Part, at least, of the worry on this subject can be eliminated by the use of a cylinder QERHA sur } aown } cover constructed and used as shown in Heavy cardboard or wallboard will do for the material and holes can be cut at the points where the valves are located. or studs with winged used to hold the cover in place. Another advantage of using 4 cover over the cylinder openings is that no dust from the air can settle in them. Cylinder-head bolts nuts can be = 0Q re ( 1es aye tu VO rd ( re naa gabl tilators. tre rht September, 19; VY MANY attic spac needed de is presel nade aecessib! staircase ler if the r or a boy. ftentimes | by the us es, or by ct means ¢ mers harm of the h ires 1 and 2 possibilit Although ea certain ‘ases, so t steps in b ‘al house y such we ‘iling joist i gabled roo’ of econon ‘able to rn angles t« f the shor being pla is desirab] to be para any of led. wea cutt As t 10 in. fir ances ma than thes rm wicth. ss up thro

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September, 1925 & - POPULAR SCIENCE MONTHLY Home Worksho Arthur Wakeling, Editor & Fitting Up an Unfinished Attic How to Reclaim Waste Space in Your House—Setting Joists—the Flooring By Edwin M. Love N MANY homes there is sufficient attic space for the building of a needed den or bedroom. If no stair- vay is present, such a room may be made accessible by means of a disappear- ing staircase in the hall, or even by a ladder if the room is to be occupied by a man or a boy. Oftentimes light and ventilation may be had by the use of windows already in the gables, or by substituting windows for ventilators. If, however, there is no lirect means of getting light, one or two dormers harmonizing with the architec- ture of the house may be constructed. Figures 1 and 2 (upper drawing) illustrate these possibilities. Although each house is a problem unto tself, certain rules of construction cover cases, so that a careful following of the steps in building an attic room in a typical house will illustrate the principle f any such work. Ceiling joists usually extend crosswise ofa gabled roof, tying the walls. For rea- sons of economy, in this typical plan it is desirable to run the attic floor joists at tight angles to the ceiling joists, making ise of the shorter spans, but necessitating ‘being placed above the ceiling joists. : is desirable even when the floor joists are to be parallel to those of the ceiling, since any weakening of the timbers be- cause of cutting for electric wires is avoided. As the greatest span in 12 ft., 2 10 in. fir stock is used, but local demand heavier scant- All should be sized to a rdinances may ngs than these. niform wicth. Pass up through the hal! scuttle a num- q Fig. 1. ber of the planks and distribute them as in Fig. 5, page 110, to serve as a working stage. Drop a plumb bob from the ridge comb (a weight suspended from a cord is sufficiently accurate for this purpose) to determine the center of the room, and lay out the width, which in this case is 111% ft. For bearings for the floor joists, fit 2 by 4 in. blocks on the bearing plates, using two thicknesses, which should rise above the tops of the ceiling joists % in., giving clearance for the beams. Lay off distances of 16 in. from one side, making an X beside each mark to show on which side the joist isto bear. The space at the other side of the room is less than 16 in., but if no great load is to be carried, the dis- tance may be divided to save the extra joist shown in the photograph (Fig. 3). Remove the roof braces shown in Fig. 4. Select a straight joist and set, crown CEILING LINE OF ROOM IRST in a new series of articles contain- ing invaluable pointers on house woodwork for every homeworker A typical bungalow of the Califcrnia type with an unfinished attic that could be con- verted into an extra room by adding dormer and gable windows, as shown by the dotted lines of equal thickness to avoid errors due t9 curvature in the joist, as shown in Fig. 2: It is preferable to cut away the bearing edge of the high end, but if this brings the beam in contact with the ceiling loists below, shim up the low end with a strip of wood. Continued on page 110) This month’s Home Workshop Depart- ment will be found on pages 79 to 82 and 88 to 111, The Shipshape Home on page 86, and The Better Shop Methods De- partment on pages 84 and 112 to 120. edge up, at one side. Testfor _ {| doy | , 1, st levelness by means of a__ !NTERSECTION OF SIDE WALL WITH ROOF’ straight-edge and level. The SPIRIT LEVEL >y BOCK ls of the straight-edge eee eee ll ends o 1e straight-edge =STRAIGHT-EDGE sy, should be supported by blocks a Seager : FLOOR JOIST ] UO Fig. 2 (at right). Apia imieT)_—~ r House with added ahi ade PLASTER | atticroom and details . showing methods of : _ —_ cameiien setting and bracing f J floor joists, bridging icq and laying the floor ee Pern JOIST ENDS TO LINE ie Fig. 3 (at left). Mod- el showing frame- work of flooring laid TRA to center of room prior to nailing the upper ends of the herring-bone bridging . ON PLATE ™ Lotti A ISTHICKER THAN B 2 a . PLATE CEILING JOIST 4 I] {J Ley | ~ STAGGERED’ a | G HERRING-BONE BRIDGING boi BEVEL ENDS

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80 POPULAR SCIENCE MONTHLY September, 1925 Carving with Your Pocket-Knife Simple Checker-Board Ornamentation for Small Boxes OUR jack-knife, Q-- a hammer, and a few nails are all you need to make these handy little their deco checker-bo boxe S with rative ard pattern. The same pattern can be applied to a great many articles — picture ales ‘ : : Vanity boxes, Smok- ing cabinets, book ends, stationery racks, and all sorts of woodwork. For any one who has not discovered the fascination of jack- knife i and wishes to learn to whittle, this ty of carving will commend itself because ae its simplicity. Butternut wood was used for the handy little toolbox illustrated in the right-hand column, because it not split easily and the grain is generally straight. It is easy to work with and, when finished, its of the harder woods. clear, fine-grained wood, does color looks like However, some any such as white ated or basswood, is suit- able. White pin was used for the smaller vanity “ema shown at the top of the page Make the box for your own require- ments. W pencil an ruler or try- square, draw squares of about 16 in., leaving a border around the outer edge. A touch of beauty and artistic workman-

By Herbert I. Childs Childs, of Worcester, Mass., an authority on pocket-knives and the almost lost art of whittling, and a vanity box he Herbert I. carved to illustrate the very simple and effec- chec tive ker-board pattern he describes in the accompanying article. Other articles on useful pocket-knife work are to follow Your initials may be cut in or raised. If to be raised, cut out the surface around them as far as the border to adepth of )in. Sandpaper the flat surfaces of the box and finish with shellac, wax, varnish. The wood can be stained, if you wish, before the finish is applied. For the of your knife or sake as well your work, do not use a dull knife. As soon as it does not cut clean, sharpen it. Use a fine grain oilstone with a flat surface, upon which a few drops of clean oil have been placed. If sharpened on a dry stone, the edge is likeiy to be rough. For general use, the edge of the blade should rest on the stone at an angle cf about 20 degrees. Draw it from heel to point across the stone from right to left; turn the blade over and draw it across rom left to right. The stroke is always cutti and not with it, ropping the blade The beginning of a stroke from against the ng edge as is the leather. when st on case left to ht is illustrated above. Ke » the sharpening process until the edge is keer Chis may not come to ou at first, but after you have tried it a few til you W l e the vantage of taking tl care in setting the edge. If COSC LL roo 7 nnn | /

ape ebaka | } ae | ek s@aia Es c E v Poor |) — Stn 1 | skh ebswa jJ j ro | rm rj Bal. ae 7 J a at ae r nn rr rH nn 11? nore ron | § ka Suggestion for laying out tne front of a box with initials in a central rectangle stone, strength in ordinary use. the blade is too flat in relation to the too thin It the edge will be times desirable, however, for a thin edge when very light, thin cuttin is to be done. blade is held at too great an angle, not cut properly, as the strike the work knife is held whittling. in the natural manner x On the other hand, : the is some- to sharpen ai, t will deri will Willi before the edge when the for To insure good results, you should have It should have a large blade for rough or a knife that fits your hand fairly well. straight work for the finer details. A small toolbox of butternut wood decorated with checker-board chip carving and careful in your selection, get good results from a factured. knife The quality of steel in the blades, tempered to a hard, high, and temper. The blades should be ground with truly tapered sides. for you poorly initials knives on the market are of a low grad: ’ first essential is a knife with a fi: accuratel) toug! carefully Man\ and one or two small blades You cannot be too

cannot manu- of and steel, poorly tempered and ground, a have no value for whittling and carving work. Avoid these and select one of the igh grade American-made pocket-kn which can be A A quire rOOD knife vourht and only edge will be an occasional touching the on an oilstone. knife is permitted to get into very shape, it Wi the gene ral regular jac k-} n} ife whittling, it rving to ha suitable is useful for spe are should rarely require “ches ile the usual spear-shaped blades made as keen as a razor. sharp whe for a long time should re- 1V¢ Unless a pocket up ( ‘ a ca ve a narrow, straight-ed mall blade with a long point, the ba curving down to ss stra — edge. ' O “Wharn lif Te’ , ““sheey ) me Sloyd or mode it do not |} ides tha } is called a

y a tn edge until about Way across the | Die With its thi heavy back, this eho is sic as a sal shaped or full-swaged blade. A point blade is one chat is similar Turkish sword or scimitar, the back ne eT- being hollow ground or concaved befor reaching the point.

September Hc - WO! elect H heard! y practically anything « be repaire: When break in 1 either in 1 itself. It another <¢ otherwise especially Take the piece and nected tig you have | cord, test described MONTHLY the Cords ances,”’ Ju When y is within mount. it. the parts of the he: the initia! Fig. 2, the In some block and Next, screws, W

Fig 1. age iron the hanc however that are ment c: = Fig. 4 (; the bre: other sic ends ab so that

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September, 1925 POPULAR SCIENCE MONTHLY 81 How to Repair an Electric Iron W hen the Heating Element Burns Out, It Can Be Mended by Joining the Ends of the Broken Resistance Wire “ WONDER what’s wrong with the electric iron? It won’t heat up.” How often this complaint is heard! Yet a modern electric iron is practically indestructible and hardly anything can go wrong with it that cannot be repaired quite easily by any handy man. When an iron fails to heat, the break in the electric circuit may be either in the cord or within the iron itself. It is well to test the iron with another cord, if one is available; otherwise examine the cord with care, especially near the attachment piece. Take the cover off the attachment piece and see if the wires are con- nected tightly with the terminals. If you have any further suspicion of the cord, test it by the means previously described in POPULAR SCIENCE MONTHLY (‘‘Howto Test and Repair the Cords of Household Electric Appli- ances,” July, 1925, page 92). When you are certain that the difficulty is within the iron, the first step is to dis- mount it. This necessitates removing the parts that interfere with the exposure of the heating element. Figure 1 shows the initial step in removing the handle; Fig. 2, the removal of the terminal block. In some types of irons the terminal block and handle need not be removed. Next, take out the main assembly screws, which hold the top of the iron in By Leroy S. Foltz Professor of Electrical Engineering, Michigan Agricultural College position. This will allow the top to be lifted off and the element to be exposed. An examination of the heating element will reveal the location of the trouble. In this case the element has burned ‘‘open,”’ as shown in Fig. 3. It is necessary to connect these two ends in such a way that the joint will not melt when the current is applied. To accomplish this, unwind the wire ribbon each way to the other side of the element (Fig. 4). Clean about 2 in. of each end thoroughly with a piece of emery or fine sandpaper. Now form one end into a flattened coil of two or three turns and insert the other end into it. Reduce the size of the turns and pull up the slack in the wire. With the pliers, flatten the coil firmly down on the inserted end of the wire, as in Fig. 5. Be sure to have the coil flat so that projec- tions will not wear holes through the adjacent mica. In order to prevent the joint from interfering with the wires on each side, it is well to insert a small sheet of mica under it, as in Fig. 6. ij The element now may be tested by applying voltage to the terminals and noting how the joint performs. If it becomes excessively hot, it should be adjusted to give a larger and more uniform contact between the wires. When the iron is reassembled, the pressure put upon the element will im- prove this contact. Besure to havea little extra mica both above and below the joint—between the element and the top and bottom of the iron. In case the resistance wire has become so badly damaged that it cannot be re- paired in this way, it will be best to discard it entirely and to purchase a new heating element. These come fastened between sheets of mica, ready for insertion. Steps in Fixing an [ron These illustrations show graphically the steps required in fixing an electric iron. This is one of the most fre quent, as well as one of the simplest, repairs the home worker is called upon to make Fig 1. To disassemble the aver- age iron, it is necessary to remove the handle. This is not required, however, with some types of irons r that are so designed that the ele- ment can be uncovered quickly Fig. 4 (above). The resistance ribbon at the break or ‘‘open’’ is unwound to the other side of the form in order to give free ends about 2 in. long, or long enough so that they can be twisted together mpecenpcre pea _—— ATES E I Fig. 3. A typical heating element, showing a burned-out or ‘ open’’ spot ————— |) Vig 2 handle, the next step is to unscrew and detach the terminal block. Then remove the main assembly Having removed the screws, which allows the top to be lifted off and the mi removed. Screwdriver and pliers are the only _ tools 1 insulation required Whenever taking apart any elec trical appliance make a careful mental note of the exact position 1 of cach pie before moving it Fig. 5 (above When connected, the ends of the wire are flattened down with pliers Fig. 6 (at left A small piece of mica is slipped beneath the completed joint

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Drill Press POPULAR SCIENCE MONTHLY of the cast-iron tee, J. The pipe G is not turned in the lathe, but simply has any unusually rough spots knocked off with the file. The 3-in. cast-iron tee J has a 2-in. outlet for F’. It is chucked and bored so that it is a sliding fit on G. The two 3¢-in. screws Z are used to lock the table at the desired height. The block N is a piece of l-in. steel large enough to receive the ball bearing selected for this point. It By Ray F. Kuns Principal, Automotive Trades School, Cincinnati, Ohio. RIGINALLY designed for a home workshop, the drill press illus- trated looked so well when com- »leted that it was placed in a shop, where t ; giving complete satisfaction in constant service. One of the most interesting things about this drill press is the fact that incor- porated in it are seven ball bearings, all salvaged from automobiles. In fact, a great part of the material was taken from With hundreds of thou- sands of automobiles being scrapped each dismantled cars year, there is an ever increasing field for the use of their parts in building up special garage, machine-shop, or home- workshop equipment No attempt has been made to give detailed dimensions. The suecess of a } piece of work of this kind depends largely on the ingenuity of the mechanic in ! | e of the parts at ha a Che main part of the macl rm be per- formed 01 engine ltatne The } BD eavy brake drum with four pieces of 3-in. angle riveted to it et \ hub flat ge, which has been bored out to receive the pipe C, is bolted or riveted to the brake drum. The frame js built up by welding pipe together. G is a piece of 3-in. gas pipe. The curved arm F is a piece of 2-in. exhaust pipe, the curve being the original one. FE also is a piece of exhaust pipe, about 1 in. The brace E' is not added until later. The table support must be planned before the frame is assembled on the base, unless a split support is devised in place is welded to the post, after being bored on the lathe to take the ball bearing. N' is another piece of 1- in. stock and is bored to carry the bearing support- ing the other end of the shaft that carries the lower cone P and the tight and loose pulleys M and M’. N' is welded on a_ bracket built up to the height of the brake-drum base. BB is a length of 14 by 2 in. flat machinery steel, and the bar BP is “xs by 6 in. flat steel. The lower shaft O is made up from an axle shaft and has the ends machined to fit the bearings; the other parts are machined to care for the pulleys. Both cones are the same size and are built up from 1!s-in. oak or other hard wood. The particular machine illustrated is provided with both a tight and loose pulley. This allows for connection with a line shaft or individual motor, as shown in the photograph. The pulleys M and M' are 12 in. in diameter. They may be made from old brake drums. The table C was made from an engine flywheel. It was faced off in the lathe and the edge turned down to 1 !s in. thickness. The end of the crankshaft with the flange Y, which fits the flywheel, forms the table mount- ing. H IS a 2-in. cast-iron tee. If \ 1 not is large enough to permit boring the tee, it may be bushed by screwing short or close nipples into each of the ends and then the tee is chucked and bored to receive NX as a sliding fit. The length of F' will depend on the swing of the drill. It should bring the center of the table under the center of the drill bit. |The screw in the 2-in. tee locks the table in any desired position. The building of the drill-press head is, of course, the most diffi- cult part. F° carries two ball bearings, one in either end. These in turn carry the shaft A. September, 1925 Built from Scrap Has Seven Ball Bearings Salvaged from Junked Automobiles Another ball bearing in G® carries the driven gear W. These three bearings must be in line. The plate D, which is a piece of steel plate 3¢ by 6 by 19 in., is welded to the pipe frame. F* may be a piece of 2-in. pipe or tubing. A shoulder is provided when boring to allow the ball bearings to strike it when they are pressed in. The spindle A is machined to assemble from the bottom of F’ so that it has a shoulder to take the thrust. Ball bear- ings are usually made tc take a thrust in one direction only and this point should be considered in selecting and mounting these bearings. HE rack J is screwed to the part F*. The shaft S, which carries the pinion that actuates the rack, is carried by two blocks of steel, LL. One end of this shaft carries a plain lever bar marked R and the other end carries a ratchet gear. This gear is engaged and operated by the lever T, also salvaged from a car. The lever is balanced by the weight U. G' is a piece of tubing with a bore to accommodate F” in a sliding fit and ma- chined to allow the rack to project at the rear. It is supported by two strips of angle iron. These strips, K, are welded to the tube G' and house the rack and rack pinion. They in turn support the blocks L and. when mounted to the plate D, support the entire lower part of the drill-press head. The gears are salvaged from a car. V is one of the little gears from the differen- tial. It is a spider gear, and drives a side gear W. The ratio is about 2 to 1, which is usual practice. W will be found to have a collar-like flange on it, and this (Continued on page 108) sae | } | | } fo) » — = z Front and side views of assembled drill press made mainly of material reclaimed from the automobile junk yard Sept Lat & « | fet terres ewes ss

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September, 1925 POPULAR SCIENCE MONTHLY $3 How to Finish Furniture —New and Old OHNSON’S (Penetrating) If you have a hobby for making chests, | Johnson’s Wood Dye is for the artistic cabinets, furniture, porch swings, radio coloring of all wood. It is very easy to boxes, etc., you will find our book on apply—dries in four hours and will not Wood Finishing invaluable. For, nat- rub off or smudge—penetrates deeply, urally, you want to give your handi- __— bringing out the beauty of the grain. work a beautiful finish. Made in 17 beautiful shades, among the ; . ; most popular of which are: Our Book gives complete instructions id for finishing new and refinishing ol 123—Dark Oak 131—Wainut wood—soft orhard. Ittellshowtostain 129—Dark Mahogany = 126—Light Oak a 127—Brown Mahogany 124—Golden Oak wood artistically—how to remove old paint and varnish—how to secure a Order Johnson’s Wood Dye from your beautiful enamei finish. dealer by name and number. presiserese***FREE—25¢ BOOK ON WOOD FINISHING-----~---=~ Ask for a FREE copy of the Johnson Book at stores displaying z the mm shown at right. These stores carry Johnson’s 4 Artistic Wood Finishes and will be glad to show you wood panel Is— a answer questions on hh yw to properly finish he PROPER \f wood. If no stere in your locality can supply the Johnson Book—mail this coupon for a copy Free and Postpaid. TREATMTRS ) YOUR DEALER'S rAME woodwork a & Your Name ; : FURNITURE or ] Your Address ARTISTIC City and State selaii Agar i Maitto: S, C. JOHNSON & SON, Dept. PS9, RACINE, W/S. INIS i ““The Wood Finishing dathertties* (Canadian Factory: Brantford) J ‘S) This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS See page 19.

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84 POPULAR SCIENCE MONTHLY September, 1925 ene oy Better Shop Method How Expert Mechanics Save Sime and Labor a raat (Chasing a Difficult Vhread Old Bill Repairs a Pump LD BILL put down the trade paper he was reading. He rarely found time to read anything for more than a few minutes before some one opened the door that separated his office from the noise of the shop. “This pump | am working on begat the machinist who had entered. Old Bill smiled and nodded. He knew the job. It was a duplex steam pump that had been sent to the shop for a gen- eral repair “One of the water valve seats,’ thi nachi { nt o “has come out of the casti ind the threads » all worn off.”’ Old Bill f 1 th lechaunie out of Ul office, fe h had | ymised to hav that pump bac S on the following It mid { 8) 1 here wa if ( to I ao I"} yu W: \ ry radial drill ess t | t 1 do gi tools fo the seats were something ike an end n ex t that the teeth went entirely across the face. There was a pilot to go into the hole in the middle of the valve seat, and a shank to fit the drill-press spindle “T had them all done but this one,” the machinist said, “and about the time I got the cutter in contact with it, I noticed that the seat turned. I stopped, and it came out with my fingers. The threads are gone from the casting as well.” Old Bill saw that the brass seat had only the semblance of threads, and the casting had been attacked so much by rust and by the slight movement of the seat that it had no threads at all. And the pump must be delivered the next day! Old Bill knew that he could build up the brass valve seat with a welding rod and re- thread it again without much trouble, but to getsome threads into the pump casting was another question. The cylin- der and the frame were one casting, so chasing a thread in a lathe was out of the question. He thought of taps. But when he measured the valve seat, he knew that he had no tap that was 41% in. in di- ameter. “How about reaming the hole and driving the valve seat in?’”’ the machinist suggested. “‘Some of them are made that way.”’ “We might make a tap,’ ventured another mechanic, who had stopped to look. “T promised to have this pump done in the morning, and we should not be able to make a tap in that time, even if we could find a piece of steel already an- nealed,’’ Old Bill said. “I believe the best way will be to chase another thread and screw the valve seat back in.”’ One man opened his mouth; the other eyes a trifle. Old Bill handed the valve seat to the machinist on the job and said, “Get the welder to build up the thread right away.” The mechanic reluctantly left on his mission, for he was anxious to hear the idea Old Bill had in mind. , +L? closed Nis y 7" WILL chase the thread here on this drill press,’’ Old Bill told the machinist who remained. He smiled at the incredulous look of the machinist and continued, “‘Don’t scowls»! All you have to do is to make a boring-bar witha thread, and a guide with a threaded hole that you can bolt across the top opening.” Old Bill looked around the base of the drill press. There had accumulated a mass of bolts and clamps that were used to set up work. He selected a bar about 1 by 3 in. and something like 2 ft. long. “This will make the guide,’”’ he said as and Renews a Gear By James Ellis, Machine-Shop Superintendent he laid the piece over the top of the chamber. “Now get a threaded hole about here.’””’ He made a mark on the bar just over the worn hole. “I think that we had a 1'%-inch tap with eight threads to the inch made for some special job. If you can find that, it will be fine. Then make a boring-bar to fit the threaded hole. You can turn a straight shank on it and hold it in the drill chuck. Hold the tool with a setscrew.”’ The machinist grasped most of the idea. Old Bill went on: “I forgot to say that you should hold the guide bar on the chamber with some of the studs that hold on the cover. They are right where you want them.”’ This was something new to the ma- chinist, but he set to work to get the parts ready. The other machinist was back by this time, and after the idea had been explained to him, he started to make the boring-bar. With two men at it, the tools were soon well under way. Old Bill, resisting the lure of the article he had been reading, made the rounds of the shop and came to a gear about 4 ft. (Continued on page 115) ANY time-saving shop ideas are contained in the continuation of the Better Shop Methods Department, which you will find on pages 112 to 120, Radial drill set up for threading, and facing tool with teeth neither radial nor evenly spaced September, 15 Comp: Divide you 1 Starre partici You'll fine q nicely strong the rig work, faithfu Calipe: ing an The ai

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September, 1925 POPULAR SCIENCE MONTHLY alipers and Dividers Compare Starrett Calipers and Dividers with other makes and you will begin to see why Starrett Tools are preferred by particular mechanics everywhere. You'll find them made from a fine quality steel, tough and nicely tempered. The legs are strong, the springs have just the right stiffness for rapid, easy work, yet holding a given size faithfully. Set a pair of Starrett Calipers or Dividers in the morn- ing and they stay set all day. The adjustment is particularly sensitive. Once you are accus- tomed to the ‘feel’ of your Starrett you can work to sur- prisingly close limits. points are nicely shaped—di- vider points unusually accurate. Threads on nut are absolutely true. Note the lightness and balance, the nice finish, the obviously superior workmanship in every part of a Starrett Caliper or Divider. None better—at any price! THE L. S. STARRETT CO. W orld’s Greatest Toolmakers Manufacturers of Hacksaws Unexcelled Steel Tapes—Standard for Accuracy ATHOL, MASS. IS} This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS See page 19. Caliper / 85 Why Do Gocd Hardware Stores Everywhere Sell Starrett Tools n this group are tarrett Firm J ct te 1 pers No. 243 (with off- t I ez an l A Ijust wie Round Poinf), Starrett k-Joine Transfer ralipers No. 36 (with mproved Transfer De m) and Fay Spring Dividers No Quick Adjusting, Automatic Closing Spring Nut). Write for Catalog No. 23 "V4 for complete descrip- tion of Starrete Cali- 77 (with pers, Dividers and other Fine Precision Tools.

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86 POPULAR SCIENCE MONTHLY September, 1925

How to repair shingle, composition, slate, and metal roofs—A simple “creeper —Painting roofs

\ ANY a home- 4 owner who takes pride in keep- ing his house ship- shape is at a com- ylete loss when it comes to roofing repairs. This is natural, because the roof is usually an inaccessible and awkward place to Yet, a little care given to your roof, whether it is shingle, composition, siate, tile, | How to Repair | Leaky Roofs

work. é or metal, will repay you greatly. By looking after a roof from year to year, its life can be preserved surprisingly and, of course, the annoyance and often costly damage caused by leaks can be avoided. There is nothing especially difficult in repairing a roof, provided you know how to go about it. If you have a shingled roof and it leaks, go into the attic and wherever daylight shows through, drive small s>linters of wood up into the cracks. These will indicate the cracks when you are working on the outside. If no light is visible, note the approximate location of the tell-tale damp spots. Put your ladder up outside and set your ‘“‘creeper”’ cr roof scaffold If you have no ere eper, all means make one, as it will In aid in place. by be useful for years to come. Z of a fi atly in reaching the Almost any board that is as long as the roof from the eaves to the cast roof fire it may gre flames. will si ridge rve as a_ creeper. Nail cleats to it about 1 ft. apart. Che upper end should have a hook > this car pe I as show purchased or forged from an iron bar. Bolt it securely to the creeper After | lacing the hook over the lways test by pulling down sharply on the creeper before trusting your weight on 1t. 1ldge, a d shingles are out, nailing them in ag new shingles into any places where the ol i] place Where the shingles merely are split lide pieces of tin cr galvanized l f them f enough so that the upper part is under the top course of shing N dow} ll loose shingles and repla N badly damaged ones. A t of good shingle paint will aid i ving the \ very economical més ( ny ] Img 5 gals. ( gr] tain, 3. gals ( at n dri ! ( t TI S] ( ut h oportions ( t S { By adding of t] ( ed, nost Vv co t to e obtained 1} should not recomme this paint for led e walls, as it would remain tacky for some time lf your roof is of the composition shingle type, mark the leaks as for wood shingles, or note their approximate positions and proceed in the same way, except that a small dab of roofing cement the color of the shingles should be applied over each nail. If you cannot obtain roofing cement of the right shade, mix asbestos fiber, which can had from almost any plumber or ‘teamfitter, with a paint of the proper color until a putty-like paste results. This filling for small holes and cracks will last for years and will remain flexible. If the shingles have dried out or the surface has gone, there are a number of colored paints with an asphalt base that may be used to renew the life of the roof. I'nder no circumstances use paints with be

Using a ‘creeper’’ in repairing a shingled roof. A tool fer removing broken slates a linseed-oil base on a paper roof as such paint will destroy its weather-resistance. If your roof is slate or tile, an entirely different method of repair is necessary. Go over the surface of the roof carefully and remove all slates that are cracked crosswise of the slate. Use the tool illustrated, which any blacksmith will make for a dollar or two, or which can be purchased from a hardware dealer. It is called a “ripper.” the slate i] the I mly s working end under the and move it back and ail holding the slate in ated in one of the hook- Then by jerking be If it end hvietertadel ETE DrOnReC forth unt place is fi like notches. irply down is too of the the nail stubbornly car cut the handle may be ham In the crack slate that has bee -opper or s upper mered. or joint directly under the n removed, nail r soft brass about 14 and 4 in. long in such a lower end will project 1 lower line of the slate is to go. a pl ce in. wide way that the in. below the course where the new Then slide the new slate up even with the other slates in this course and bend the copper clip up in ho fashion. nently in place. Ii a slate must be cut, lay it along stone step or a square piece of iron ar This will hold the slate perma ‘ cut it with an old file or hatchet by using short, sharp blows. Holes can be punch« with a sharp nail or punch. amount of slate must be cut, it is best t If any larg employ an experienced slater or to pur- chase a set of slater’s tools, which cons of a hammer, ripper, and stake. ‘T latter is a T-shaped, flat steel anvil. If your roof is tile, by all means get é —< i aoe experienced roofer. Tile rocfs are dit + cult to repair because the tile must be laid to allow for expansion. Metal roofs are easiest for the amateur to repai Solder or cement all small holes « cracks and then paint them with paint. If the roof is loose, fast: and solder cement surface. or over metal roof, scrape the metal unt and rosin for tin roofing). Sold heavily with a clean, hot iron. F YOU wish to make your ow consistency. Brush this with much care as if you were painting tl paint for galvanized iron, use thi best red oxide paste and thin with pure boiled linseed oil to the prope good grade of iron oxide or red lead it down with large headed screws thei dry and clean and use a good flux (muriatie acid for galvanized roofing perhaps” the To do a good job of soldering a house, and your roof will last for years When working on your roof, alway fasten down all metalwork around tl} chimneys or dormers and be sure whi painting valleys on crowd the paint up under the edges of t} shingles, as it is here that 90 per ce: of the leaks in the valleys occur. If copper valleys have been used, : agreeable color can be obtained by pair ing the metal with a solution of vineg and salt water. 7) a shingle roof t bright green, which contrasts beautifully the duller slate or shingled si C. W. HuBERTZ, Corry, Pa. with faces.

PROFESSIONA furniture finishe generally a agreed that lem« oil polish is the most satisfactory for res lar use. harm the finest furniture is 1 Polishing Furniture

oil and 2 heaping teaspoons whit! mixed. Add 1 qt. water and shake we By adding a generous quantity of rotte! stone powder to this polish, it becom: an excellent abrasive for improving ol duster-scratched pianos. This turns the copper a Another good polish that cannot pt. neutral f

et tc nnn a

September, |!

b a h t O1 cc st nN Si

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September, 1925 “IT had a hot air furnace in our 7-room house before I got the Bulldog and our house was always cold. With the Bulldog it only takes half as much coal and we had weather below zero, and the house was nice and warm in the morning when we got up. We never Furnace Heats Seven Rooms Where Stove Heated One “Your letter received asking about the Bulldog furnace. We have had ours in about six weeksand so far it does all Babson Bros. claim for it. We have seven rooms, four on the first floor and three on the second and it heats them fine. We find it takes a little more coal to heat the whole house than it did to heat one room witha stove using chestnut coal.”—J.B.Smith, 19 Elm St.,Somerville,N J Heats Home for 25c a Week ! “I can run my Bulldog furnace for fourteen days in normal weather conditions on the actual cost of fifty cents.”’ So writes F. R. Redetzke, of Cleveland, North Dakota, and Comes Completely Erected. Install It Yourself The Bulldog is sent to you for free inspection. Then, if satisfied, you make only small monthly payments at our remarkabl y low price. Write today! Don’t miss this chance to cut down your fuel bills! Jnstall a Bulldog Furnace. It comes to you completely erected — goes through any door— fits any height of base- ment — and you install it yourself in less than two hours! In fact, H. B. Keater, of Libertyville, N. Y., says he installed his Send for Free amazingly low price! Send for Free Book TODAY! BABSON BROS. i io and California Avenue, Chicago, Ill, EERIE. 8 OTREL Ta 00k Learn how to have all the heat you want—where you want it— and save money! Remember the Bulldog is different—and better! Complete combustion of gases save 25% of your fuel bill. sive Gable-Top Radiator receives all the direct rays of the fire. Exclusive oblong fire-pot is not only ideal for coal, but enables you to keep a wood fire over night. Remember—the Bulldog is sent for free imspectton— then small monthly payments at an POPULAR SCIENCE MONTHLY have tne draft on more than half an hour at a time, and it has the place red hot. It is easy to regulate and keeps the fire all day in mild weather. JESS T. CONRAD, 1121 W. Arch St., Shamokin, Pa. 2\, Tons Heats 5 Rooms ‘There is no heater to compare with the Bulldog. I burned 2% tons of coal last winter and heated five rooms and a bath.’’— Walter Geary, Gloucester, Mass. That’s what the Bulldog does with coal! Now read, in the letter of Mr. Redetzke, what it does with about the lowest grade of fuel you can think of! he adds: “Hard to believe, is it? That’s what some of my neighbors thought until I showed them! We have an un- limited amount of grain screenings which I use for fuel.” Bulldog in 28 minutes! Don’t put up with the old fashioned stove heat or some outworn furnace — when you can so easily get the greatest advance in scientific heating at an astonish- ingly low price. The Bulldog burns almost amy kind of fuel. from hard coal to cheap screenings. Keeps a wood fire over night. We have factory connections in both east and west and ship from the nearest point. Babson Bros., Dept. 13-66 19th St. and California Ave., Chicago, Ill. Without obligating me in any way, please send me your free catalog and special offer on the Bulldog Pipeless Furnace. Exclu- © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 19.

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LeeUnion-Alls A Necessary “Tool” For Your Workshop bene the man or boy who has a home { thy JL’ workshop, Lee Union-Alls are a handy “tool” to have about. All that is necessary when you want to get busy is to slip into them and start your work. They cover the body from head to foot and can be worn over other clothing. They save clothes, also. And they save time where the hours for such work are limited. Wear Lee Union-Alls, the original one- piece work suit, worn by thousands of mechanics, shopmen, garage workers and industrial workers. Lee Union-Alls are quality-built—close-woven cotton fab- ric, riveted rustproof buttons,reinforced strain points——fully guaranteed to give satisfaction. They give solid comfort, long wear, and are neat in appearance. Accept no substitute—look for Leeonthe buttons. Thousands of live dealers sell Lee Union-Alls. Ask your dealer today! THE H. D. LEE MERCANTILE Co. Kansas City, Mo. South Bend, Ind San Francisco, Cal =, | iI \ | | | | F | Ar) (eA, P Lb f | | | | 1 ee ——* | | worker, or you can | showing the POPULAR SCIENCE MONTHLY September, 1925 We Ome WorkS)ra@D Building a Tea Wagon Is a Fine Project for Leisure Hours One of Many Things You Can Construct with the Aid of Home Workshop Blueprints EST results in building furniture, radio sets, workshop equipment, and the like for your home will come from following well worked out and fully detailed plans such as those con- tained in POPULAR SCIENCE MONTHLY’S series of blueprints. If, for example, you wish to make a tea wagon such as the one illustrated, you can work without any definite plans, piecing the parts together serve as the basis for the main construc- tion. It gives him the necessary starting point for his work. If you have not yet taken advantage of this service, why not try one or more of the blueprints? It may aid you in making a selection if you know that the most popular blueprints have proved to be the tea wagon (No. 13), the sewing table (No. 1), the smoking cabinet (No. 2), the kitcher as you go along and trusting to luck that the assembly will be good looking when finished, or you can make a working drawing of your own, which is a time-con- suming and rather difficult under- taking for the aver- age amateur wood- obtain for 25 cents a blueprint with the cabinet (No. 5), th workbench (No. 15 and the cedar chest (No. 17). Unless you hav a good bench and ample storage spac for your tools, it will pay you t start by making the cabinet bench Not only does it pro- vide a working top of generous size and the most rigid con- complete drawings anda bill of materials exact size of each part. Merely to state these alternatives is sufficient to indicate which is the easiest and the one most certain to produce satisfactory results. The truth is that the more experienced a mechanic is, the more certain is he to use a drawing to work from, whenever possible. Even if he wishes to-change the size or shape or modify any of the details, he still wants to have a drawing that will A solid walnrt tea wagon made for $20 by H. Caldwell from Home Workshop Blueprint No. 13 struction. but it contains several convenient drawers and compartments for tools and materials. Among the other blueprints mentioned there is little to choose, except that the sewing table is the simplest and_ the smoking cabinet offers the most oppor- tunity for elaboration in the way of inlaying, carving, or painting. In ordering any of these, please use the coupon below. SCRRCKE SCHR EER SESSSTS SECS R RETO K SERRE CSRS SSH RH TRESS CERES RST ESRESERECS SECTS RE RSET CHS T ETE T HERE CRE SERS ORES ERE R EERE EERE HESE EERE EeeeEnEE OES ANY one of the blueprints listed Zz below can be obtained from POPULAR SCIENCE MONTHLY for 25 cents. The Editor will be glad to answer any specific questions rela- tive to tools, material, or equipment. Blueprint Service Dept. Popular Science Monthly 250 Fourth Avenue, New York GENTLEMEN: Send me the blueprint, or blue- prints, I have underlined below, for Waich fT ANClOke: 25. ..440.23 55 cents: \ Ti Publis] Price 1. Sewing Table Feb., ’22 25c | 2. Smoking Cabinet Mar., ’22 25¢ 3. End Table Apr., ’22 25c 5. Kitchen Cabinet May, ’22 25c 8. Shaving Cabinet June, ’22 25c 9. Arbor, Gate and Seats July, °22 25c 10. Porch Swing Aug 22 25c 11. Bench and Tilt Table Sept., ’22 25c 12. Electric Washer Oct. 22 25c¢ 13. Tea Wagon Nov., ’22 25c 14. Christmas Toys Dec:., °22 25¢ 15. Workshop Bench Jan., °23 25¢ 16. Inlaid Radio Cabinet Feb., ’23 25¢ 17. Cedar Chest Mar., ’23 25c PTTTTTT TIE Complete List of Blueprints No. Title Published Price . 18. Phone Table and Stool Mar., ’23 25¢ : 19. Grandfather’s Clock Apr., ’23 25« “4 20. Flat-Top Desk Apr., ’23 25c |& 21. Colonial Desk Apr., ’23 25¢ : 22. Cabinet and Desk Apr., ’23 25¢ . 23. Pergola Garage May, ’23 25c |: 24. Gateleg Table June, ’23 25¢ . 25. Canoe Sailing Outfit July, ’23 25¢ : 26. Baby’s Crib and Pen Sept., ’23 25¢ : 27. Kitchen-Cabinet Table Oct., ’23 25¢ : 28. Pullman Play Table Nov., ’23 z9c 12 29. Toy Tea Cart, etc. Dec:, ‘23 25c |: 30. Tool Cabinet, etc. Jan., ’24 2c i: 31. Sewing Cabinets Feb., ’24 25¢ i= 32. Chinese Game Table Mar., ’24 25¢ : 33. Dining Alcove Apr., ’24 25. ts 34. Garden Trellises May, ’24 p feos : 35. Simple Radio Cabinet Oct., °24 25¢ : 36. Rush-Bottom Chair Nov., ’24 2oc: is 37. Simplified Bookcase Dec., ’24 25c |5 38. Sheraton Table tan., -*25 25c 39. Salem Chest Feb., °25 25c |: 40. Desk in Sheraton Style Mar., ’25 25¢ js 4 One-Tube Radio Set Mey, ’25 25c “ 42. Three-Stage Amplifier June, ’25 25c |: 43. Four-Tube Receiver July, ’25 25¢ |: N Se eee ee a Pe ee : (Please print) . Ce ee a ee eae TA ee Ie a eee ee are ae ee ee 2 GUITARS 11) ST OM Ee ey : IS) This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 19. Septem on a Gulf He color will Tycos Whet other the Si ing T If you Temp that v prom Tycos | | mw

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eeeeeees Eeptember, 1925 Making Jelly for a Million Breakfast Tables yf Perec jellies and jams are made in huge copper kettles holding hundreds of pounds of bubbling, boiling fruit juices you will find Jcos Temperature Instruments being used to insure the uniform results essential to manufacturing food products on a large scale. The day is past when manufacturers dare to trust to rule of thumb methods to determine when the seething mass in the copper kettles have reached the right temperature. Science, in the form of Jycos Instruments for Indi- cating, Recording and Controlling Temperatures is used by the preservers to make it possible for them to put exact/y the same quality jellies and jams on a million breakfast tables from the Atlantic to the Pacific; from the Gulf to our northern boundries. Home-made jellies and jams can be made clear and sparkling, of good color and firm enough to retain the shape of the mold if the housewife will take a leaf from the manufacturers note book of experience and use a Fcos Thermometer, especially designed for home jelly making. MANUFACTURERS Whether making steel or soup, paints or rubber goods, bread or perfumery, or any other products that go through heat treating processes in their manufacture, you need the Sixth Sense of Industry, Heos Instruments for Indicating, Recording and Controll- ing Temperatures in your plant. If your manufacturing problems require the indicating, recording or controlling of Temperature, there is a type and style of instrument in the Jyeos Line of 8000 varieties that will help you. Informative literature on any type of instrument will be sent you promptly on request, or our engineer will consult with you on the application of Jycos to your particular manufacturing problem. faylor Instrument Companies Main Office and Factory ROCHESTER, N. Y. . : U.S.A. Canadian Plant: Zyeos BUILDING, TORONTO POPULAR SCIENCE MONTHLY Tycos Office Thermometers An aid in promoting human efficiency. Tycos Bath Thermometers To enable you to get the most good from your bath. Taylor Home Set Bake Oven Thermom- eter, Candy Thermom- eter, Sugar Meter. The secret of accurate re- sults in cooking. Tycos Wall Thermometers To help you maintain a temperature in your house conducive to good health. 89 Taylor Quality Compasses To show you the right way in unfamiliar country. Tycos Fever Thermometers A necessity in every home. Tyeos Stormoguide Forecasts the weather twenty-four hours ahead with depend- able accuracy. Tycos Hygrometer To enable you to keep the humidity of the atmosphere in your home correct at all times. Your dealer will show them to you. Ask us, on a postal, for booklets on any of the above. Professiorv * Zeos Sphygmomanometer, Pocket and Office types. Jeos Urinalysis Glassware. Zeos Fever Thermometers. Bulletins on request. cos lem | “INDICATING + THE SIXTH SENSE OF INDUSTRY erature Instruments RECORDING + CONTROLLING © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 19.

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rom Saw Mill tO Bungalow —WHEREVER MEN DEPEND UPON CUTTING TOOLS MOST

Simonds Circular Saws are the favor Hand skilled Both Simonds ites in the big mills. Simonds Saws are first choice among carpenters and other craftsmen. mills and craftsmen choose Saws because they want perfect cut ting qualities in any they use And they know that a Simonds Saw can cnly be produced by Simonds Saw They know, too, that a characteristic Simonds cutting edge is made pcs only by using the specially leveloped sible processed steel, C nearly your hardware or mill supply deale: for these saws or write us for catalog SIMONDS SAW Fitchburg, Mass. “The Saw Makers” Branch Stores and Service S! enounced S!I-MON SAWS FILES KNIVES STEEL

} through a century of experience. Ask & STEEL COMPANY Established 1832 : Principal Citic SIMONDS

IS) This seal on a radio or tool advertisement signifies the approval of the POPULAR SCIENCE MONTHLY

Mie? lone Worksop nique Boxing Doll Game “Fight” by Manipulating Small Figures

Contestants

A pair of boxing dolls ready for a battle. Their arms ere controlled by the contes- tants, whoput them throucghthe motion of fighting and endeavor to punch in the pins

At left—Dressing a papier “~ 44 . . mache doll in trunks and insert ing one of the markers which are designed to register blows W O papier-maché dolls, four of wire, glass-headed pins, if cut short, will serve as well. The lowest of the three photographs shows one of the targets about to be inserted in a boxer’s forehead. The gloves are made of putty and mold- ed on the boxers’ fists; Practice and quic kness of hand and eye are necessary to “down” the opposing boxing doll by punching home the three little buttons. KENNETH B. MURRAY. Those who have been following Edward E. de Lancey’s series of model- pieces some nails and putty and cloth, all not costing more than 10 cents, can be made into an amusing boxing game. The arms of the dolls ated by the two contestants. Each tries to win a are oper “knock- out’? by manipulating his boxer so that it each of the three buttons exhibited by the opposing doll pugilist. The dolls, as purchased from the variety store for 15 cents each, are dressed in white tights and black trunks. Nails with putty buttons molded on the heads as the targets and indicators. Large punches in that illness has delayed temporarily the preparation of the concluding article. serve To Keep Rats from Brooder House

ROWN rats, which destroy dishearten- ing number of small chicks every season, make their nests un- derthe wooden floors of brooder houses. To keep the rats out, a satisfactory meth- od is to remove the floor, being careful not to damage the boards, and remake it in sections similar to batten doors. : SOLID FLOOR A brooder and hinge the vari- ous sections to these border pieces. The sections then can be raised instantly and rats routed out and their nests de- stroyed. Another advan- tage of having the floor in sections is that when the house is not in use, they can be raised, thus keeping the ground

house, | If the building is EFS os —— ang 6aty and thereby ' small, one door or &S ne, <= ; diagram of typical preventing the de- section on each side = SS “LS arrangement of cay of the founda- will be sufficient; if ss ra hinged flooring tion timbers and the large, make one for each and end, leaving occupied by the brooder nailed to the floor timbers. Nail one board securely at each side and floor. The cost need side that part not stove solidly —J. R. KOONTZ, Bremen, Ind.

September, 1925 making articles will be sorry to know end of the building | be more than the price of the hinges required, a little lumber, and a few nails. The work itself can be done in spare time.

Septe =| | |

INSTITUTE OF STANDARDS. See page 19.

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September, 1925 No. 486 Eveready Layerbilt ““B” Battery. 45 volts. Length, 8 3/16 inches. Width, 4 7/16 inches. Height, 7. 3/16 inches. Weight, 14% pounds. Price, $5.50, POPULAR SCIENCE MONTHLY plate. It’s all battery. With every cubic inch packed to capacity, it con- tains about 30 per cent more electricity- producing matertal. All chance of loose or broken connections avoided by contact of full area of carbon plate against zinc The scientifically correct construction. The greatest improvement ever made in ABSOLUTELY new in construction—per- fected through years of research, the new Eveready Layerbilt “B” Battery is as superior to the old type “B” Battery as a tube set is to a crystal. Heretofore, all dry ‘“B” Batteries have been made up of cylindrical cells —no one knew how to make them any other way. The new Eveready Layer- bilt is made of flat layers of current- producing elements compressed one against another, so that every cubic inch inside the battery case is com- pletely filled with electricity-producing material. Layer-building heightens eff- ciency by increasing the area of zinc plate and the quantity of active chemi- cals to which the plate is exposed. After the most rigid laboratory tests, more than 30,000 of these new Ever- eady Layerbilt “B” Batteries were manufactured and tested by use under actual home-receiving conditions. These tests proved that this new battery is far superior to the famous Eveready Heavy-duty Battery No. 770, which up to now we have ranked as the longest lived “B” Battery obtainable. On 4-tube sets, 16 mil drain, it lasts 35% longer. On 5-tube sets, 20 mil drain, it lasts 38% longer. On 6-tube sets, 24 mil drain, it lasts 41% longer. On 8-tube sets, 30 mil drain, it lasts 52% longer. “B” Batteries The new Layerbilt principle is such an enormous stride forward in radio battery economy that we will bring out new sizes and numbers in this Layer- bilt form as fast as new machinery is installed. For the present, only the extra-large 45-volt size will be available. Buy this new Eveready Layerbilt No. 486 for heavy drain service. It far exceeds the performance for which Eveready Radio Batteries always have been famous and is, we believe, by far the most economical source of ‘“B” current obtainable. Manufactured and guaranteed by NATIONAL CARBON CO., Inc. New York San Francisco Canadian National Carbon Co., Limited, Toronto, Ontario EVEREADY HOUR EVERY TUESDAY at 8 P.M. Eastern Standard Time Beginning Sept. 29th, 9 P. M. Eastern Standard Time | For real radio enjoyment, tune in the ‘Eveready Group.” Broadcast through stations— WEAF NewYork WGR Buffalo WWJ Detroit } WJAR Providence WCAE Pittsburgh we Minneapolis | WEEI Boston WEAR Cleveland co { St. Paul WFI Philadelphia WSAI Cincinnati WOC Davenport Radio Batteries ~they last longer seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 19. 91

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92 Your

Hammer If youre particular THE DAVID MAYDOLE Norwich, about your tools When you grip a Maydole you feel as if it was made specially for you. No other hammer has its mar- velous ‘“‘hang’’. It’s the result of eighty-two years of pains- taking development. And the Maydole has a strength and stamina that’s worthy of its design. The head is of press-forged steel, tempered separately at each end for the particular work it is to perform. The handle of clear second-growth hickory, air-dried for years. It’s made tight and it stays tight. For real hammer service and satisfaction, make sure that “PD. Maydole”’ is stamped on the head of every hammer you buy, whether it’s a nail ham- mer, machinists’ or any other type of hammer. Your dealer will gladly show you the Maydole you need. Write for free pocket handbook A fea «al

lf AMMER

am mers/ 1843

© This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. HAMMER CO. New York Maydole / fi VX . POPULAR SCIENCE MONTHLY September, 1925

| ing and minor repairs himself, will | appreciate the toolbox arrangement

Me Wlonmne WorlksSinc Do ) ¥e/

By H. T. Shrum Instructor of Auto Mechanics State Normal School, Oshkosh, Wis.» NY one who has toured the / country much and has taken care of his car, doing the oil- | illustrated, especially if it is possible < : | small sheet-metal box in which the

| 1t was not necessary : was needed, all tools

| piece of 6-in. to install a similar one in his own machine. For two years the writer had a most used tools were kept. So that it would be handy for changing a tire or to make some slight repair, it was kept on the floor board just under the edge of the front seat. When, the spare tire

Handy Toolbox for Your Car

including the jack were available and for the occupant of the other front seat to move in order to get at the tool com- partment under the

The box dimen- sions, of course, depend upon the opening available. In this case the box is 4 in. deep, 534 in. wide and long | enough to receive | the jack handle, or | 14 in. The box is con- structed very sim- ply of 28-gage gal- vanized iron, bent up at the bottom and end corners and well riveted.

Simply made There times, however, when the open tool box was in SLIDE na the way or the GALV.IRON tools seemed un- toolbox duly exposed to strangers when the car was parked. For these reasons a box was made to slide under the front seat, after the block which closed up this space had been removed. were

How the and slide are made sheet-metal slides under the front seat of an automobile toolbox that A 3/16-in. strip or “hem” is folded over to strengthen and finish the top edge. A handle on each end is provided so that the box may be carried to the work after it has been withdrawn from the slide. The slide is built much like a box lid, open at one end and with a hem turned on the edges to finish and strengthen them. It is riveted at the corners and then screwed or tacked in place to guide the box under the seat and keep it in place. The tools “ie be kept from rattling by lining the box with enone |

Mailbox Supported by a Swinging Arm | URAL mailboxes that can be swung R to the side of the road have three advantages: They can be turned out of the way when the highway is being graded, they are not apt to be broken off by the passing of an extra large load of hay or grain, and in snowdrift time they can be swung to the most access- ible point of approach. The support illustrated is made of a well casing 2 ft. long, with three circular notches in one end to serve as seats for the swinging arm. The casing is set in a concrete base with the bottom end open to allow for drainage. The arm is 114-in. well pipe, flattened where the box is bolted on and screwed at the bottom into a discarded well cylinder, which is filled with concrete as a weight.—A. C.

See page 19.

Septe

Gent ment Nam Addr Coun

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ee a a a! oe oa bo ~ > f OZARKA SERVICE We Have Openings for a Few More Ozarka Factory Representatives ZARKA Incorporated, is now entering its 4th year. From a beginning with one engineer, one stenographer, one salesman —our present president, the Ozarka organization has grown to over 3100 people. There must be some good reason for this growth. Ozarka instruments have made good—they have more than met competition. Ozarka representa- tives have made good not only because Ozarka instruments were right, but because they have been willing to learn what Ozarka engineers wer2 willing and capable to teach them—Ozarka un- usual salesmanship and Ozarka service. There are still openings for the right men in this organi- zation—men who believe in the future of radio—men who are tired of working for some one else—men who want a business of their own. Prove yourself by sales and will- ingness to learn and exclusive territory will be given you. The man we want has livedin his community for some time. He has the respect of his fellow men because he has never “put anything over’’ just to make money. He may not have much money, but he is not broke and is, at least, able to purchase one demonstrating instrument, Check Coupon for FREE Selling Book Radio offers a wonderful opportunity to men who are will- ing to start at the bottom and build. You need not know salesmanship, but will you learn what we will gladly teach gueseemeeeeee you? You may not know radio, but we The can and will teach you if you will do your part. With such knowledge and willingness to work, it doesn’t seem possible that you cannot make good. Sign the coupon below, don’t fail to give the name of your county. Better still write a letter, tell us about your- self and attach the coupon. If interest- ed_in our salesman’s plan ask for ‘Ozarka Plan No 120R. (Nco RPORATED 120 Austin Avenue R Chicago, Illinois

93 Gentlemen: I am greatly interested in the FREE book “The Ozarka Plan’”’ whereby I can sell your radio instruments, Gentlemen: Without obligation send book ‘‘Ozarka Instru- ments No. 120 R’”’ and name o1 Ozarka representative.

EMMMNEE OG )asracinis trie Odea a ainea aes oowe een aa recedteneeneeasekeeas PRMD Jess Laeta dag tebad dnewese aes eae saasconedeanaaaa’ | WURDE «sass 00s ses carbswaswaeceseeuasne CMP csraccinascensds MEER So. ictcedcaodeaceueautassa uous CAN ci cedccsdvaneeanne } ‘ — SERIE cca cenaencAbaadeicsceauaeassus's SiR ie ca ccickvaveassoess CORE oss adode aces ce aes aecaen GOR ec cantseciee ecccce

© This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 19.

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POPULAR SCIENCE MONTHLY September, 1925. A Necturne Played to the Pensive Night Softly the shadows overtake the day. Comes dusk, then eve- ning. Celestial. torches shed their faery light as a dreamy melody sings to the night and tothe stars. An artist, in med- itative mood, plays in your very living-room. Such is the joy that Radio brings—per- fect if Rauland-Lyric is used to amplify for this instrument transmits with utmost fidelity every detail of the rendition. Rauland-Lyric is a laboratory- grade audio transformer de- signed especially for music lovers. The priceis nine dollars. Descriptive circular with am- plification curve will be mailed on request. All-American Radio Corporation, 4201 Bel- mont Ave., Chicago. The Choice of Noted Music Critics T LITTLE cost it is possible to build A a simple air-coaster that will furnish safe and thrilling sport for children. Two posts of l-in. pipe are set up as far apart as possible, preferably about 50 ft., one projecting about 5 ft. above the ground and the other 3 ft. 6 in. These are guyed with wire and a 3/16-in. wire is stretched between them at the top. On Front and side views of the aerial car and the top of one of the posts for Small Children this runs the car, which is made ag detailed. While the car can be pushed back to the high end of the line after each trip, it is more fun if a more mechanical method of return is provided. A good way to do this is to fasten a wooden tube, such asa package-carrying handle, to the car by means of a chain or heavy cord and run through it a length of \%-in. wire. This wire should be fastened to each post by means of an extension bolt and a spring should be placed at one or both ends. By using the wooden handle it is pos- sible to obtain a snubbing grip on the }- in. wire so that the rider can pull himself back easily with his right hand. The grip also serves as a brake on the down- ward trip. The details of the construc- tion are illustrated fully at the left.— DONALD W. CLARK. ATS of great durability, as well as M sewing stands and ornamental bas- kets, can be made from corn husks. Let the husks from several dozen roast- ing ears or ears of field corn dry until the green.color is out of them. They should not be so dry, however, as to break when bent. If too dry or old, they should be scalded with hot waterand used while still slightly damp. Six steps in making the preliminary braid of com- mon, dried corn husks Take three small bunches of the husks, tie them together 2 or 3 in. from the large end and start braiding them, preferably in a three-strand braid. Add a new bunch whenever an end becomes too short, placing it right on top of the short end. pp % 6 This will be about every other fold on Mats and Baskets Made of Corn Husks YW CORN-HUSK BRAIDS SEWED § TOGETHER short husks. Let the heavy end stick out above the work about 2 in. each time. For an ordinary door mat a braid about 16 ft. long is necessary. To com- plete the mat it is necessary merely to coil the strand up to make a circle, oval, or rectangle, as de- sired, sewing the turns to- gether with strong thread .and a_ large needle. For a square mat, it is a good plan to carry the (Continued on page 106) The braids are sewed to- gether to form baskets or floor mats © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 19.

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le as ‘0 the it is od of 0 do Lasa ir by 1 run st by pring pos- e mself The own- truce ft.— k out e..., oraid com- > coil 1, or is de- wing vith read large or a t, it plan When Children Ask The plaintive request of the little child for a doll,a wagon orsome simple toy is the most touching thing in the world. Gladly you will deny your- self so that you can satisfy the want of the child. And we would not have it otherwise. For childhood takes its pleasures with inex- nsive toys—things that we should be able to give them. _ The message we would like toimpress is that you can have the things you need and give your children the things they would like. The way 1s easy. Itis only necessary to buy right. “Thrift is common sense applied to spending.” The Sears- Roebuck way is the sensible way. We guaran- tee to save you money. Already we are serving nine million homes, or more than one-fourth of all the families in the United States. Sears, Roebuck and Co. have become the World’s Largest Store be- cause we lead in service, in quality andinsaving. Webuy inimmense quantitiesand sell directto you. Wesellonlyqual- ity merchandise, the kind that can be honestly guaranteed. Our New Big Catalog for Fall and Winter is ready for you. It shows 35,000 opportunities to save on everything you need for the family, the home and the farm. Sears, Roebuck and Co. PHILADELPHIA . CHICAGO . DALLAS . SEATTLE Send for Your FREE Copy If you haven’t a copy of our New Big General Catalog, send for it today. This convenient coupon will bring you free our great Fall and Winter book, with its 35,000 bargains, We own and operate Radio Station Worw’s Lancest Fy ORE W LS. Tune in on 344.6 meters. POPULAR SCIENCE MONTHLY Mail the coupon TODAY to the store nearest you Sears, Roebuck and Co. Chicago Philadelphia Dallas _— Seattle 91P82 Send Latest General Catalog. Name Postoffice. Rural Route Box No. State. Street and No. See page 19. © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS.

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SLSR i Bi nti SEER 2 TR AERO RR ‘POPULAR SCIENCE MONTHLY A Selected Set Snap-on INTERCHANGEABLE SOCKET WRENCHES With Which You Can Repair Your Ford In Garage Style Be ready to fix it quickly in cases of emer- gency on the road—save repair bills—make your car run better and last longer. It is an easy matter to reach and turn the nuts and bolts throughout the Ford car with this remarkable Snap-On Set. There is a special chart which shows the inexperienced owner all of the most important repair jobs. No need for you to be at the mercy of ordinary, inefficient tools when you can get the Genuine Snap-Ons for so little money. Snap-Ons will. pay for themselves a hundred times over, What Car Do You Drive? There is a special Snap-On Set, equally as good for each different make of car. Any Sna dealer is an expert on the tool needs for your car. e can be of real service to you. Snap-On Wrench Company, Mfrs., Milwaukee f Look for the name Snap-On on each handle and socket. It is mot a genuine Snap-On without the name. Motor Tool Specialty Co., 14 E. Jackson Bivd., CHICAGO Gentlemen: Please send me full particulars about Snap-On Set for Ula ies Ai iiadiip sbihn pb aiicnliien dsiun et sonnel car. (If interested in Master By Emanuel E. Ericson Noted Manual-Training Authority 1 Lay one piece in the correct relative position on the other and mark the lower with the point of a knife. Turn the parts over and mark the other piece a Using your try-square and being guided by the marks you have just made, draw knife lines across one broad surface and about one-half the distance across each edge of each piece of wood 3 Set your gage for approxi- mately one-half the thickness of the wood and mark both pieces, in each case marking from the upper surface or working face 5 The cross cuts necessary to remove the waste wood can be made most easily with a backsaw. A wooden bench hook—a board with a _ block screwed on top of one end and beneath the other —is convenient for holding the stock. The wood also can be held in the vise and cut with a fine hand-saw 4 Cut on the gaged lines with a rip- saw, keeping on the side of the lines that is in the waste part of the wood 6 If carefully made, the joint will fit without chiseling and both sides will be even, provided the pieces are of the same thickness. The joint may be fastened with glue and screws, or nailed. It forms a simple yet strong connection & This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 19. Septemb

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POPULAR SCIENCE MONTHLY VERHEATING junks more Fords than long service does. A boiling radiator is a danger signal. It means a power-sapped motor and thin- ned oil that leads to scored cylinders, burned-out bear- ings, and the scrap heap... Protect your sturdy little car with a Blackhawk Water Pump. It will keep your motor at the right heat for peak power and longest life. The Blackhawk “Chief” outpumps all others because of its turbine-type impeller. Other features are its double bronze bearings with double grease lubricators, flanged drive pulley, and extra-husky construction. A Blackhawk Pump is all-year protection. Ends boiling in summer, and prevents freezing in winter by briskly cir- culating the water and stopping evaporation of alcohol. Your dealer can supply you with the “Chief” at $7.50 (Western price $8.00). Or write us direct. BLACKHAWK MANUFACTURING COMPANY (Formerly American Grinder Mfg. Co.) DEPARTMENT L MILWAUKEE, WIS. Pumps Longer Life} | Into Your Ford Turbine Head This exclusive Blackhawk turbine-type impeller delivers more water at all speeds. Here is the best pump at its price on the market. Second only to the ““Chief” in pumping power and has many of its features. Only $5.00 (Western list, $5.50). Both pumps come complete with belt and horn bracket. Flanged Crankshaft Pulley Keeps your Ford fan belt always on the job. Interchange- able with old pulley. All steel and sturdy. Only 75c BLACKHAWK © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 19.

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0 TEBE eta at a ES ad 98 POPULAR SCIENCE MONTHLY This special in- sulation made to order for radio— Now built into a line of low-loss parts The first choice of thousands of successful set builders is Radion Panels —made of Radion, ‘the insulating ma- terial built to order by our engineers for radio exclusively. Now we announce new develop- ments in radio parts made of this perfect insulation that practically re- duces losses in reception to a minimum. These parts have the wonderful Radion finish, smooth and _high- polished. This finish eliminates those losses caused by moisture gathering on the surface of ordinary insulation, caus- ing leakage paths. The high-resistant characteristics found only in Radion Panels also mark these new parts. You can now get Radion Sockets, Radion Dials, the new Radion Loud Speaker Horn, Radion Tubing, Radion Binding Post Strips, Insulators, etc. And, of course, Radion Panels (made in black and Mahoganite) come cut in standard sizes for whatever set you wish to build. Ask your dealer to show you Radion Panels and the new Radion parts. Send for Booklet ‘Building Your Own Set’’ It gives wiring diagrams, front and rear views, shows new set with slanting panel, sets with the new Radion Built-in Horn, list of parts and directions for building popular cir- cuits. Send coupon with 10 cents for your copy. American Harp Russer Company. Dept. F-6. 11 Mercer St., New York City. Chicago Office: Conway Building. Pacific Coast Agent: Goodyear Rubber Co., San Francisco —Portland. Wew No. 10 4- inch Radion Close-Tuning Dial. built to conform to the fingers. RADION @ The Supreme Insulation AMERICAN HARD RUBBER COMPANY Dept. F-6, 11 Mercer St., New York City. Pleasesend me your booklet, ‘‘Building Your Own Set’, for which I enclose 10 cents in stamps. Clutch of the ANY cars have what is com- M monly referred to as the sin- gle-plate clutch. This single plate is fastened on the forward end of the clutch or transmission drive shaft, power being trans- mitted to it from the flywheel. It rides between two friction surfaces or clutch facings. While similar in action and handling to the multiple-disk clutch, the care and adjustment of this clutch are not quite the same. The multiple-disk clutch in some instances is not adjustable and in other cases is adjustable by putting it under the arbor press and pressing the end driving plate down, after which a split collar is moved forward a notch. In other cases the multiple disk clutch is adjusted by taking up on three or more bolts, which compress the clutch springs. The single-plate clutch is adjusted by loosening two setscrews to be found on the clutch cover, which is bolted to the fly- wheel. The two adjusting screws are easily recognized, since they are set in slots. When the screws have been loosened and the clutch has been disengaged by depressing the foot lever and the ad- justing ring inside, the clutch is moved ¥4 in. around to the right or clockwise by tapping either one of the setscrews. After moving them this amount, they are locked in position. If the clutch previously has been ad- justed until no further slot motion is possible, it will be found in most cases that new holes for the setscrews have ap- peared within the slots. A time finally comes, however, when it is no longer possible to adjust the clutch, and, unless the slipping is due to glazed friction rings, the job will have to be dismantled and new friction disks or rings installed. MOUNTING RING AND ADJUSTING BOLT FRICTION DISK Ti SPLINED TO bi oN SHAFT ors PA x COMPRESSION SPRING THRUST RING Cutaway view of flywheel and single-plate clutch showing friction rings and adjusting bolts How to Repair and Adjust an Auto Single-Plate Type It sometimes happens that the friction rings allow the clutch to grab or slip, yet are otherwise in good condition. In such cases it is well to wash out the clutch, Remove one of the adjusting screws and pour in \% pt. of kerosene. Replace the adjusting screw and start the motor. Allow the motor to rua slowly from 10 to 15 minutes, working the clutch in and out as the motor runs. Drive the car on a steep grade or blocks so as to raise the front of it higher than the rear. Turn the flywheel until the adjusting screw is on top, remove it and turn the hole down so that the oil may drain out. If possible, allow the car to rest in that position overnight. If it is found that the clutch still grabs, a small amount of lubricating oil may be squirted on the plate and friction disks. Use just enough to moisten the friction disks. The latter method of treating a clutch may pe used to relieve grabbing when it is not possible to wash it out thoroughly. If it is found necessary to reline the clutch, which in this case is merely installing the new clutch friction disks— they are not fastened as are the multiple- disk clutch facings—the first step is pulling the transmission. The method of proceeding in this work was outlined in an article on relining clutch disks in the May issue of POPULAR SCIENCE MONTHLY (page 92). When the transmission is pulled the clutch is left in the flywheel. To facili- tate the work a block about 1% in. high and 4 in. long is used to block out the throw-out yoke. After the cap screws holding the clutch assembly to the fly- wheel have been removed, the clutch assembly will come away easily. Before removing it, however, prick punch some identification marks on the cover and fly- wheel to insure proper reassembly. In all clutch disassembly and reassembly work the most difficult part is compressing the spring. Facilities at hand will de- termine the method to be used. The (Continued on page 108) © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. ——— See page 19. & Fa

Page 87

from 10 h in and rade or it higher eel until emove it e oil may 1e car to ill grabs, | may be yn disks, - friction eating a prabbing h it out line the merely . disks— nultiple- step is ethod of .ed in an the May [ONTHLY lled the ‘o facili- in. high out the ) screws the fly- » clutch Before ch some and fly- : ssembly pressing will de- 1. The $$$ Get This Modern fast Charger Eats ——— Better Because:— New micrometer adjustment, hinged lid, and carrying handle. No bulbs to buy or break. Can be used anywhere—con- tains no acids or other harmful liquids to spill. Approved by underwriters— trouble-proof, shock-proof and fireproof. Beautiful cabinet in maroon and gold. Write for new edition of our instructive booklet on ee radio operation “The Secret of Distance and Volume in Radio.” —— POPULAR SCIENCE MONTHLY IS) gone; ’ he ert taioned ay th the s low Z-ampere rie te is obsolete” charger ! ”~ Over 500,000 already in use When you buy a charger don't let anybody sell you an obsolete, slow 2-ampere model. The New Improved GOLD SEAL HOMCHARGER, with its full 5-ampere rate, charges your battery over- night! Does away with the long bothersome waits that were necessary when the slow inefficient chargers of last year were the best that radio offered. And the New Improved GOLD SEAL HOM- CHARGER charges both A and B batteries with- out additional equipment. Be sure when you buy that you get a modern, fast charger, with a 5-ampere rate. To be absolutely sure, insist on the GOLD SEAL HOMCHARGER. The Kodel Radio Corporation 500 East Pearl Street - Cincinnaci, Ohio Owners of Kodel Broadcasting Station WKRC on the Alms Hotel. Send for program. ‘ ® This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 19.

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“ATKINS” Always Means Quicker, Easier Metal Cutting! OU—whenever and wherever you cut metal—can save time and money by using genuine Atkins ‘Tungsten Alloy” Hack Saw Blades. The Atkins Hack Saw Chart—free—tells the right Atkins blade for every metal cutting job, tosave you time, money and material. The name ATKINS on the blademeans the highest grade “‘Tungsten Alloy’’ steels chosen by the great Atkins laboratories, tempered by the exclusive Atkins gas and oil process, “‘file tested’’ to prevent breakage and insure extra life and value. Ask YOUR Hardware Dealer for genuine ATKINS “Tungsten Alloy AAA’’ Hack Saw Blades, “All Hard”’ r ‘““Non-Breakable.”” We'll gladly send you the Atkins Hack Saw Chart and our valuable booklet ‘ ‘Atkins Saws In The Shop.” E. C. ATKINS & CO. Established 1857 Leading eng oer gat of 7 Saws, Saw Tools, Saw \) Specialties and Machine fj Knives. INDIANAPOLIS, U.S. A. ATKINS TUNGST Wer SAWS POPULAR SCIENCE MONTHLY so I built the saw illustrated. Only after having put it to use did I re- alize how much time such a ma- built of straight-grained hard wood bolted together. and down between vertical guides in the main frame. frame, which is designed to be at- tached to any convenient post, carries a table; this should be about 2 ft. square, supported on brackets exactly at right angles to the back board and, if necessary, reinforced J with braces underneath, as shown |} in the photographs. ; crank at one end and a pulley at the other runs in two bearings fastened at the lower end of the back board. HILE making a wooden pattern recently I found a jigsaw was indispensable, chine will save in a small shop. The jig frame or saw carrier is It can move up The main A short piece of shafting with a Side view of machine, plan of saw table, and details of saw guide and fastenings The jigsaw as assembled (at Jeft) and how it is used (at right) A short connecting rod connects the crank with the jig frame. A small strip of brass is embedded in the table top to act as a guide for the saw blade. It prevents the saw from bending and breaking if the work is pushed against the blade too viclently. At the upper end of the jig frame is fastened a heavy piece of sheet metal cut and bent as shown in detail. The slot in this piece allows the saw blade to be adjusted so that it will be perpendicular with the table. To this metal bracket and to the Icwer arm of the jig frame are bolted threaded rods, each one being cut with a hacksaw, as shown, to receive and hold the end of the saw blade. An ordi- nary heavy coping-saw blade is used. The table top should be sandpapered and varnished or oiled so that the work will slide freely, and the remainder of the machine should be painted. The pulley may be belted to a small electric motor or to any convenient source of power that will run the saw at a high speed. —JONAS J. BYBERG. How to Steam or Boil OW to steam or boil long strips of wood to get them into condition for bending is sometimes a puzzling problem. One simple solution is illustrated. From a junkman obtain an old steam boiler tube or even a galvanized-iron rain- water conductor pipe, which will answer well enough if the seams and joints are water-tight. Close one end with a round wooden plug. Stand this end in a shal- low hole in the ground and pack the earth around it firmly enough to hold it upright. Put a little water in the pipe if the strips are to be steamed; fill it, if they are to be boiled. Insert the wood, place a flat stone on top of the tube, and build a fire around the base. There will be no danger of an explosion, as a small amount of pressure will raise the stone on top.—JAMES E. NoBLE, Toronto, Can. Long ae of Wood Steaming strips of wood that are to be bent © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 19.

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led (at Jeft) (at right) the crank redded in r the saw 1 bending 3 pushed frame is metal cut he slot in le to be endicular bracket Tame are being cut -eive and An ordi- 3 used. ipapered the work er of the 1e pulley ¢e motor f power h speed, 90d = BY) be bent es ~ Radio FOR THE CIRCUIT TheBalxue Battery Charger The most popular battery charger onthe market. It can be used while the radio set is in operation. If the battery should be low you merely turn onthe charger and operate the set. Charging rate 2.5 amperes. Op- erates from 110-120 AC 60 cycle current. Special model for 50 cycles. Price $19.50 West of Rockies, $20 Slightly higher in Canada The Balkite Trickle Charger Charges both 4 and 6 volt radio “A” batteries at about .5 amperes. Usable in 3 ways: (1) As a regular charger with a low capacity storage battery for sets now using dry cells. (2) With storage battery sets of fewtubes. Furnishes more current than used by 6 dry cell or 3 storage battery tubes, so that if used dur- ing operation it need be used at no other time. (3) As a “‘trickle” or continuous charger for storage battery sets of as many as 8 tubes. Sizes 5% in. long, 2% in. wide, 5 in. high. Operates from 110-120 AC 60 cycle current. Low capacity batteries especially adapted for use with this charger are being offered by practically all eens battery manufacturers this Reputable manufacturers are also offering this fall for use with this charger special switches which turn on Balkite “B’’ and turn off the charger when you turn on your set. This n.akes the current supply for both “A” and “B’’ circuits automatic in operation. Price $10 West of Rockies, $10.50 Slightly higher in Canada . BALKITE BATTERY CH POPULAR SCIENCE MONTHLY Balkite Balkite Radio Power Units are the ideal power supply for any radio set. They simplify and im- prove radio reception. They reduce the amount of attention you must give your set. With their use your current supply is always exactly what is required for each circuit. For the “A” circuit there are the Balkite Chargers, Because of its obvious advantages the Balkite Battery Charger is the most popular charger on the market. En- tirely noiseless — it is the only charger commonly used while the set is in operation. For sets of smaller “A” current requirements—any dry cell set or sets of few storage battery tubes—there is the Balkite Trickle Charger. W ith a low capacity storage battery it enables owners of sets now using dry cells to make a most economical installation. For the“B” circuit there is Balkite “B”—the outstand- ing development in radio. It eliminates “B” batteries en- tirely and supplies plate current from the light socket. It fits any set of 5 tubes or less. For sets of six tubes or more there is Balkite “B” II, the same popular model offered last year. Noiseless—No bulbs—Permanent All Balkite Radio Power Units are based on the same principle. All are entirely noiseless in operation. They have no moving parts, no bulbs, and nothing to adjust, break or get out oforder. They cannot deteriorate through use or disuse—each is a permanent piece of equipment with nothing to replace. They require no other attention than the infrequent addition of water. They do not in- terfere with your set or your neighbor’s. Their current consumption is remarkably low. Theyrequire no changes or additions to your set. They constitute the most ad- vanced power equipment on the market, one that is economical, unfailing in operation, and eliminates the possibility of run-down batteries. Manufactured by FANSTEEL PRODUCTS COMPANY, Inc. North Chicago, Illinois FANSTEEL © Balkite Radio Power Units ARGER + BALKITE TRICKLE CHARGER ° BALKITE“B” - (Cixi i BY © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 19. | Power Units the ideal power supply for any radio set FOR THE CIRCUIT Balkite “B” Eliminates “‘B”’ batteries. Supplies plate current from the light socket. Operates with either storage bat- tery or dry cell tubes. Keeps “‘B” circuit always operating at miaxi- mum efficiency, for with its use the plate current supply is never low. Requires no changes or additions to your set. No bulbs—nothing to replace. Requires no attention otherthan adding water about once a year. A new model, designed to serve any set of 5 tubes or less. Size 8% in. long, 8 in. high, 3 4 in. wide. Occu- pies about same space as 45 volt dry **B”’ battery. Operates from 110- 120 AC 60 cycle current. Price $35 Slightly higher in Canada Balkite “B” II The most outstanding develop- ment in Radio last season. Same as the new Balkite “B” but will fit any set including those of 10 tubes or more. Current capacity 40 milli- amperes at 90 volts. Size 9 in. high, 6% in. wide, 7% in. deep. Operates from 110-120 AC 60 cycle current. Special model for 50 cycles. Price $55 Slightly higher in Canada = The Unipower, manufactured by the Gould Storage Battery Com- pany, is equipbed with a special Balkite Radio Power Unit. BALKITE “B” Ii

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An Easy Way to Learn PHARMACY AT HOME Graduate pharmacists are al- ways in demand. The work is in- teresting and pleasant and salaries are good. Many young men open drug stores of their own and be- come independent. There’s an easy way to learn pharmacy right in your own home in spare time, without losing a day or a dollar from your present work. The International Correspon- dence Schools course in Phar- macy supplies the knowledge which it will be necessary for you to have in order that you may pass your State Board Examination. Just mark and mail the coupon printed below to the International Correspondence Schools, Box 7665-D, Scranton, Pa., and full particulars about the Pharmacy Course or any other work of your choice will be sent to you by re- turn mail. INTERNATIONAL CORRESPONDENCE SCHOOLS Box 7665-D, Scranton, Penna. Without cost or obligation on my part, please tell me how I c1n qualify for the position or in the subject before which I have marked an X [) PHARMACY BUSINESS TRAINING COURSES Business Management Salesmanship Industrial Management Personnel Organization Traffic Management ng Business Ww (J Stenography and Typing Banking and Banking Law J Business English Accountancy (including C.P.A.) (J Civil Service Nicholson Cost Accounting (J Railway Mail Clerk Bookkeeping J) Common School Subjects Private Secretary (J High School Subjects Spanish O French CJ Illustrating TECHNICAL AND INDUSTRIAL COURSES Electrical Engineering 0 Architect Electric Lighting CjArchitects’ Blue-prints Mechanical Engineer Contractor and Builder Mechanical Draftsman Architectural Draftsman Machine Shop Practice Concrete Builder Railroad Positions Structural Engineer Gas Engine Operating Chemistry Civil =ngineer Automobile Work Surveying and Mapping Airplane Engines Metallurgy O Mining Agriculture and Poultry Steam Engineering [1 Radio Mathematics POPULAR SCIENCE MONTHLY enhanced greatly by the addition of cove cornices. As ordinarily built, with the molding put up in single lengths, a high degree of skill is required to obtain good results, but by modifying the design to permit of splicing, the job may be simplified. yi ¢ Figures given here are for the use of 8- in. cove molding made from rough stock 11% by 8 in., but the principles of con- struction are the same for narrower molding. Measure out from the wall plates 11 in. and strike lines by chalking a string, stretching it tightly between the given points and twanging it against the ceiling. Strike other lines 21% in. from these running parallel to the ceiling joists, or about 81% in. from the wall plates, and carefully remove the plaster between the lines and the walls by cutting and chipping out with a cold chisel. With a compass saw cut off IVING- and dining-rooms often are Easy Way to Build a C ornice straight edges on the chalk lines. Use eightpenny finishing nails, and keep ag many as possible behind the gaged mark, where the overlapping cove will cover, Scrape out any hammer marks that appear outside of the line. the laths to the line. Now cut a pine “two by four’ 6 in. longer than the width of the room and slip it up through the opening thus made. Nail the ends to _ the plates with the crown edge up and then nail to it all the By means of two sticks measure the length of the room mie) **3) 6 in. below the ceil- aed | ing and cut pieces of | ‘| cove molding X in, shorter than the exact measurement, The upper edges may be cut back still farther to pre- vent them binding against the adjacent walls. Nail up the loose lath ends. If the backing joist in the corner can be removed, it will serve in place of a new piece. The purpose of this joist is to offer support for the upper member and cove of the cornice. Plane straight one edge of four pieces of 1 by 3 in. S4S (surfaced four sides; that is, finished all over) stock of the wood chosen for the cornice and, of course, corresponding with the rest of the trim of the room. On the face side gage a line 1 in. from the jointed edges. Miter these pieces around the ceiling, keeping the appearance of a li CEILING JOISTS~ ia BACKING JOIST =F SPLICE IN = =f COVE Persons residing in Canada should send this coupon to the international Correspondence Schools Canadian, Limited. Alontreal Canada How the cornice is applied; a cross section, showing the backing joist, the ceiling strip, the cove molding, and the picture molding; and details of a coped corner joint and a central splice A neat cornice often greatly improves the ea STUD tS 4S Ye PICTURE oe MOLDING —_/{ARms cove, tacking the upper edge to the | by 3 in. members on the ceiling and the lower edges to the stud- ding. This allows of pulling the nails for readjustment before the cove is nailed up solidly afterward. To find the studs, tap the walls lightly and locate one stud posi- tively by driving nails through the plas- ter, where they will hide behind the cor- nice. Then measure points 16 in. apart. Next build a miter box about 8 in. wide and 8 in. deep, by nailing sides of 1-in. stock on a bottom of 2-in. material, (Continued on page 107) ving- or dining-room JOIST GAGE DISTANCE WITH *%g° WOOD STRIP tS} This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See Page 19. You answet becaus the di Man : marka facts ; easily

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zed mark, ill cover, rks that asure the the room 7 the ceil. Pieces of er edges cut back or to pre- 1 binding » adjacent ail up the king the > to the | >mbers on the stud- » nails for nailed up studs, tap stud posi- the plas- 1 the cor- in. apart. out 8 in. x sides of material, mut he cove splice po as ——— | POPULAR SCIENCE MONTHLY Into THIS one brilliant book of 280 pages have been condensed the outstanding facts that scientists have discovered since Aristotle, the father of science, dissected a frog to see what made its heart beat. How often have you wanted to know about the won- derful discoveries in science that have so changed the world we live in... the secret of radium... the romance of the atom . .. the origin of the earth! Or you may have wanted to know why glass is trans- parent .. . how fireflies produce light . . . why the grass is green, .. if radio waves move in a straight line? All of these questions, and hundreds of others, have now been answered, for the first time, in one book— THE POCKET GUIDE TO SCIENCE. And you can get this wonderful book absolutely free! All that you probably will ever want to know about science is told in this one book that will fit in your pocket or grace a library table. The curiosity-satisfying facts about the world we live in are made instantly available to you in simple question-and-answer form in THE POCKET GUIDE TO SCIENCE, =| Your Name in Gold ~on this Vonderful Book You are assured of the accuracy of the answers in THE Pocket GuipE To SCIENCE because it has been edited by Dr. E. FE. Free, the distinguished author of “The Story of Man and His World.” Dr. Free has a re- markable genius for condensing the known facts about scientific questions into vivid, easily remembered paragraphs. FREE THE POCKET GUIDE TO SCIENCE is not for sale. It is offered to you absolutely free with a 14 months’ subscription to POPULAR SCIENCE MONTHLY. In Tue Pocxer Guive To Science you pet full information of all that the scientists ave discovered up to the summer of 1924. Poputar Science Montu ty “carries on” where THE Pocket Gu1pDE To SciENCE leaves of, The Pocker Guipe gives you all the information up to right now— Popuar Science Montuty will give you all the im- portant, interesting and new discoveries of science for the next 14 months. In every issue of Poputar ScIENCE ONTHLY are a dozen or more important arti- cles that explain and picture the most fascinat- ing and significant new developments, dis- coveries, and undertakings in exploration, PopuLar ScIENCE MONTHLY, 250 Fourth Ave., New York in engineering, in health, in electricity, in medicine, and in every branch of science. And there are also, in every issue, a hun- dred or more articles describing the impor- tant new inventions in every branch of A Few of the Hundreds of Questions Answered in the POCKET GUIDE TO SCIENCE Why does static interfere with radio messages? What gland makes people grow tall or keeps them short? Why do we grow old? What is the safest stimulant? What is the function of the liver? Why are tears salt? Can energy be destroyed? Why can’t you skate on glass if it is smoother than ice? How do self-winding clocks work? Why does an iron ship float? Can we see atoms with a microscope? What are electrons? Is electricity a form of matter? What is a crystal? How large is the universe? Why do the stars twinkle? How do we know what the stars are made of? Is the inside of the earth molten? What is an electric spark? What makes the noise of thunder? mechanical activity—page after page filled with photographs and descriptions that show you how you can save money in the shop, around your car, in your store, office and home. But all this is only part of the contents of one issue of the amazing Poputar SciENCE Montuty. It takes over 300 articles and pictures every month to tell the readers of Poputar Science Monrsty all that has happened in the scientific, radio, mechanical, and automotive fields. Your Name in Gold We will stamp your name in 22-carat gold on the cover of THE Pocket GuIDE To SciENCE at no extra cost to you if you use the coupon below immediately. You are offered a 14 months’ subscription to Poputar Science Montu ty, regular price if bought by the month would be $3.50, with Tue Pocket Guipe To Science free—all for $2.95, plus the few cents’ postage. If you are already a subscriber to Poputar ScIENCE Montuty we will be glad to extend your sub- scription 14 months if you accept this offer. In using the coupon please PRINT your name SEND Send no money, just the coupon. If within 10 days after you receive the book and magazine you decide that you are not satis- oO fied in every particular you may return them and your entire payment will be re- ONE funded promptly and without question. Address Could any offer be fairer? City Name. POPULAR SCIENCE MONTHLY 250 Fourth Avenue, New York I accept your offer of Toe Pocket GUIDE TO Scrence_and a 14 months’ subscription to Poputar ScrencE Montsty. I will pay the postman $2.95, plus the few cents’ postage when he delivers the Pocket Gute and the first issue of PopuLAR SCIENCE MONTHLY. If the book and magazine are not fully satisfactory to me I will return them within ro days and you are to promptly refund my full payment. Please stamp my name in gold. State

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POPULAR SCIENCE MONTHLY September, Drives Machines Out of the Rut THE common run of machines make commonplace records. But. see those records on Veeder Counters, and you see the place for improvement! You promptly see the im- provement register, by closer watch of the running. You’ get new “leads” to im- proved design, from the indications of production- gains on hie COUNTERS ThissmallRotaryRachetCounter (No. 6) counts reciprocating movements of the lever, as required for recording the output of innumerable small machines. When the lever aa is moved © throughan 4 angle of 40 to 60 degrees, the counter regis- ters one. The further more the lever is moved, the higher the number registered. A complete revolution of the lever registers ten. This counter can be adapted to no end of counting purposes, by regu- lating the throw of the lever. Price $2.00. (Cut nearly full size.) Small Revolution Counter, also $2.00. The Set-Back Rotary Ratchet Counter below is for machines such as presses and metal-stamping machines where a reciprocating movement indicates an operation. _ Registers one for each throw of the lever and sets back to zero from any figure by turning knob once round. Supplied with from four to ten figure-wheels, as re- quired. Price with four figures, as illus- trated, $11.50 subject to discount. (Cut less than ¥% size.) Set-back Revolution Counter of similar model, $10.00 (lis?). Write us about that counting problem of yours—or see how it’s solved in the 80-page Veeder booklet; copy free. The Veeder Mfg.Co. 44 Sargeant St., Hartford, Conn. Y THE application of polychrome finishes that require perhaps less skill than any other method of finishing, you can beautify and rejuve- nate many small pieces of furniture, pic- ture frames, metal objects, lighting fix- tures and other articles. Such a finish will cover up cracks, chipped or tarnished surfaces, and all sorts of blemishes. The lower of the two accompanying illustrations shows a picture frame, two small electric lamps, a clock, a call bell, a piece from a dresser set, a tray and a vase that have been refinished in polychrome and are now quite attractive. Polychrome means tinted with many colors; it is the finish now given to numerous floor and bridge lamps, mirror frames and novel- New Polychrome Finishe, How to Decorate with Colored Bronze Powders Applied by Means of a Cheap Garden Spray By William T. Weld up each chipped place until it matches the rest of the surface. If the plaster become hard or sets before you have finished, may cut or scrape it until the desing shape is obtained. After all defects have been remedied jy this manner, go over the patched plagy with steel wool or fine sandpaper. Noy dust off the entire surface and wipe cle with a cloth moistened with turpentine » benzine. Give each patch a coat or ty of the bronzing liquid or shellac varnish. You now are ready to apply the colored bronzes. m= If you want only one color, simply mx enough of the powder with the liquid t make it about like thin paint. The pr. portion of 1/3 oz. (a level teaspoonful) of . powder to 8 table ties. The finish can be sprayed on with a garden or plant spray of the type having a glass container, usually to be purchased at seed stores for about 30 cents each. Several sprays make for a little faster work, but only one need spoonfuls of liquid will be found quite satisfactory. After stirring this tho. oughly it may h brushed on the frame. be bought provid- ing that several extra containers are obtained. These cost about 10 cents each. The bronze powders may be had in a large number of different colors, but gold, silver, blue, green, red, and statuary bronze will be found to produce about all the variety necessary. These powders are put up in 1l-oz. packages and cost about 25 cents an ounce. Most paint shops carry them in stock. Several small brushes will be needed. ° The bronzing liquid (of the varnish, not “banana oil” type) costs about 50 cents for half a pint. A complete outfit should cost no more than a couple of dollars and with it you can do considerable work. Perhaps there is a picture you wished to frame, but have not done so because of the cost. Almost every home has old framed pictures stored away in the attic or basement. These are often in pretty good shape and need only a little repair work to make them quite presentable. First remove the o!d picture and the glass from the frame and wash the frame thoroughly with strong soap and water. Use an old toothbrush to clean around the corners and the raised places, if there are any. Buy 10 cents’ worth of dental plaster of Paris at any drug-store. Mix about a teaspoonful with a little water until a stiff paste is formed. After wetting the surface upon which this is to be applied, take a small knife and build Spraying the base of an electric lamp and a group of objects finished in polychrome To produce the mottled polychrome effect, however, the spray should be used. Mix your color in the same proportions and place the frame on an old paper o stand it on edge and hang a paper behind it. Your own taste will have to guide you in planning your color scheme. If you wish certain raised portions to be of one color and the sunken portions of another, simply spray the entire surface with the color you desire the raised portion to be. Let this dry for about 30 minutes and then apply the second color. While this is still wet, take a pad made from several layers of cheesecloth and wipe off the entire surface. This will remove the fresh color from the raised surface and at the same time expose your first color. For a mottled effect spray on one color (Continued on page 106) Septemb RELEA HOOK © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 19.

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rpentine oat or two shellac gy r to apply Po simply miz e liquid tp The pro. Doonful) of to 3 table. ls of liquid ound quite ory. After this thor it may be - on the mp and ‘chrome oly chrome d be used, roportions paper or a& paper guide you . If you be of one f another, - with the ion to be. 1utes and While this m several e off the nove the ice and at t color. one color Unique “Butterf up and down Kite String ITE-FLIERS will find amusement in K constructing this novel “butterfly.” It is carried up @ kite string by the wind to a int near the kite where a cardboard disk is located. Upon striking the disk the wings of the butterfly collapse and it slides to the ground. ' The body, of light wood about 4 in. square and 14 in. long, is mortised to a block Yy in. thick and 1 in. square. The wire frame for each wing, which is about 9 in. in diameter, is fastened to the block by means of a piece of light tin secured by cigar-box nails, so that it will fold back easily. ‘The wings are covered with cloth and painted with thick starch. At the end of the body a bent piece of tin with two holes in it is fastened by wrapping CARDBOARD DISK KITE STRING er i bX. RELEASING SLIDING WIRE When the butterfly strikes the cardboard disk, the wings collapse and it slides back to earth with thread and smearing with glue. A hole is drilled in the wooden wing block to correspond to the lower hole in this tin clip. A piece of stiff wire runs through these holes, one end terminating in a hook as shown. The other end projects about 10 in. beyond the block and ends in a right- angle bend. This is the end that goes toward the kite. The kite string passes through a small screweye fastened at each end of the body. Astring tied to the outside of each wing ends ina loop. When the butterfly is set for a flight upward, this loop is caught by the hook on the straight wire. The upward flight of the butterfly is stopped by a heavy cardboard disk, 3 in. in diameter, which is fastened on the kite string near the kite and braced with stiff wires EDWIN G.GETTINS. Metal Corner Pieces Conceal Cracks in Picture Frames J[ARGE picture ioe frames often antl" become unsightly \ TAH because the mi- \\ WAAL HH | tered joints crack NAT open. If the frame is not molded too elaborately, the joints can be con-_—{t cealed with orna-_ [:) mental corner ~W pieces cut from No. 26 gage sheet brass or copper. These are fastened in place by means of small escutcheon pins. The metal may be colored or left bright, as desired.— W. J. E. "26-GAGE SHEET BRASS POPULAR SCIENCE MONTHLY Here’s an Ad that wins men by its fairness Don’t buy yet—wait till the 10-day tube we send you proves its case GENTLEMEN: Palmolive Shaving Cream is today the leader in its field. Yet we urge men not to buy it before they try it. Our whole case rests on a 10-day tube that we send, free, for a test. On that basis we have won the world to this new creation. - Men by the millions are flocking to it. Its success is a business sensation. | Give us ONE chance We realize you are probably wedded to another shaving cream. But, as expert soap-makers (we make Palmolive Soap, you know, the world’s leading toilet soap), we know a fair comparison 80 times in 100 will win you. Palmolive Shaving Cream is a unique creation. There is no other like it. It embodies the four great essentials 1000 men expressed as their supreme desires in a shaving cream—plus a fifth, strong bubbles, the most important of all. 60 years of soap and skin study stand behind it. 130 formulas were tested and discarded before the right one came. 10 days of its delights, we believe, will win you to our side. Now as a courtesy to us, will you mail the coupon and accept those 10 shaves free? 5 New Joys These you'll find—these new shaving joys, these comforts unknown before: 1 Multiplies itself in lather 250 times. 2 Softens the beard in one minute. 3 Maintains its creamy fullness for 10 minutes on the face. 4 Strong bubbles hold the hairs erect for cutting. 5 Palm and olive oils bring one fine after-effects. To add the final touch to shaving luxury, we have’ created Palmolive After Shaving Talc— especially for men. Doesn’t show. Leaves the skin'smooth and fresh, and gives that well- groomed look. Try the sample we are sending free with the tube of Shaving Cream. PALMOLIVE 2953 | ro whe 10 SHAVES FREE =*%4,22,c28, of Palmolive . After Shaving Talc Simply insert your name and address and mail to Dept. B-1058, The Palmolive Company (Del. Corp.), 3702 Iron Street, Chicago, Ill. Residents of Wisconsin should address The Palmolive Company (Wis. Corp.), Milwaukee, Wis. eee eer erec errr eeree esr eeeeerereresereeeseresereresresrereseseseesesereseserereseee F828 © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 19.

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106 What becomes ofthe bassnotes in your set? POPULAR SCIENCE MONTHLY MOMS We Te Neat Desk or Table Stand for Large Dictionary a ss. While the better transformers am- ez plify quite evenly over the entire upper and middle registers of the musical scale, from about cyles downward there is a pro- nounced loss of amplification, as indicated above. Poorer transformers begin to drop off in amplification even higher on the scale with the result that lowest notes disappear entirely. ta, a ae There is no variation in amplifica- oe tion over the entire range of mu- ed. sical frequencies with Thordarson =~ Autoformers. No note is too low—no note is too high to be lost by the Autoformer. three other advantages. Four Great Improvements Full amplification of those bass | notes hitherto largely ‘‘lost’’! Great- er clarity on all signals! Improved reception of distant programs! Better volume control! These are the four advantages achieved by this latest Thordarson development — the Autoformer. Thordarson has succeeded in utiliz- ing, for the benefit of your radio set, the same principle used in the line amplifiers adopted by the more re- cent high-powered broadcasting sta- tions. The excellent quality of these stations (due to perfect amplifica- tion) offers conclusive proof of Auto- former effectiveness. Unconditionally Guaranteed HORDARSO o2alVO 9 wy) AJ, Trade-Mark Registered All Frequency Amplifier Autoformer amplifica- tion is for those who seek the finest repro- duction of programs to be had. used with any set in place of the reg- = ular audio transformer hook-up. Full directions, with diagrams, for building a Thordarson Autoformer Amplifier are supplied with each instrument. Or Write for the Autoformer © Hook-up Bulletin—Just Out! THORDARSON, ELECTRIC MANUFACTURING CO US) Since 1895 WORLDS OLDEST AND LARGEST EXCLUSIVE TRANSFORMER MAKERS 10. Lo. In additicn there are | /4 “4g Wf Uf Wy YY, Y y Hf, Yj j i / / LY) ROSS-WORD puzzles caused the un- abridged dictionary to become better appreciated as a reference book for home use. Its main drawback is its cumber- some size, but that can be minimized by constructing the table stand illustrated. The dictionary then may be consulted without leaving the desk or table.—J. P New Polychrome Finishes (Continued from page 104) and then another until the desired result is obtained. Gold or silver first, then blue, green, and red is a good order. In using the sprays and bronzing liquid in this manner you do not need to wait until each separate color is dry. The only precaution to take is to avoid too much liquid at one time, otherwise the surface will become streaked. You will be delighted with the way the spray of one color blends with another. The best part of applying this kind of finish is that you can’t spoil it. Should you get on too much of any one color, simply tone it down by spraying on a little gold or silver. If you have several small articles of one kind to finish, place them close together while spraying. If you plan to do considerable work, it will be found economical to buy some shellac or ordinary varnish in place of the bronzing liquid. The varnish should be thinned with turpentine and the shellac, if necessary, with alcohol. If you desire a rough surface similar to that on much of the commercial poly- chrome work, a very simple method is as follows: With a brush apply a very heavy coat of what is known as paste wood filler. Do this to the surfaces you want left rough and let it dry for about 30 minutes. Tap this lightly with a stiff brush until it is quite rough. Let it | dry for several days, then sandpaper it very lightly to remove the sharp tips. Let this harden for a week, apply a coat of shellac or varnish, then spray as desired. Household articles on which this colored bronze finish is appropriate are electric fixtures, gas fixtures, shelf brack. ets, wall registers, door-bells, 9 plumbing, radiators, spice cans, bread and cake boxes, candle-sticks, mirror fram metal waste baskets, and book racks Mats of Corn Husks (Continued from page 94) braids back and forth instead of around, Be sure all the husk ends are on the same side, which is to be the top. They should not be cut off except sufficiently to reduce them all to the same length... Th resulting mat will last almost a lif, time, if dried out whenever it gets wet, While these look well in their naturg) color, they are more attractive if colored, This can be done either before or afte making. Pretty effects may be obtained by using several colors alternately when braiding the strands. To color husks, let them stand in ordinary clothes dye for six hours or more. The husks can be made almost pur white by washing them in good strong soap and water in a washing machine, If this is done before dyeing, the colors will be brighter. Be sure, however, to wash out all the soap, if you intend-using dyes, Rugs, mats, and table mats can be made by the same method, except that the husks should be used singly or split into small shreds. All the ends in this cage should be cut off when dry. A sewing basket may be made by wind. ing tightly made braids, with all the ends, cut off, around a form of round or square! sticks. Sew the braid together as the work progresses. The turns go alter nately inside and outside the sticks, a shown. The lid is stiffened with heavy wire reinforcement and has a tassel or ring in the center to serve as a handle, These baskets look best if varnished, —RALPH ALLWINE, Shelby, Ohio. Improving Cheap Jewelry ALTHOUGH heavily gold- or silver. plated in front, some grades d jewelry soon wear down to the brass base on the back. Wrist watches, rings, and other pieces of this kind are apt to leavea black deposit on the skin. The tarnish may be pre- vented, however, by coating the } j Coating back of wrist watch and “‘silvering’’ Be a ring in old “hypo” — back with transparent shellac or varnish. Cheap brass jewelry can be improved in appearance and wearing qualities by suspending it overnight in old, much used “hypo” solution, obtained from your local photographer. The jewelry becomes coated with the silver dissolved in the hypo from photo films and papers.—K. BM FS] This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 19.

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of around, 1 the same P| They iclently to ath. The st a life Sets wet, Ir natural if colored, € or after 2 obtained tely when lor husks, les dye for most pure od strong chine, If colors will r, to wash ising dyes, mn be made that the split into . this case e by wind. ll the ends _ OF square er as the go alter sticks, as rith heavy - tassel or a handle, varnished, hio. welry or silver grades of brass base rings, and to leaves he tarnish be pre- , however, ating the Th K Xo) ) Easy Way to Build a Cornice (Continued from page 102) and sawing through both sides at angles of 45 degrees. Cut four pieces of cove molding 6 in. longer than half the remain- ing sides of the room, and miter back one end of each to get the profile of the curve as a guide for cutting. . ; Cut the curve with a coping-saw held in a plane parallel with the top of the molding; or a narrow, fine-toothed cross- cut saw may be used. With a sharp chisel trim the cut toward the back to make certain that only the surface edges will bear against the mating mold thav already is up. OLD one piece in position against the ceiling, tacking if necessary to re- move kinks, to test the fit with the other cove. If the joint is poor, scribe with a pair of dividers and cut again, or trim the high points with a block plane. When a first-class fit is attained, tack in position and mark the other end at the center of the wall. Fit a length to the opposite molding in the same way and nail up solidly. Finish the remaining wall in the same way. Cut two blocks of 2 by 6 in. stock 8 in. long. Taper these from a width of 5 in. on one end to 31% in. on the other, curving the edge inward for the sake of neatness. Cut a cardboard pattern to fit the curve of the cove, and use it to lay off the edges by which the back of the block may be chiseled. After careful fitting, curve the front face or, if desired, carve a leaf on each for further ornamentation, and nail up with sixpenny finishing nails. Fit similar blocks in the centers of the side coves. Put up the picture molding in four pieces, since the joints are easier made and the lengths may be sprung into place, exerting great pressure at the joints, sufficient to close them in spite of small irregularities. As a gage, hold a 3¢-in.- thick strip of wood between the top of the mold and the bottom of the cove, so that space will be provided for picture hooks. be THE builder feels disposed to put up full-length coves, he should leave the ends of the first pieces a trifle loose, so that pressure from the next piece will spring it to shape against its joint curve. It is also well with such large moldings to put up each piece in succession, so that only one joint is cut on the end of all but the last piece, allowing of a little “give and take” for fitting. Or, the pieces may be put up full length without special care being taken with the corner joints, these being covered with ornamental blocks. If lead wires in loom are tapped from the electric wires and run behind the cove, suitable light fixtures can be put in the corners, hiding the joints and aiding the illumination of the room. In the latter case, however, city ordinances probably will require official inspection.—E. M. L. “How tu Cover Cracked Plaster with Wallboard,’”’ by Edwin M. Love, is one of many helpful articles for home owners scheduled for the October Home Workshop. POPULAR SCIENCE MONTHLY 107 ’ Attachments \ that give your motor more uses pte not equip your motor for drilling, grinding, polishing, and buffing? The Goodell-Pratt small motor attachments make it easy. Just fit any of them on the shaft and the motor is ready to go to work. No. 757 Drill Chuck: Fits motors with 34-inch shaft. Similar to No. 761, but smaller. Holds round shank drills from 0 to 5/32 inch Length 3% inches. Price, $2.00. ad Wel be Te begs. No. 762 Saw Arbor and Buffing Spindle: Has a shank that can be fitted on a %-inch shaft. Arbor takes grinding, polish- ing, and buffing wheels, wire brushes, etc., with 14-inch hole. Flanges open 34 inch. The tapered spindle on the end of the arbor has a deep, clean thread for handling the great variety of wood- centered wheels. Length, 514 inches. Price, $3.00. Saw Arbor No. 758: Similar to No. 762 above, but smaller and without the tapered spindle. The shank fitsa3£-inch shaft and the arbor will take saws or wheels with a 34-inch hole. Opening between flanges, 14 inch. Length over all, 314 inches. Price, $1.50. \ DRILL CHUCK Price, $3.00 Fits motors with 44-inch shaft. Enables you to drill in iron or steel. Three hardened steel jaws hold round shank drills from 0 to 34 inch in diameter. Length over all, 414 inches. FE No. 759 Buffing Spindles: Have a clean, deep, tapered thread for holding wood-cen- tered wheels. They are made with both right and left hand threads. The shank is made to fit a 34-inch shaft. Length, 3% inches. No. 759. Spindle with R. H. threads, Price, $1.00. No. 760. Spindle with L. H. threads, Price, $1.00. Write for Catalog No. 15 See all the other of the famous 1500 Good Tools that Goodell-Pratt make. All are shown in the big general catalog. Write for a copy. It’s free. GOODELL-PRATT COMPANY, GREENFIELD, MASS.,U.S.A. © Makers of Mr. Punch OODELL- PRATT 15300 GOOD TOOLS ? © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 19.

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108 Can one tobacco satisfy a man with 45 pipes? You might imagine that the law of aver- ages would require a man with 45 pipes to smoke a variety of tobaccos. Evidently, it doesn’t work that way, for here is a pipe connoisseur who after vainly trying every tobacco his tobacconist could mention, finally got around to Edgeworth. The result is, his humidor is now ‘‘Edge- worthized.”’ Mr. Sonnenblick makes application for a life membership in the Edgeworth Club. All in favor say ‘“‘Aye.”’ . But first read his letter: Larus & Bro. Co. Richmond, Va. Gentlemen: When a man has 45 pipes he certainly is up against it for an all-round tobacco. But first, about my pipes. There are 2 Dunhills, 6 Comoys, 4 BBB’s, 4 Kaywoodies, 2 Petersons, 2 GBD’s and the usual meerschaum, calabash, corncob, etc. Some were sweet from the start, others remained obdurate and bitter de- spite the fact that I used every American brand and every English brand I could get or my tobacconist could mention. Fancy prices! Hang the price. I wanted pipe satisfaction. The brands I tried failed; the mixtures I made failed because the tobacco varied. I saw the ads written by Edgeworth smok- ers, but they sounded too good to be true. I didn’t try Edgeworth in despair, but just to see how less bad it might be. Well, it’s praise enough when you know that my office humidor has been Edgeworthized. Now my good pipes taste better and my bad pipes taste good. If you've got a life membership open put me down. It’s the King Bee of to- baccos and I think I'm a qualified judge. Respectfully yours, Ira J. Sonnenblick. Let us send you free samples of Edgeworth so that you may put it to the pipe test. If = you like the sam- ples, you'll like Edgeworth wher- ever and when- ever you buy it, for it never changes in qual- ity. Write your name and ad- dress to Larus & Brother Com- pany, 10-I South 21st Street, Richmond, Va. Edgeworth is sold in various sizes to suit the needs and means of all purchasers. Both Edgeworth Plug Slice and Edgeworth Ready-Rubbed are packed in small, pocket- size packages, in handsome humidors hold- ing a pound, and also in several handy in- between sizes. We'll be grateful for the name and ad- dress of your tobacco dealer, too, if you care to add them. To Retail Tobacco Merchants: If your jobber cannot supply you with Edgeworth, Larus & Brother Company will gladly send you prepaid by parcel post a one- or two- dozen carton of any size of Edgeworth Plug Slice or Edgeworth Ready-Rubbed for the same price you would pay the jobber. POPULAR SCIENCE MONTHLY Canvas Strip Used as Campers’ Shoot-the-Chute ‘Tis is perhaps the cheapest, lightest, and most easily transported shoot-the- chute that the camper can make—simply a length of heavy canvas about 2 ft. wide provided with a grommet in each corner. One end is attached to a tree limb and the other end to two posts, or anchored to the bottom by means of heavy rocks. Adapting a Die to Thread Hard Rubber and Fiber N RADIO and other work it is difficult to cut clean threads with an ordinary die on rods of hard rubber, fiber, and similar materials. The crumbling of the threads can be overcome by modifying the die as shown in the illustration.* - First run a thread on a rod of brass or soft iron and then file three flats on it to make it nearly triangular in cross section. This is to serve temporarily as a tap. Plug the clear- ance holes in the die with the same material that is to be threaded and pie fitted with plugs use the improvised tap to clear out the die. This gives the die the appearance of a plain threaded hole, except for the difference in color be- tween the filling material and the steel. The clearance-hole plugs serve to support the threads as they are cut.—W. J. E. Drill Press Cheaply Built (Continued from page 82) should be machined down to fit into the ball bearing selected for this point. In order to machine this gear, it must be an- nealed. This may be done by heating to a cherry red and holding it at that tem- perature for a time, after which it is allowed to cool very slowly. It is likely that the gear will need to be bushed and a new key provided. The gear W carries a fixed key that allows the keyway in A to slide over it. The ball bearing that carries W is larger than the others and requires larger piece of tubing to mount it, @ is the same diameter as G’. It hag feat welded to it to support it on D, shaft A is made from a propeller and the shaft B from an axle shaft The ball bearings that support ty shaft B are mounted in steel blocks 99 These are turned in the lathe to fit into the pipes FF, which are split and Dro vided with bolts for clamping. The author purposely has refrained from going into minute detail wig reference to part sizes. A great deal of satisfaction comes to the builder of , piece of equipment of this nature jy knowing that he has incorporated some g his own ideas. It is a good plan t gather together every possible part tha might work into a projected machine ang see how they will lend themselves to th plan. The most intricate parts shoul receive first consideration. Each par used will be found to have a definite ip. fluence on other parts and on the desi of the entire machine. The chuck provided for this machine jy of the conventional design. It is drive by a 4-horsepower motor having a speed of 1800 revolutions a minute and carrying a 8-in. pulley. This gives a serviceable range of speeds. ouiintaiaaimneaat How to Repair a Clutch (Continued from page 98) garage or arbor press is the usual method, but the ingenious owner-driver can impr vise a jack, vise, or pry arrangement that will do the work. Where equipment is limited for hand ling this particular job, some mechanig use a couple of long studs threaded to fit the flywheel rim and thus by assembling the clutch in the flywheel they are ablet draw the cover plate down and at the same time compress the spring.—R.FK. Light Wire Holder Clamps Ink Bottle on Drafting Table LTHOUGH various ink-bottle holders are at the disposal of a draftsman, I have found the device illustrated to be especially satisfactory. It is made of & single piece of spring brass wire bent # shown. The loop passes over the neck of the bottle and rests snugly against the shoulder.—A. C. SELETSKY. ert © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 19. UD an plane. fore, iF previo is on Topo. : The clear ' 2 by | by 22 Each wood suppo in. as body ai Va DIA STIFI META

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eptember, i: slide it Carries W 1 Tequites y : it, ¢ is t has on D, a peller xle shaft, UPPOrt the blocks 00, > to fit ints it and Pro. S refrai letail with eat deal of uilder of , nature jy ted some gf 0d plan t © part that 1achine anj Ives to the arts should Each par definite ip. the design machine jg 't is driven ing a speed ad carrying serviceable utch al method, can impr ement that . for hand mechanic aded to fit assembling are able to nd at the r.—R.F.K. aps Ink ‘able = Z tle holders lraftsman, ated to be nade of & September, 1925 UILT for carrying many passengers, an aerial express cruiser is a giant air- plane. This toy model of one is, there- fore, larger than the three airplane models previously described in this series, but it js on the same scale and in correct proportion to them. : The body is whittled from a piece of clear white pine or other soft wood 34 by 2by17in. The upper wing is 4 by 2% by 22 in.; the lower, 14 by 2% by 16 in. Each of the two motors is whittled from a wooden block 14 by 1 by 2 in. and is supported by two strips 3/16 by 4 by 3 in. as shown. The distance between the body and the motor on each side is 3 in. wail 150 [o) COLOR WIRE Weoia(- BODY - BROWN TEF WINGS - YELLOW A WeTAL, {iT ] DOORS AND WINDOWS rs I TO BE PAINTED ON Fd t rien s WOOD a a 3,"tt’ LENGTH 18" THIN a4 Aert} HEIGHT 5 METAL WWOTOR| SPAN = 22", TAIL iii=4 | CHORD 22 27 H e 1 1 WOOD TT + ' vie x 2x3" a \ 4 : i } ys" 3" Side, top, and front views of the fourth in a series of realistic toy airplanes It will be noted that the two small strips that support each motor also brace the upper wing, and two similar strips are used to attach the center of the upper wing to the body. The landing-gear, tail members, and propeller, as in preceding models, are made of thin sheet metal. The wheels are 3/16 by 114 in. wooden disks. The next toy in this series will be a transatlantic air-liner.—D. W. C. Adjustable Float for Fishing Y BEING free to PAPE ; slice on the line, this adjustable float allows the fisherman to reel in his line com- pletely when through POPULAR SCIENCE MONTHLY 109 fishing. It is merely a large cork with a Y-in. hole through the center, bushed at each end with a Jarge glass bead. The fish- line runs through the beads. When you are ready to cast, simply push a small wire paper clip over the line at about the point at which you wish the float to re- main.—L. B. R. eltaeets Sliding float © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 1% Any bit stays tight in this chuck Here, at last, is an efficient bit-brace chuck. Slip into it any shape bit (round, square, any taper), and the bit is held in a vise-like grip. Saves time by centering bits accurately, and locking and releasing them instantly. Ball-bear- ings give chuck the easy action in your hand. With it you can do every kind of boring job within the scope of a bit-brace. “YANKEE” Ratchet Bit-Brace No. 2100 A touch on the easy-acting Ratchet Shifter gives you a powerful ratchet that works without needing a hand to prevent chuck from turning back. Ratchet is bronze-encased against dust and moisture. “Yankee” introduces for the first time hard rubber Brace handles. Won’t warp, shrink, bind or crack. A patented method prevents excessive play in sweep handle. Finished beautifully in keeping with its perfect mechanism. See it today in the “Yankee” Counter Demonstrator, at your dealer’s. Made in four sizes—8-, 10-, 12-, and 14-inch. Chuck holds rounds up to %-inch; 14-inch Brace holds up to 54-inch square. Dealers everywhere sell ‘“Yankee’’ Tools Try This Test Put Auger Bit into chuck of ‘‘Yankee’* Brace. Bore deep into tough wood. Then pull upward with all your strength. Bit not come out of chuck. “YANKEE” TOOLS Make Beller INechanics **Yankee”’ on the tool you buy means the utmost in quality, efficiency and durability Write for FREE ‘‘Yankee’’ Tool Book NORTH BROS. MFG. CO., Philadelphia, U.S.A,

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ee etgercarteestcrn seats hanear te

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{2 MONTHS 18 MONTHS 24.MONTHS ‘‘When I enrolled for LaSalle training in Higher Accountancy,’’ writes J. L. Trudell, a Michigan man, ‘‘l was doing the simplest kind of clerical work. I had had no previous bookkeeping experience. Before complet- ing half the course—within a period of about eight months—three promotions brought | me to be assistant to the Chief Accountant. Within another year I was given entire charge of accounting, over about thirty-five assistants. The first of the year I was pro- moted to be Director of Advertising, with present earnings nearly 200 per cent more than when I first enrolled. I am very grate- ful for LaSalle training.’’ Nothing surprising about Trudell’s advancement. During only six months’ time as many as 1,248 LaSalle members reported definite salary increases totalling $1,399,507, The average increase per man was 89%. “I have aclient for whom I make an audit regularly twice a year,” writes S, G. Gray, a Tennessee man. The fee I receive is $25 a day and expenses. client is a former employer of mine, and I worked for him at one time at $100 a month. I know of no investment that pays as large dividends as LaSalle training.” You Have the Same Good Opportunity Is it worth two cents and two minutes of your time to learn in detail of the opportunities that would be yours in the field of Accountancy? All this information, together with an outline of the steps by which you may quickly fit yourself to take advantage of such opportunities, is clearly set forth in LaSalle’s 64-page book, “Accountancy, the POPULAR SCIENCE MONTHLY

This | Profession that Pays,” a book of invaluable assist- | ance to the man who is seriously considering Ac- | countancy as a Career. | The coupon will bring it to you without the slight- | est obligation, and with it details of the LaSalle salary-doubling plan, also the inspiring testimony of men stil] in their twenties and early thirties who have broken away from the low-pay ranks and today are expert accountants—with incomes ranging from $8,000 to $10,000, $15,000, $20,000 a year. Your start toward a bigger salary is as near you as the point of your pencil. For the sake of a brighter future—ACT. LaSALLE EXTENSION UNIVERSITY The World’s Largest Business Training Institution Dept. 983-HR Chicago I would welcome details of your salary- ling plan, with copy of ‘‘Ac- countancy, the Profession that Pays,’’ also acopy of ‘Ten Years’ Promotion in One,’’ all without obligation. (C) Higher Accountancy Training for positions as Auditor, Comp- troller, Certified Public A ant, Cost A ant, etc, Other LaSalle Opportunities

Ie opens the way to success in every important field | LaSa of business. If more interested in one of the fields indicated low, ch ere:

CBusiness Management OPersonnel and Employ- GModern Salesmanship ment Management OTraffic Management OBanking and Finance ORailway Station Man- CO) Modern Business Corre- agement spondence and Practice OLaw—Degree of LL.B. OExpert Bookkeeping OCommercial Law Oc. P. A. Coaching Olndustrial M < ¢ OB English Modern Foremanship OCommercial Spanish and Production Methods OEffective Speaking Name 2 eae Reavent Position....................... ES Sar tere awe Sienna Adda

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In the same way level another joist near the center of the room, having first leveled one end with the end of the first. Intermediate joists then may be lined by spanning the first two with the straight-edge, as in Fig. 2. Unless the joists all are planed to straight-edges, or have equal amounts of crown, it is useless to attempt to obtain levels from the center of any joist. It is extremely important to bring ail joist ends into the same plane. To prevent canting of the floor joists, fit pieces of 2 by 10 in. stock between all bearing ends. They may be placed in a direct line or staggered (Fig. 2). Ifa span is 8 ft. or-more, a center course of herring-bone bridging is required. The length of each piece from the obtuse angle, or “short point” of one end to the acute angle or “‘long point’’ of the other is the hypotenuse of a right triangle with a base equal to the distance between the joists and the side 714 in., while the angle cut is, of course, an acute angle of that tri- angle. If the joists are spaced evenly, one piece should be a pattern for all. Strike a chalk line to guide by, and nail the bottom ends of the pieces as il- lustrated at the bottom of Fig. 2. Do not nail the upper ends at this stage. Nothing but vertically grained flooring should be used, and preferably the lengths should reach across all joists, eliminating

Fig. 4. Rough framing and ceiling joist lay- out showing the roof braces to be removed joints. If joints are necessary, make them on the joists, cutting with a fine-toothed | saw and beveling under slightly to insure a tight fit on top. Take care, if the floor- | ing is surfaced on the under side, not to | nail a board upside down. The right side, | as shown in Fig. 2, is farther from the tongue and groove than is the wrong side. | Also, the upper lips are longer than the lower, that the joints between boards may come tight on top. A board upside down F iting ae “my Unfinished Attic (Continued from page 79)

is evidenced by the surface being lowe than its mates, and its stubborn refusal to nail up closely to the first board, Lay the first board to a straight line nailing through from the face, as the par. tition plate covers it. Blind nail the fol. lowing boards, using eightpenny wire box nails, and working from one end ty the other. If firm tapping with the side of the hammer and subsequent nailing do

Fig. 5. The floor beams are laid temporarily across the ceiling joists to form a platform not force a board into place, use a scrap of flooring as a buffer, striking heavy blows with the hammer or a hand ax, All splinters on the tongue should be re- moved carefully. To avoid loose and creaking boards, drive the nails firmly home, and if this cannot be done without hammer marking, use a nail set for the last blow or two. Sometimes a hammer dent can be taken out by moistening the bruised spot, thus swelling the crushed fibers. The outer ends of the flooring need not be smoothly cut. ot When the:center of the room is reached, the joists then being brought into aline- ment, nail the upper ends of the bridg- ing. The flooring then may be completed. If it is desired to surface the floor, it may be scraped smooth at this time pro- vided it is covered immediately to prevent marring during later construction. The advantage in scraping it at this stage is the absence of walls, which makes it easier. to smooth the extreme margins. How to continue from this point will be told in the second article of the series in next month’s POPULAR SCIENCE MONTHLY,

Novel Violin Bridge SINCE adding a weight such as a mute to the bridge of a violin softens or deadens the tone, it occurred to me that removing weight would have the opposite effect. A violin bridge, therefore, was cut out as shown, leaving , it strong enough to sup- port the strings, but with no superfluous wood. All the edges were rounded Be to give it a neater ap-_ Violin bridge pearance and also to lessen the weight. One-third the original bridge was removed. The result was a noticeable increase and improvement in the tone.—J. H. DOWNIE.

© This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 19.

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nN refusal st board, ‘ight line, 8 the par. il the fo. nny wire 1e end to he side of ailing do stage is. it easier int will of the SCIENCE } a mute ftens or me that opposite re, was September, 1925 POPULAR SCIENCE MONTHLY 111 Home Workshop Chemistry Simple Formulas that Will Save Time and Money OW often have you wished for a H water-resisting cement that would join glass, metal, and wood, or a combina- tion of these substances, tightly and firmly aud would not give way under hard usage? Such a cement is described below. When fastened together by it, articles can be placed in water for months without any injurious effects. Aquariums can be cemented with it, and the glass sides will not require any outside support. It will hold glass by the edges alone and at the game time resist the action of the water. Broken glass or porcelain can be mended with it, metals can be joined together, and metal can be attached to wood. This is of special value in resetting tool handles. The cement must be prepared in either a porcelain dish or in a béaker that can be heated. Make only a small quantity at Pouring creosote into beaker (below) and adding shellac to hot creosote while _ stir- ring (at right) one time, for very little is required to do considerable work. Creosote and dry flake shellac are re- quired. Just pour enough creosote into the beaker to cover the bottom of the dish. Heat over a small flame such as an alcohol lamp and add the shellac gradually while stirring the mixture. Add enough shellac to the hot creosote to make a very thick, syrupy solution. Allow this to cool, when it should be so hard that it is difficult to make a deep impression in it with a fingernail. The adhesive power will be slightly greater by having the mix- ture still thicker and harder, but then it is slightly more difficult to work with. In order to use this cement the parts to be joined must be heated to a tempera- ture sufficient to melt the mixture. The cement is applied hot by means of the stirring rod used in mixing the chemicals. The hot cement can be applied to the parts to be mended, even if they are only slightly warm, but then the joints must be heated over an alcohol flame so that the cement runs freely and enters and spreads uniformly. The parts to be mended will not be tight unless the joints are heated sufficiently to melt the mix- ture. The thinnest film, if properly ap- plied, will hold as well or better than a thick blob of the cement that will not adhere to the mended parts. Correct Design Clean, Accurate Graduations Exact fit of Spindle in Frame Accurate Micrometer Screw Perfect Contact of Measuring Surfaces BROWN & SHARPE Quality The “Rex” gives you all these things In examining the ‘‘Rex,” you will first be im- pressed with the careful workmanship, the clean cut graduations, the polished thimble and barrel, the smooth, enameled frame. The ‘Rex’ is a High Quality Micrometer—only the price has been left moderate. Hold the “Rex” up to a strong light and turn its spindle down against the anvil. You will notice how accurately the measur- ing surfaces come together. Then there’s the mi- crometer screw—the heart of the micrometer—cut to a standard. —Remember, the “‘Rex’’ is a Brown & Sharpe Micrometer of the Brown & Sharpe Standard of Accuracy. “‘Rex’’ Micrometers which measure up to 24", and over 2000 other tools are listed in the Brown & Sharpe Small Tool Catalog No. 29. Copy gladly sent to you upon request. You'll notice areal super- tority in all Brown & Sharpe Tools when you look them over. © Brown & Sharpe Mfg. Co. Providence, R. I., U.S.A. BROWN & GHARPE TOOLS ‘“‘Standard of the Mechanical World’’ © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 19.

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Tana STE ET PNET RN AN AA TORR IR AE TR PR Pit 9 nm a, NNN TIER CTIA IE AEA ANRCR TN A NEWAE ENT AE 112 Books on Electricity The Electrician’s Wiring Manual By F. E. SENGSTOCK, E. E. Contains all the information needed for the proper installation of lighting and power systems in houses and other buildings. It completely covers inside elec- trical wiring and construction in accordance with the National Electrical Code. Pocket size—flexible binding 448 pp. Price $2.50 Construction of Small Al- ternating CurrentMotors By PROF. A. E. WATSON Brown University This book contains complete instructions for building small al- ternating current motors in several sizes. “ie designs will be found in harm v with those of the very best manufacturers and they can be worked out by the amateur for making useful instruments. Fully Illustrated. Price, $1.50 Experiments with 110- Volt Alternating Current By J. D. ADAMS Here at last is a book that devel- ops a practical working familiarity with the alternating current—the form in which electricity is used in every home. The author shows how this can be done in an inter- esting and inexpensive way. 256 pages, 135 illustrations. Price, postpaid, $1.75 How to Make Things Electrical This book gives directions for making hundreds of electrical appliances and devices for the home, the shop and the garage. The simple directions and many drawings make the work easy. 429 pp. Price, $1.50 postpaid POPULAR SCIENCE MONTHLY 250 Fourth Ave., New York City POPULAR SCIENCE MONTHLY Y SHOP work is made easier by a M few inexpensive machine acces- sories and tools and some simple shortcuts. Four examples are given ‘below, not so much because they are out of the ordinary as because they will suggest similar and perhaps better ex- pedients. Time is saved on shaper work by using a set of hold-downs made as shown in Fig. 1. On one side of a piece of angle iron, just double the length of the vise jaws, I planed an angle of about 1% deg. as indicated. The angle iron then was cut in half to make a pair of hold- downs. It is better to have the side next the vise jaws short- er than the other side. To aid in clamp- ing tapered work in the shaper vise, I prepared a_ swivel block to use on one side of the taper, using it in connec- tion with the hold- downs. The swivel blocks are made of cold rolled or ma- chinery steel. One block has a circular projection that fits into a corresponding seat in the opposing block. The blocks have a %- or 1-in. space between their inner parallel faces. The dimensions of the blocks and the hold-downs may be varied. One day I needed a few thumb-screws in a hurry and, as there was none in stock of the right size, decided. to make them. The method I followed was not only quick and cheap, but saved the time that the work would have been delayed while awaiting the arrival of purchased screws of the correct size. An ordinary washer and a fillister-head machine screw were used as shown in Fig. 2 to make each thumb- screw. The washer was cut in half and soldered into the slot; the projecting ears then were filed round. This made a thumb-screw of good appearance that served the purpose quite as well as a commercial thumb-screw. In the figure are shown variations of this idea to suit different styles of machine screws and bolts. WASHER CUT ON DOTTED LINES ce CENTER DRILL ” KNURLED HOLDER POINTED TOOL EO: Kinks that Make My Work Easier By E. C. Fellows HOLD-DOWN ANGLES SWIVEL BLOCKS CASTING FACED ON it ONE SIDE ; Hold-downs and a center drill holder; meth- ods of making thumb-screws and thin washers Figure 3 illustrates a tool that Saves much time in centering work in a lathe It is a holder for a combination drill ang countersink of the conventional king The holder is made from a piece of cold. rolled or machinery steel 11% jn, in diameter, with a hole drilled and reamed in both ends. The holes are made to accommodate two sizes of drills core. sponding to the sizes in general use, 4 setscrew is used to lock the drill in plac. In drilling the holes it is important that they should be in line with each other and true to size, The ends of the holes are chamfered slightly to fit the lathe center and the outside is knurled to provide a hand grip on the tool while it is in use. Turning and fin. ishing a thin disk or washer in a lathe js not always an easy task and some ma- chinists make a poor job of it or spoil a few before they tum out a good one When I have a job of this kind, I pro ceed as follows: If the disk is made of sheet steel or iron, which is the usual and by far the most economical way, I first face one side of Then I find a round casting of suitable diameter and chuck it in the lathe as seen in Fig. 4. Next, I face of one side and drill and tap a hole in the center for a bolt or capscrew. I then clamp the disk on the casting by means of a capscrew anda small washer. The two finished faces abut each other. By taking light cuts with a sharp pointed tool, I reduce the metal to the right thickness and then finish the outside diameter. If the inside diameter is to be finished to a specified size, the disk can be held to the casting with three small screws on the outside. Remove the central screw after tightening up the outside screws and proceed to turn the inside diameter. Re move the sharp edges with a file, and the piece is finished. By this method I have made washers 1/64 in. thick that were true and anes SOLDERED IN Go=m : i SD? a — — SS TAILSTOCK CENTER parallel in thickness. —— © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 19.

Page 101

‘Ptember, ly september, 1925 Siler hat sayey n a lathe . drill and mal kind, e of cold 4 in, in d reamed made to ills corre. il use. 4 | in place, tant tha ld be in ach other to size, of the hamfereq » fit the r and the nurled to 1and grip | while it and fin- in disk or a lathe is an easy ome ma- ke a poor r spoil a chey turn od one, ve a job d, I pro lows: If made of or iron, he usual the most way, I e side of [I find a ting of iameter it in the n in Fig. face off nd drill ole in the . bolt or I then disk on y means Ww anda ed faces cht cuts luce the nd then finished > held to rs on the ew after ws and er. Re and the washers ue and

—$$—

POPULAR SCIENCE MONTHLY 113

Romer Shop Mictiiodls | Old Bill Says— HE right man can make a good T job out of any job. Back gears should be used only when more power is required to pull a heavy cut, or when the speed must be re- duced to cut exceptionally hard or tough materials. One way to avoid getting a square deal is by not giving a square deal your- self. Before begin- ning to lay out a piece of work, it is necessary to have a definite idea of what the drawing means, a full knowledge of the operations through which Old Bill, machine- the work must shop foreman pass, and some idea of what is to be expected of the job when finished and returned to its shop. Keep thinking about the next move you are to make; learn to think ahead.

Use a handle on a file when filing in the lathe. When melting babbitt, stir in some rosin or oil. This will purify and thin the metal, and all foreign matter will come to the top. Initiative means doing the right thing at the right time without being told. Any machinist can become a master of his craft by constant application and study. Magazines, books, night schools, and correspondence schools all help.

Universal Test Indicator

CERTAIN shortcomings of the ordinary test indicator are met by the one il- lustrated above. The rod running through the shank of the tool can be adjusted to suit the work at hand and locked in position by a knurled screw. This is vital on difficult work where the center-punch mark to be indicated is far back from the front of the work. Since the indicator rod must be 18 in. from the point in some kinds of my work, it can be seen = the standard indicator could not be A detachable cone-shaped point is used to indicate a hole. It is attached to the rod with a screw. Collars, springs, and two Y-in. balls keep the indicating rod tightly in place against the ball seat.— Huco Lyunequist, Philadelphia, Pa.

The telephone door More people enter our homes and offices by telephone than in person. ‘Through the telephone door, traveling by wire, comes a stream of people from the outside world on social and business missions. Important agreements or appointments are made, yet the callers remain but a few seconds or minutes and with a “good-bye” are gone. We go out through our telephone doors constantly to ask or give information, buy or sell things, make personal calls and on dozens of other errands. None of the relations of life is more dependent upon co- operation and mutual consideration than these daily millions of telephone journeys. It is the telephone company’s part to fur- nish the means of calling and to place courteous and intelligent employees at the service of the public. Good service is then as- sured when there is a full measure of co-operation between users. Only by mutual care and consideration can everyone enjoy the full pleasures and benefits of calling. Telephone courtesy is for the good of all who use the telephone door. AMERICAN TELEPHONE AND TELEGRAPH COMPANY AND ASSOCIATED COMPANIES BELL SYSTEM One Policy, One System, Universal Service

© This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 19.

WoRLD's HANDIEST CALCULATOR an a POCKET SIZE Does work of large $100 machine BABY CALCULATOR} j and very simple to operate. pSHICAGOUS A | | ADDS sy

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Easily carried. Quickly attached to any SUBTRACTS 50 boat Grithoat tools). Drives boat any || ESRSRTESIGRSACT MULTIPLIES a no work, no bother. ‘ DIVIDES TOTAL COST Fast—Lizht—Powerful Easy to Carry Has 12 exclusive features, all Py Catalog Witte fenit teen -| Elto Outboard MotorCo. : Manufacturer’s Home Bldg. Dept, W Is GUARANTEED for 5 years. Made of steel. No upkeep. No re- pairs. Everybody who figures needs one. A SPEED MARVEL Positively the LOWEST PRICED 2 tical calculator on market, New J ADDITION im| Offer, price $2.50, id money order or Milwaukee, SUBTRACTION | Bay postman when machine is delivered. Wis. | | MULTIPLICATION upply limited. ORDER TODAY. = DIVISION Ss = » AGENTS WANTED «<The Motar that Starts with a Touch Baby Calculator Sales Co, , P. 0. Box 1118, Dept. 12, Chicago, Ill.

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at your finger be Know the facts in Electricity. They mean_more money and better position for you. Hawkins Guides tell you all you need to know about Electricity. Every ant electrical subject covered s0 you can understand it. Exsy to study and apply. A com- Dies, penetions working course, in 10 volumes. size; flexible covers. Order a set to-day to hook over. HAWKINS GUIDES 3500 PAGES 1 A VOLUME 4700 PICTURES 1 A MONTH These books tell you all about — Magnetism — Induction — Experiments — Dynamos — Electric Machinery — Motors — Armatures — Armature Windings — Installing of Dynamos — Electrical Instru- ment Testing—Practical Management of Dynamos and Motors -Vistribution Systems-Wiring-Wiring Diagrams —Sign Flashers—storage Batteries— Principles of Alter- nating Currents and Alternators—Alternating Current Motors—Transf ormers—Converters— Rectifiers—Alter- nating Current Systems—Circuit Breakers—Measuring Instruments—Switch Boards—Wiring—Power Stations —Installing —Telephone —Telegraph —Wireless—Bells— Lighting—Railways. Also many Modern Practical Appli- cations of Electricity and Ready Reference Index. SHIPPED TO YOU FREE Notacent to pay until you see the books. Noobligation to buy unless you aresatisfied. Send Coupon apeattieace od —and get this great help library and see if it is not wort $100 to you—pay $1.00 a month forten monthsor returnit. ? - THEO, AUDEL & CO. 6S W. 23rd St., N.Y. Please submit for examination Hawkins Electrical Guides (Price $1 each). Ship at once, pre- paid, the 10 numbers. If satisfactory, I agree to send you $1 within seven days and to further mail you $1 each month until paid. Employed by Resid Refer 9T34 Dyke’s Automobile Encyclopedia Entirely Rewritten, Rearranged and Illustrated. Greatly Enlarged; 1238 Pages, 4143 Illustrations. A Practical Book for Everybody The Repairman will find this book a ready reference and guide. The Auto Owner will know how to diagnose troubles and know when repairs are done right. The Student learns the funda mental principles, the key to a suc- cessful repairman. This Book Will] each You to Become An Expert Auto- mobile Repair- man, not only on testing, adjust- ing and repairing engines, carbure- tors, clutches, rear axles, differentials, tires, etc., but an Electrical Expert on ignition, gener- ators, starting mo- tors, storage bat- teries, etc. Diagnosing any trouble will be easy. Don’t wait—Order Now! Cloth $6.00—-Limp American Morocco $7.50 Postpaid Popular Science Monthly 250 Fourth Ave., New York City POPULAR SCIENCE MONTHLY eens SNopiMCONOUS! Special Lathe Boring Tool Has Running Adjustment ;LAsE of adjustment is the special feature of the lathe boring tool il- lustrated. It is not necessary to stop the work to withdraw the boring head so as to set the tool out from the bar. One end of the shank is tapered to fit the tailstock spindle. The other end is provided with a hub, which is about 14 in. off center. It is fitted with a correspond- ing sleeve, which is a snug fit. The bar X fests) UHHH SETSCREWS aa 5 TOO’ perenne tai) Ty ' \ ili ; 4 ii) SHANK Ala PLAN VIEW SV N CUTTER END WORK OF TOOL - ECCENTRICITY OF BAR AND SHANK Without withdrawing this boring bar from} the work, the tool may be set either in or out extending from the sleeve is of the con- ventional type and has a cutting tool held with a setscrew. Two setscrews pass through the sleeve and bear against inclined seats in the hub. With a socket wrench on each setscrew, it is possible to release one screw and tighten the other. This rotates the toolbar and, as the hub is eccentric, movement in one direction places the cutting edge farther out from the center within the 1-in. limit.—G. A. L. Foot Lever Feed for Rapid Work on Small Drill Press ANUFAC- TURING work on high-speed drilling machines often can be handled more quickly if a foot- ° lever feed is at- tached to the spindle. The gen- eral arrangement of such a pedal is illustrated. The pedal arm is attached to the base of the machine by means of the clevis marked 1, made from 14 by 114-in. iron and fastened with countersunk head screws. The pedal itself is bent in the form of an S about 8 or 10 in. from the ful- crum. Itis connected with the drill spindle by means of a rod of suitanle length with ball or knuckle joints at each end. The handle used for hand feeding should be set horizontally and fitted with a spring to raise it when pressure on the pedal is released.—F. J. WILHELM. Cabinet _ Shop Special No.7 Make a real shop in your basement! This handy Parks woodworker is complete shop equipment in itself. With it you can do all sorts of cabinet work. Make toys, furniture, radio cabinets—anything. Built for close, accurate work, vet small enough to fit in a corner of your basement. Operates from light socket. Has motor, rip and cut- off circular saw. jointer and bandsaw. Add lathe and sharer at slight extra cost. A real machine ideal for home use. Send for circular. The Parks Ball Bearing Machine Co, 1547 Knowlton St., Cincinnati, Ohio September, 1995 Canadian Factorv: 2 Notre Dame Fast. Montreal. Canada @ This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 19. Geared 80 to 1 Adaptable to coarse or fine tuning, the infinite precision of the Accura- tune brings in all sta- tions within the scope of your set clearly, strongly, and with little effort on your part. Easily substituted in a few minutes for ordi- nary dials without al- teration of your set. An essential accessory. Write for descriptive folder MYDAR RADIO CO. 15 CAMPBELL STREET NEWARK, N.J. © Septen

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Op rit! plete u Can toys, Built gh to Tates | cut- Add Send Chasing a Difficult Thread (Continued from page 84) in diameter that had come in to have some missing teeth replaced. He nodded ap- proval when he saw l-in. studs being screwed in with a 2-ft. pipe-wrench. “T am glad to see that you are getting them in tight enough to stay,” he said. Laten, the machinist, kept on with his work. Old Bill wandered on. When he came back afew minutes later, the last stud had been screwed in and sawed off. The machinist had begun to chip them. As Old Bill approached he was chalking the ends of the studs and, with dividers set from good teeth, spacing off the ends of the teeth, always spacing from a good tooth. “That is the best way to make them accurate, Bob,’’ Old Bill said. ‘Get a thin piece of sheet iron and make a tem- plate so that you can get the curves of the teeth about right. Hold the sheet on the side of some of the good teeth and scribe the outline so that you can cut it to the shape of the teeth. There is one other thing that you can do: “Clean out several of the good teeth and cast a babbitt imprint of them that you can use to try on your studs to be sure there are no high spots to pound every time the wheel goes over. Clamp a board on each side of the teeth and fill up about three teeth with babbitt, and have a web to connect these teeth. Then you can use these babkitt teeth to ‘spot in’ the new teeth.” “T had been wondering how I was going to get them just right,’’ Laten said. “You will not be able to get them just right,”’ Old Bill replied; ‘“‘but you can get them pretty nearly so by using all three of these methods.”’ OL” BILL could tell by the group gathered about the big radial that the thread-cutting job was about to com- ceedings. “T thought I would bore the hole round with a flat tool before cutting the thread,” the machinist explained. “That is a good idea; it will give you a better chance to set your threading tool.” The drill had a tapping attachment, so the cutting of the thread was not so hard asit might seem. The thread tool was set for a light cut. It was run down slowly the first time. Old Bill held out a hand. “Now, in bringing it up again, be care- ful that you do not spoil the thread you have started,” he said. “Do not let the screw have to push up the whole weight of the spindle, but help it out with the feed lever.’’ About four cuts down produced a sat- isfactory thread. Thé welder’s helper had already brought in the seat that had been built up, and one of the machinists had taken it to a lathe to turn it off and chase the new thread. Old Bill felt the depression that some- times comes from a hard day’s plugging about the shop rise from his shoulders. He knew that the pump would be de- livered on time! turned to the magazine. mence. He went over to watch the pro- | A smile illumined his face as he re- | POPULAR SCIENCE MONTHLY The fellow who tinkers around the house says the handiest tool in his whole kit is a good husky, keen-knifed pair of Klein’s eight inch side cutting pliers. Your hardware retailer will tell you that they are stand- ard with the professional mechanic. & Sons Mathias Chicago lI] USA Back of Each Instrument ee et The assurance of reliable performance, which you have always felt when buying an ALL-AMERICAN Transformer, is now increased by a knowledge that it is the product of one of the largest and most completely equipped factories in America devoted exclusively to radio products. The RADIO KEY BOOK—new edition—is a practical handbook for all who wish to enjoy modern radio at its best. Send 10 cents—coin or stamps—for the KEY BOOK. ALL-AMERICAN RADIO CORPORATION . E. N. Rauland, President 4215 Belmont Avenue Chicago ALL-AMERICAN |Largest Selling Transformers in the World © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 19.

Page 104

POPULAR SCIENCE MONTHLY September, 1935 9"x3’ - - $241.00 11"x4’ - - 288.00 13"x6’ - - 366.00 16" x8’ - - 498.00 Easy payments if desired. Write for Catalog No. 84 817 E, Madison St., Challenge the World in Lathe Value Quantity Production reduces our costs. We pass the saving on to you. Prices Quick Change Gear Lathes SOUTH BEND LATHE WORKS South Bend, Ind. 15" x6' Quick Change Gear Lathe, Price $431.00 NEW VEST POCKET ADDING MACHINE pull of the ket full of pencil stu —? do your figuring. Carry a Ve-Po-Ad. 9 Sendno money. 10 Days’ Trial Sontmme and erg and we will send machine y postman on delivery $2.95. +" rove it does all we claim. Your if not perfectly satisfied.Don’t ied by cheap imitations. er your Ve-Po-Ad now from this ee Bollable Adding Machine corp. Dept. °C The Finger Print on the Gun -~ Two shets rang out in the dere ness with but a single report. One found its mark inthe heart of an in- nocentman. police. But behind ty the m *s revoly=- er with the telltale finger print clearly impressed on the smooth, bluedsteel. Almostevery pa tells of the exploits = the Finger expert, the master detective. don’t you— Bea Finger Print Expert More men are needed every day. But only | maponend men are wanted. Wewill train you at home in spare time, as we have trained many of Amorlen's greatest experts. Big Money to Experts P's, :s!s; Rich rewards offered for ‘‘wanted’’ man. Unlimited ee for aprofessional business of your own. Write at once. al Offer Now Ge. ‘tn de. Also our Free book on Finger Prints, full of —— “stories of crime mysteries solved by our grad- uates. Professional Outfit and course in Secret Ser- vice Intelligence included without extra charge if youenroll now. Write today. University of Applied Scien 1920 Sunnyside Ave., Dept. 13-66, itis Earn'i90 1 WEARING THESE ‘HUTCHINS PANTS cs ogg nw prices and wonderful quality make Hutchins made-to-measure trousers sure fire sellers. You merely take orders, we deliver. Guaranteed finest quality, beautiful materials. Men eager to buy at amazing low prices—$5.95, two pairs for $11. Your big profit in advance. iJ No Experience Required Even inexperienced men earn £90, $100 and more a week taling orders. Get your tailored pants FREE and cash in big on this opportunity. SEND NO MONEY 220"'30.27025) dress. Beautiful samples sent you FREE. But act at once. Do not delay. Start right out making big money. Address GUTCHINS PANTS CO., 59 East Fifth St., Cincinnati, Ohie Course for men of am- soa _ limited. time. Electrical 000 men trained. Condensed course it 4 a Practical Elec- ing the trical eo - Engineering % %- related subjects of ge age and Mechanical Drawing taught by experts. tudents construct motors, install wiring, test electrical machinery. Course Complete. In One Year Prepare for your profession in the mos interesting ¢ city tes = world. Established BLISS ELECTRICAL SCHOOL 209 Takom. Ave . W°shington. D.C. includ- STUDY AT HOME Become a la bige win th liclife. Be ind rtunities now ponmneaiene are headed by mcn wi Law trained men earn i training. $5,000 to $10,000 tome ga ss ae Boge Ee Socata in eves — ‘We farnis! fourteen-volume ww cost, le 108- “Law Guide” a **"Bvidence’ lor them N Now, LaSalle Extension University, De $83-L The World’s Largest Business , Chicago sion Tee of ~ most profitable fields of Commercial Art. Positions always open. Ex- perts earn $5000 year. Prac- tical and easily mastered course. Personal instructions. No special abi'ity required. Write at once for full articulars. School of Commercial Illustrating 586 Century Building, Indianapolis, Ind. Saw. tilts full 45 degrees. ws 6” stock. P. Motor. Portable. w.B. a4, E. Boice, It’s Easy to Build Things! You can build practically every job of woodwork quicker, easier and better with Boice-Crane Bench Machines New Improved Band Handisaws made in 3 14’ Wheels. Table sizes. stock. deep x 54” wide. Either machine driven by 4 to 4 H. Attach to light socket. Unsurpassed values and prices. Write today for descriptive catalog of Bench Saws, Drills, Jointers, Band Saws and the oe E-Z-. Pay Plan. Dept. P. ‘orld's Largest Makers of Small Bench Machines.’’ 8” saw cuts 244” Dadoes 1%” _™ S. 9-A, Toledo, Ohio. Roller for cclatastes Railway Air-Brake Expander Rings T°? RECLAIM railway air-brake ex. pander rings, I made the roller illyg. trated. With it I found that I could re roll the rings for less than half what they cost new. eight hours. The rings, which are used in the brake cylinder of the railway air-brake equip- ment to hold the packing leather againg It is possible to roll 700 in free | Iperere oat The rolls have grooves for rings from 8 to 18 in. in diameter. One wide-faced gear was sawed in half to make the two operating gears the walls of the cylinder when brakes are applied, become unserviceable by getting out of round. As they are very low priced, any method of truing them up must allow all the work to be done in one operation. Finally I hit upon the idea of rolling them, but the rolls on the market were too soft to stand up. I had some wide struc- tural steel plates forged to shape in the blacksmith shop and machined to size. Five grooves were provided in each of the tool-steel forming rolls. The idler roll is blank.—ARCHIE SKINNER, Chicago, IIl. Special Tool Cuts Awkward Holes in Furnace Walls N ORDER to install a heat- ing coil in an old hot-air fur- nace, I had to cut two circular holes in the furnace wall as well as in the outside shell, 6 in. away. It was out.of the ques- tion to do a neat job with a chisel, so I forged a special drill from an 8-in. piece of 34-in. tool steel. After shaping up this | steel as illustrated, I drilled a hole into which to insert the centering | point. This I had soft soldered in place after the drill had been hardened. As the drill was turned on this centering point, the cutting edge, which was ground like a small chisel, made a clean circular hole very quickly—HucGu L. CorrMaN, Denver, Colo. ————_—____— © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 19. we COA

Page 105

— “il :

kes are getting priced, st allow sration. rolling rere too 2 struc- in the tO size. ‘ach of ler roll zo, Il. ard S

ntering | place d. As atering zround ircular ‘FMAN,

POPULAR SCIENCE MONTHLY

PF Shop Metihodls|

Unusual Ways of Reclaiming Spoiled Machine-Shop Work By Charles Kugler

garage work in machine-shops runs into millions of dollars annually, yet only a small percentage of it is reclaimed. Few are the shops that do not have to contend with this problem. The me- chanic who never spoiled a job is rare indeed. Between the planning and the completion of a job, no matter how skilled the individual worker may be, there is always a chance for misunderstanding and errors. Doctoring a spoiled job is not always practicable nor even advisable, even in cases where there is no hazard involved other than the reputation of the shop. WOOD i

BRASS TUBE THIS END GRIPPED IN HOLD THIS END CHUCK OF SPEED LATHE BY HAND = \

= 4 io 1) Tim | me Method of shrinking a steel bushing, expanding a brass tube, and re-turning small brass rods

At the same time, a great deal of incorrect work could be rectified so that it would function in every way as well as if made properly in the first place. Every effort to eliminate waste in this direction is worthy of consideration. If the error is the result of wrong specifications or

(Continued on page 118)

SARGENT

SARGENT PLANES will help you —just as they have helped thou- sands of carpenters in shops and out on building operations every- where—to get the best from your work. They are tools of the master craftsman, but so moder- ate in cost that they should be in every home and school work- shop. They will soon pay for themselves in improved work and a saving in time. They are so strongly built of finest ma- terials that you may never have to replace them. 50 Water Street

PLANES

Give your work | the professional touch SARGENT & COMPANY, Manufacturers Sargent Steel Block Plane No. 5206 Sargent Auto-Set Bench Plane No. 714

The Sargent Auto-Set Bench Plane has a feature found in no other plane. The cutter may be removed, sharpened and replaced without changing original ad- justment. It is really a great time and labor saver. The Sargent Steel Block Plane is one of the most compact and capable small planes on the market. It is great for end work and the smaller jobs. Most good hardware stores sell them. We will send you the Book of Sargent Planes upon request.

New Haven, Conn.

I OFFER YOU $200 A WEEK °*2¢ . We want men and women in eve community to demonstrate and take orders for Comer All-Weather Top Coats and Rain Coats. New offer enables you to earn $200 a week and a Chevrolet Coach. Nocol- lecting or delivering. No ex- perience need Mail the coupon now for full details. The Comer Mfg. Co., Dept. O-413, Dayton, O. Ero cudere eee wow eee me's eee TRG FRG MOUs «oo ccicuctccevacs The Comer Mfg. Co., Dept. 0-413. Dayton, O. Without obligating me in any way please tell me how I can make $200 a week and get a Chevrolet Coach.

Priut or write plainly *

@ This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 19.

cel Sg RK PLUG Ay Visible Flash Just Out— Amazing eg oo Beacon Lite Spark i RY —= see the flash of each explosion ~ = the cylinders. Tells which are firing ri; imp t in spark jugs { SSisince gas engi ‘one ~~ derful gas savers. Agents coining money. EK Easy to make with new sure-fire plans. Sells on < 5 adh to. every autoowner. Phillips, Ont., ——— ies ‘Sold 2 dozen today, 3 dozen yes- ——ees terday. Rush 10 dozen.” Write for s su cial Free Demonstrator Offer and F WS deal to introduce a wonder ma your territory. CENTRAL F PETROLEUM COMPANY 685 Century Bui Cleveland, Ohie

Page 106

POPULAR SCIENCE MONTHLY

Reclaiming Spoiled Work (Continued from page 117) incorrect dimensions on a drawing fy. nished by a customer, it may be permis. sible to suggest a means of saving the joh in the customer’s interest. In many cases the reclaiming of a piece of work calls for considerable study anq ingenuity and in any event the cost must not be greater than that of producing q new piece, unless time is the most jm. portant consideration. The following examples demonstrate what can be done to save work that at first glance seemed to be irredeemable. Six bushings like the one shown were bored and reamed on a turret lathe. The axis of the turret was not in line with the lathe so that the reamer, which was not in a floating holder, made the hole .010 in, over size. The general opinion was that nothing could be done to save the bushings, One of the machinists said that he would like to tackle the job, as it was something he had been up against before, so the fore- ) man let him have a try at it. The Two tools that ought to be in every man’s tool chest, | jushings were placed ina gas furnaceanl * Vaughan’s Vanadium Steel Hammer and a Drop Forged Un- | heated to about 1500 deg. A hot bushing breakable Plane. They’re two sturdy tools that will give years rag wae tg in : ome a : : wo wooden blocks and two sheets of of service. Your hardware dealer has a full line. tition ahakeerm. ‘heekin al tion was quenched in water. The first

VAUGHAN & BUSHNELL bushing quenched shrunk about .015 in. MANUFACTURING COMPANY in the hole. In the others a decrease of (Hakers of Fime Toots from .012 to .015 in. was obtained. This 2114 Carroll Ave ~ + Chicago, IIL U.S.A. was sufficient to allow the holes to be finished with a hand reamer, after which the bushings were turned and faced. The secret of this simple trick is to prevent RAISE YOUR PAY the water from coming in contact with the hole. \ \ ITH THESE B OOKS i ANOTHER instance I once employed a simple means to save a lot of pieces made from brass tubing. The error in

These books will give you an entire course this case consisted of cutting the thread under size, the result of the mechanic's of instruction in your trade in one volume. having been given a wrong gage to work They will start you on the road to big pay. by. As the inside diameter was not im- portant, it was apparent that if the tube could be expanded about 1/32 in., the om. Electrical Books . ‘ nenteqnnte Books thread might be recut. I turned a Telephony, Including Automatic Switching, utomobile Starting, Lighting and ee by Smith.....450 pp. Leatherette $2.50 Ignition, by Manly........ 700 pp. $3.00 machine steel plug of the shape shown. Practical Applied Electricity Sak aes 2 Brookes’ Automobile Handbook . 4 nee Bae = abe seer: % oy man of a large screw-machine department uilder’s Architectural Drawing..... . andbook for Millwrights..... ot A - - ee IIIS. 55 clip ny 5 >> 0,05 0 6.0 <inje'ev 3ie'e' $1.50 Machine Shop Practice......... Cloth $2.00 out of possibly serious trouble. Incl Practical Bungalows..............- $1.00 Mechanical Drawing and Machine dentally, this is an example of work that Roof Framing, by Van Gasbeek...... $1.50 eS ee eee Cloth $2.00 was saved with small chance of embar- rassment to any one, as there was no H E K ee sailed sacrifice in the quality of the finished § POPULAR SCIENCE MONTHLY pieces. § Gentlemen: : . : ob I had to reclaim a lot Check the book or books you want and | Please send me the books I have checked Another J 7 - lend 1/16 mail with your remittance. We will send the 4 above, for which I enclose my remittance of of brass rods turned on the small end 1/. books you order on the understanding that | $....I am ordering these books on the basis that in. too short. It should have been 3% in. if they do not prove satisfactory to you in J if I am not satisfied my money will be returned. every respect we will refund your remittance. J

instead of 5/16 in. as shown on the pre-

PEE Ricans usps ar ees ONE aes as aici ceding page. The error was not dis- Popular Science Monthly =; appress......... 0. ooo oo co cccccececeeceecees covered until the rods were assembled into 250 Fourth Avenue - ae tools and ready to ship.

(Continued on page 119)

© This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 19.

em awe

Page 107

ving fur. > permis. ig the job of a Diece udy and ost must ducing g nost im- following be done eemed to WN Were he. The With the as not in 010 in, was that ushings, he would mething the fore- it. The nace and bushing between heets of ‘ombina- The first 015 in, rease of 1. This Ss to be r which ed. The prevent ct. with nployed f pieces 2rror in - thread chanic’s to work not im- he tube n., the rned a shown. is was qual] to ty was outside uld be proper oy the 1e fore- rtment Inci- k that 2mbar- vas no nished s a lot d 1/16 3% in. 2 pre- t dis- d into Small Brushes for Shop Use Made Quickly and Cheaply OR years we have used emergency F prushes made as shown. There are hundreds of times when a mechanic needs a brush for a little job, as for putting a finish on @ neglected spot, gluing, shellack- ing a gasket, and the like. It takes time to hunt up 2 bristle bah and then (TTTry 2, perhaps the brush i] CANVAS js too large or needs cleaning. POPULAR SCIENCE MONTHLY Just take a strip of old awning cloth, ravel it out until the threads are long enough to make a suitable brush, and wrap N the cloth three Or ‘Three styles of brushes four times around on a strip of veneer from a berry box or a small twig or stick. After use the brush is thrown away. These simple little brushes have saved me many a dollar, so that I make up a batch at a time and keep them on hand for our automobile mechanics.—JOHN R. DopcE, Normal, IIl. Undercutting Commutator Mica Micé between the segments of a motor commutator can be cut down to a uniform depth with the tool illustrated. This is simply a saw blade fixed in a hard- wood block, which is made with two guiding edges on one face so as to fit the commutator snugly. A transverse bolt through the block clamps the saw in its slot. The saw is ad- justed to pro- trude just far enough to cut grooves of the desired depth and the block guides it so as to follow each groove exactly. Wooden guide for saw —G. A. LUERS. CLAMPING * BOLT Reclaiming Spoiled Work (Continued from page 118) I made a form-turning tool as shown, which was used in a speed lathe. The tool was placed in the chuck of the lathe and the rods were inserted into it by hand, and turned back therequired1/16in. As the over-all length was not important, a decrease of 1/16 in. in the length in i way affected the quality of the tool. To make the forming tool I first turned up a flat drill or cannon drill as iJlustrated. The dimensions of this drill corresponded to the finished dimensions of the piece. This was given the proper clearance for cutting and then hardened and tempered. It was used in the ordinary way to form the corresponding shape in the forming tool. hargeit while you sleep: Last thing at night—concert over—time to lock up. Radio battery low? Just clip on the Tun- gar, and plug it in. Or if you connect up the Tun- rs) gar permanently, just throw a switch. Charge the battery while you sleep. The Tungar is simple — makes no disturbing noise. And the low cost of Tungar recharging cuts battery upkeep to next to nothing. It means top notch performance—clear, full-volumed ree ception—all the time! uN The Tungar is a G-E prod- uct developed in the great Research Laboratories of General Electric. PAT. OFF. The new Tungar charges radio A” and B” batteries, and auto batteries. Two ampere size (East of the Rockies) . . . $18.00 Tungar—a registered trademark—is found only 60 cycles— 110 volts on the genuine. Look for it on the name plate. Merchandise Division General Electric Company, Bridgeport, Conn. GENERAL ELECTRIC © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 19. Made $7000 inOne Year’? Gx Sworn Statement by Frank DePries \\ He further states that he has made $900 in one month’s time, $500 in 4 \. \\ a single day, individual sales of 180, 114 and 105 machines at various a times. Mr. DePries has been with our company 8 years. Smith PS sees x oad of Minn. reports for one week — 43 hours, 44 calls, 28 sales, and : iY $166.20 profit. Robey, W. Va., quit a job at $175 a month and : now makes $500 a month with us. AGENTS WANTED Gy\ We need more men like these, because the demand for our Super Fyr-Fyteris \\ growing by leaps and bounds, Sells to garages, stores, factories, schools, homes, hotels, auto owners. Approved by the Underwriters. If you are willing to work and ambitious to make some real money, get our plan. You need no experience. as we train you without cost for the work. No great capital required. Good territory going fast. Better write us at once. THE FYR-FYTER MPANY 863 Fyr-Fyter Bldg., sais Dayton, Ohio

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POPULAR SCIENCE MONTHLY

place needed. cess, goods. gation invited. apply.

shercuettited seme

WANTED Men to manufactiire Metal Toys chance to start your own well-paying business producing such big sellers as Toys, Novelties, Ash Trays, Book-blocks, Souvenirs, Advertising Specialties, Paper Weights, etc. furnish forms with complete outfit for speedy production. Absolutely no experience or tools necessary; no Small investment puts you on road to suc- Demand exceeds supply and we assist and co-operate with our manufacturers in selling their products. you in touch with the buyers and assure an outlet for your Strictly a business proposition and thorough investi- A splendid“ opportunity for an enormous and profitable business for ambitious men. Catalog and information mailed on request. nena Cast Products Co., 1696 Boston Road, New York and Novelties. Good We special We put No others need

—Writes Peter Werner, Ill. Sell Madison “Better- Made” Shirts for Large Manufacturer Direct to wearer. No capital or experience needed. Many earn $100.00 weekly and bonus. Write for Free Samples MADISON SHIRT M’FRS, 505 Broadway, New York Only oe sii emonth fora few months easy toownthefamous © etandard TTE a |

Equipped with celebrated Troubleproot WICO Magneto. Simplest and cheapest to op- erate. New device makes gtertios eas: Pe Om au: rplus wer, Sizes 2to25 Sp atletpies. FREE BiG REW NINETY. DAYS" FRE An RIAL. ENGINE BOOK Write today for ny new illustrated engine book—sent absolutely Free. No obligationto you. WITTE ENGINE WOR KS 2228 Witte Building, - - - KANSAS CITY, MO. 2228 Empire Building, - « PirresunaH, PA.

oo CARTRIDGE PISTOL tection against Durglars, 2 Tramps, & Doge PRICES Well made and ef- fective; modelled on latest type of Revolver; —e *arance alone is th to scareaburglar, Whenloatiod it may beas mee = : real revo + ; : ‘ ver without danger to life. It t it d gal. oun < Carir: dges Shtsinable everywers. rior quai stpaid Blank “Cartridges, by express, 5Oc per f00. “PRINTED | STATIONERY $400 200 SHEETS, 100 ENVELOPES Printed with your own name and address (4 lines or less) in rich dark blue ink. Fine texture Hammermill Bond paver, smooth and beautiful. Sheet size 6x7, extra heavy envelope tomatch. Shipped in attractive box, postpaid. nver West add 10 per cent. emit with order, money refunded if not fully satisfied. member, there is only one **Ritemor’’, known everywhere and preferred by thousands. Order now. RITEMOR STATIONERY CO. 212 N. Alabama St. INDIANAPOLIS, IND.

PATENTS } BOOKL aia ng 4 + PROMPTNESS. F SSURED T RESULTS Send drawing or model for one and report as to patentability WATSON E. COLEMAN, Patent Lawyer 644 G Street N. W., Washington, D. C. Will Wear Shis Suit? Show it to your friends and neighbors as a sam = of our fine quality, hand-tailored All-Wootl Suits, , guaranteed $40 valuesat amazing lowprice } of $23.50, take their orders, keep handsome profit for your- self and send orders to us. #)| Agents Making i) BIG MONEY $3.00 to $5.00 an hour in spare ull Sime, $75 We et — for ime. Wesupply handsome Swatch Line Outfit, large size samples and all latest stylesin elegant Leather Case. Positively finest selling outfit ever furnished salesmen. Write 4 for yours at once, pick out your suit and get started i making the Big Moneyright away. Address Dept. 153. 3 848 W. Adams Street Chicago Write name and address below and mail at once.

' Div Lich with bbeetoebsoeesve6onwsseébeesvenee Se RP. ods Box DAs pUudibeeuebhensscccns sess DA as si owe e

IONS: INVENTIONS ces ON A CASH OR ROYALTY BASIS

‘In Business 25 Years Complete Facilities-References. Urie ADAM FISHER MFG. Co. FISHER MFG. CO. 183-D Enright Av. Sr. Lous. Me.

i) RADIO Storage “B” Battery 32Gehs Lasts Indefinitely—Pays for Itself Economy and performance unheard of before. Recharged Approved Fang listed as Standard by at a 5 negligi gible met, dio Authorities, including boratories, Pop se iT net, Standards, Be dto News Te. "i efex Inc., and other im porrant institutions. ipped with Solid Rubber ‘Case, an _insur- med inst acid and oy Heavy, plates. Order yours t SEND NO MONEY ear oped pomber of Ss agg od da order is received. Extra Offer: 4 battcries in series (96 volts), $12.7 7b. . Sper cent discount fot _ heavy glass jars. caah akin order. Mall your order mowl” ith ord e WORLD BATTERY COMPANY 12 19 So. Wabash Ave., Dept, 80 Chicago, on Pe ers of the Famous World Radio ‘*A’’ e a vec “G-volt, 109 Amp. $11.25; 120 ‘Amp. $18. rs 26; 140.Am U equipped with Solid Rubber World = S TORAGE BATTER! ES

© This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 19. September, 19%

| the cutter in any angular position desired.

Tool-Holders ond Toolbits ots Planing, Shaping, and Slotting F(ORGED tools for slotting and for cyt. ting keyways in holes often may be re. placed profitably by the type of tools Ulustrated. These tools are more efficient than the forged tool and at the same time considerably cheaper, since only the actual cutter is made of high-priced alloy steel. Cutters are readily made up jp stock and may be ground systematically and accurately by the tool grinder. Cutters of various forms for unusual places may be provided, such as on the

‘srooweirs SS as SHANKS FOR USE WITH SMALLER TOOL-HOLDER GF SAME TYPE : Tool-holder, toclbar and toolbits. The white arrow points to a roughing tool ready for use planer job illustrated, where a broad-nose tool 1 in. wide is used for finishing the left side of the rectangular slot in the cast- ing. A roughing-out tool is shown gripped in the holder, and the broad-nose finisher is lying on top of the casting to the left of the finished vertical wall of the slot. The round shank permits the tool-set- ting to be corrected and allows the use of Another feature is that the shanks or special round toolbars may be made extra long to suit varying lengths and conditions of work.—O. S. MARSHALL.

Emergency Repair for Pipe Line

BROKEN water, gas, air, ANGLE or steam pipe may be VALVE repaired temporarily by the use of a clamp made as shown from an angle valve, twe nipples, two elbows, and a short length of pipe. The pipe is a loose fit, so that turning the valve forces it against the fiber or other packing material used over the hole. These parts later can be returned to stock.—F. N. C. anus » Se » a) PIPE FITTINGS

Page 109

mber, 1% ——___

ts for tting for cut- xy be re. of tools efficient ime time nly the ed alloy e up in natically r, unusual S on the

OL-HOLDER

e white for use oad=nose hing the the cast- . gripped » finisher the left e slot. tool-set- ne use of desired. 1anks or ide extra ynditions e Line \NGLE IALVE YY SWIVEL SLEEVE YY PIPE FITTINGS ee - packing ese parts F. N.C.

September, 1925

The Power in Your Eyes (Continued from page 25) of mica, containing no wire, but lined on the inside and outside by strips of lead or aluminum foil. This made a type of con- denser, and more favorable results were obtained. Then he submerged the cylin- der in a glass vessel containing paraffin oil, so as to do away with any radiant heat effect, and even under these condi- tions the cylinder moved when the gaze was directed steadily at it. Mr. Beall says that he never “learned” to train wild animals; that he developed a natural ability. Doctor Russ’ experi- ments make it seem highly probable that this natural ability is in reality the pos- session of an exceptional amount of electric eye power. They may serve to explain also the marvelous power exerted over other men by the glance of great leaders such as Napoleon, and the de- moralizing effect on his ring opponents cf the famed ‘“‘hypnotic eye” of John L. Sullivan. Later experiments made by Doctor Russ have shown that there is a great difference in the intensity of the eye power of various individuals. The average glance at the wire coil produced a move- ment of 15 degrees. On the other hand. a brilliant actress, a woman of extraordi- nary personality and charm, was able to turn the indicator 60 degrees—a sixth of a complete circle. A famous flying man, an “ace” in the World War, did as well. [N MY talk with Mr. Beall he remarked that if ever dangerous animals are al- lowed to realize their superior strength, the trainer is lost. Men with 25 or 30 years of experience as trainers have been killed by animals they had worked with for years. Why? Doctor Russ’ experiments again furnish a _ possible answer. The gaze of a man who had been warned by his oculist that a cataract was forming on one of his eyes was able to move the indicator only a few degrees. Another man, under 30 but in the early stage of palsy of the spinal nerves, could make no more than a trivial im- pression on the instrument. In view of these experiments, is it not quite possible that the sudden disasters that sometimes end the careers of ex- perienced animal trainers are caused by some physical decline that results in a lessening of the electric power of the human eye? That actual though invisible rays of electricity shoot out from our eyes, exert- ing influence over men and beasts in pro- portion to their strength, is a startling conclusion. Perhaps the “electric eye” Is not a thoroughly proved fact, but Doctor Russ’ experiments, so carefully performed and so conscientiously checked, take it out of the field of superstitious fancy and into the domain of scientific research. This electric quality of . the human gaze, if actual and understood, might be made to serve very useful ends im many fields of human endeavor. For more definite conclusions about it we must await the results of the advanced Tesearch work of Doctor Russ and other scientists. a

POPULAR SCIENCE MONTHLY 121 Build this phenomenal new radio in 45 minutes

The Erla Factory - Bilt —as you receive it. revolutionary Circloid-Five Kit Price $49.50

© This new type kit is factory assembled. Ready cut, flexi- ble, solderless leads make it ridiculously easy to wire. Amazing new inductance principle brings results hardly thought possible. Send for book, Better Radio Reception. OW anyone can build the finest of receivers in only a few moments. No more wire bending or soldering. Merely attach a few ready cut, flexible eveletted leads and the job is done. The finished set is unsurpassed even by the costliest factory-built receiver. But most amazing is the new induc- tance principle incorporated in this last word in kits—called the Erla Circloid principle of amplification. Four vital improvements result from this great discovery, which are not found in ordinary sets. 1. Greater Distance: Erla * Balloon *Circloids have practically no external field, consequently do not affect adjacent coils or wiring circuits. This enables concentra- tion of proportionately higher amplifica- tion in each stage, with materially in- creased sensitivity and range. 2. More Volume: Increased radio fre- quency amplification made possible by Erla Balloon Circloids gives concert vol- ume to distant signals inaudible with receivers of cenventional type. 3. Increased Selectivity: Erla Balloon Circloids have no pick-up quality of their own. Hence only signals flowing in the antenna circuit are amplified. Static is greatly reduced for this reason. 4. Improved Tone Quality: The self- enclosed field of Erla Balloon Circloids Exclusive franchises are available to high class dealers in localities still open. Write or wire immedictely,

Dealers eliminates stray feed-backs between coils and consequently does away with mush- ing of signals and distortion due to this cause. Tone is crystal clear and perfectly lifelike, Write for free information on kit—also book See how 45 minutes of fun will give you one of the very finest sets known to radio science. EasyasA-B-Cto finish. Examine it at any Erla dealer's, or send the coupon for full information, illustrations and dia- grams free. Also ask for remarkable new book, “Better Radio Reception,”’ describing the sensational new Circloid principle. Enclose 10c for mailing and postage on book. ELECTRICAL RESEARCH LABORATORIES 2545 Cottage Grove Ave., Chicago *Trade Mark Registered. This sign identifies thorized Erla distribu. sore, All are equipped ‘give com; radio service. is ELECTRICAL RESEARCH LABORATORIES, 2545 Cottage Grove Ave., Chicago, U.S. A. O Send me free informa- tion on kit. O Enclose 10c for postage for book, “Better Radio Reception.” Clty.

Darche“CALL-ME” Electric ALARM and LIGHT CLOCK as an ‘‘alarm cloc! Get one with ist a litt —NO MONEY NEEDED. TELLS YOU HOW. ts, money-maker, no competition, is sight. A good punch board proposition. rite todav for our descriptive literature. An ideal GIFT for anv occasion. Mahog any finish. Size 10 1/2x81/2x4. DARCHE MFG, CO. 643 Washinston Bivd., Chicago, Hl. WELDING Mr. Mechanic, be in demand! Expert welding is in de- mand in every part of the world. Earn top wages or go into business for yourself. We train you at Home, in your Shop, or onthe Job. “Kerr’s Training Course for Welders’ is a thorough course in practical exnerience. covering all metals. It trains ao" in WHAT TO DO, WHY IT IS DONE, and HOW TO IT. Write at once for information (state if on own or have access to a welding outfit). rr’s Welding School, Box 1313, Los Angeles, California, (1)

© This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 19.

Write for Free Taxidermy Book. Tells ‘all about it. ‘know this art. Save your trophies. Bi 000 Write for Free a i Mi uates. * Inv witht THE r R 5 F ARI ( Protect Your Tools FromTheft. write with elec- tricity any name or design on the hard- est and finest tools and instruments,or apy metal, like writing on paper with pen-_er_ pencil. Complete Outfit

A one 5 e. Interest- ing illustrated circular free. Write to- : { | » ASARROGRAF PEN CO. << ED 1171-A East Stark St., Portland, Oregon

Page 110

Alice Higgie, a 13-year old Chicago girl $75.00 a week in vaudeville last summer. sicalact isconstantly in demand for clubs, lodges, hotels, radio studios and private entertainments. For a 15 minute act she receives $15.00—a dollar a minute!. Read what she says— Piaying a mu- nstrument is lots of fun. I wish every knew how omy % is and how quickly you can learn, especi- ally with Worlitzer instruments—they are so easy to play. Higgie. New Offer Learning to Play Made Easy We now furnish free with every W: ree litzer instrument a Special Scholar- ship in a nationally famous school of ds to play b music. This school has taught — san jay by a special home study method. Many of its graduates are successful professional musicians. ther you want to play for pleasure or for profit, hoose your favorite instrument and send for this New Iitustrates and describes musical instrument—more than 3000 ; es, many of them shown in full sai colors. All uine Wurlitzer instru- n rect from Wurlitzer and al offers on

rrr | The Rudolph Wurlitzer Co., Dept. 1786 \ 117E.4thSt. Cinciszati © 329 S. Wabash Ave. Chicago |\' 120W.42adSt.New York 250 StocktoSt.SanFrancisce ||! Send me your Free Book on musical instruments. Also | ‘our Free » Easy ent plan and special Free \\:\ ip Offer. Noob ion, \f

Copyright 1925, The Rudolph Wurliteer Co. POPULAR SCIENCE MONTHLY September,

Here Are the Rules in a Our Great $10,000 Contest This Month’s ‘What's Wrong’’ Pictures Appear on Pages 32 and 33 1 Every month for four months, beginning in * the June issue, PopULAR SCIENCE MONTHLY is printing a set of pictures of John and Mary Newly- wed. Each of these pictures shows Jéhn or Mary doing some simple “job about the home’”’ in an incorrect way. And, in addition, there is a_de- liberate error in the drawing of each picture. You are to tell us what two things are wrong in each picture and why they are wrong. 2 There are four complete monthly contests, * each of eight pictures. The first wasin the June issue, a second was in the July issue, the third in the August issue, and the last appears in this issue on pages 31, 32, and 33. In addition, there will be a Grand Prize Contest covering all of the 32 pictures printed in the four months of the contest. 3 PopuLar SCIENCE MONTHLY is awarding $10,- * 000 in 580 cash prizes for the best answers submitted in the contest. The cash prizes in each of the four monthly contests are as follows:

DEERE CES oc ce amb se oa & ewe $500 ee NIN 525 eh nia rers wen sooo wis a's $100 IME MEO oe ic, ods oc elke eo ose Sees $50 Next 5 Prizes, $10 each... ..cccccess $50 Next 60 Prizes, $5 each... ...cccccce $300 PURO ONL oon occas ae sereeese $1000 Sti NERS BORA... <.0500 0000500001 $4000 4 In addition, cash prizes in the Grand Contest ¢ will be paid as follows: EMP CL. cc ssc ose huss oe esies $2500 ee Ss ee ne ee oe $1000 UIE oes vin :cn akc vbeas shen ee $500 Next 5 Prizes, $50 each...........-. $250 Next 50 Prizes, $10 each...... sehens wenn Next 250 Prizes, $5 each..... seseeoe Seno Total Grand Prizes......sseccccesee $6000 er oe ee + eee ++ $10,000

HOW TO COMPETE

a In connection with each picture these ques- * tions must be answered: ‘‘What job is being performed improperly in this picture and how should it be done correctly? And (2) What error has the artist made in drawing the picture and why is it wrong?” A list of errors—two for each picture—is in the custody of the judges and will be used as a basis for the selection of the prize-winners. Prizes in all of the contests will be awarded to those persons who answer best the questions for the largest number of the pictures. It is provided, however, that as between contestants having the same number of correct solutions the selection of winners will be based upon (1) accuracy; (2) clear- ness; and (3) skill of presentation. In cases of ties, a duplicate award will be given to each contestant, Answers to each set of eight pictures 6. received not later than the thirtieth of tal month following the date of publication of the Maga, |, zine in which the pictures appear. Thus, to consideration in this month's contest, answers ty the eight pictures in this issue, published August 10, must reach the office of POPULAR SCIENCE Mo not later than September 30. Pictures received by : this date will be entered automatically in the! Grand Prize Contest also. Contestants, hog. ever, may enter for the Grand Prize Contest) any time before September 30, without ing | entered a monthly contest. Contestants ‘4 may hold the answers to all pictures until have a complete set of 32 before submitting answers, it being stipulated, however, that no ¢ vl 5a naam

entry will be received after September 30,

WHEN SUBMITTING ANSWERS

Contestants may submit as many answers a. they wish to pictures in either the mouth tests or in the Grand Prize Contest, but each mi be submitted in good faith. Answers may be g mitted on any kind of paper, but the writing’y be legible and on one side of the paper only. Each picture will be numbered plainly and contestants must attach to their answers either the co’ ing picture cut from the magazine or the numberof the picture. The winning of one or more moni prizes will not bar the winner from winning a Grand Prize, if he should submit answers. 8 All entries should be addressed to the Picture ¢ Contest Editor, POPULAR SCIENCE MONTRLY, 250 Fourth Avenue, New York City. Name and| address of the entrant must be written plainly ¢ |

each entry. An entry with insufficient postage not be received. The publishers cannot be respom

sible for delay, loss, or non-delivery of entries, / contribution entered in this contest will be retu 9 Prize-winners in this month's contest will} * announced in the February issue of -Popy | SciENCE MONTHLY, published January. _ The names of the winners of Grand Prizes i announced and the correct solutions published soon as possible after the close of the final mo | contest. st BO. 10 You pay nothing. Just prove your kno * and observation. You need not purchg POPULAR SCIENCE MONTHLY to compete. Yow borrow a copy from a friend or examine onc at of the offices of PopULAR SCIENCE MONTHLY! at public libraries free of charge. These conte are open to everybody, except employees of Pé ULAR SCIENCE MONTHLY and the Popular § ence Institute of Standards and their familie The officials of the Popular Science Institute) Standards will act as judges and their decision ¥ be final. Acceptance of these rules is an expre condition of each entry. i See pages 32 and 33 of this issue for the fi set of pictures in this remarkable contest. 4

F YOU have mislaid the June, July, and August issues of PopuLar ScreNcE MontTHLiy containing the first three sets of Contest pictures, and if your newsdealer cannot supply you, copies of these issues are available for your free use at the public libraries or at the offices of this magazine. Or, if you prefer, you can obtain copies at 25 cents each from the Picture Contest Editor, Popular Science Monthly, 250 Fourth Ave., New York City

© This seal on a radio or tool advertisement sigrifies the approval of the INSTITUTE OF STANDARDS. See page 19.

Suit I

Page 111

ures m rueth ol 0 ; 18, to ! +, answers to) d Au CE Mon 10, entries,” Al | be returned) ntest will be | of -Popy i ‘anuary, | Prizes: will be | published ai | final mo H ur kno not purehg te. You 1e onc atz MONTHLY hese conte yees of Pf Popular heir familie Institute | | decision is an expres) for the fit est. New York O Suite 1007 Woolworth Bldg. so MO * on Philadelphia, Pa., Office Suite 714-715 Liberty Bldg. = N a Victor Bldg. Washington, D. C., Office POPULAR SCIENCE MONTHLY DE-MARKS YRIGHTS OUR OFFER: Your first step ? Before disclosing an invention the inventor should write for our blank form “RECORD OF INVENTION.” This should be signed, witnessed and returned to us together with model or sketch and description of the inven- tion for INSPECTION and INSTRUCTIONS. NO CHARGE FOR THE ABOVE INFORMATION Our Four Books Mailed Free to Inventors Our Illustrated Guide Book HOW TO OBTAIN A FATENT Full instructions regarding U. S. Patents. | Our Methods, Terms, and 100 Mechanical Movements illustrated and described. OUR TRADE MARK BOOK Shows value and necessity of Trade Mark Protection. Information regarding Trade Marks and unfair competition in trade. OUR FOREIGN BOOK We have Direct Agencies in Foreign Countries, and secure Foreign Patents in shortest time and at lowest cost. Progress of Invention Description of World’s Most Pressing Problems by Leading Scientists and Inventors ALL COMMUNICATIONS AND DATA STRICTLY CONFIDENTIAL INTERFERENCE AND INFRINGEMENT SUITS PROSECUTED Private Office, Victor J. Evans, with View of Patent Office Through Window ls ighest References Prompt Attention Reasonable Terms ' VICTOR J. EVANS & CO., Patent Attorneys | FREE COUPON Main Offices: 760-9th Street, N. W., Washington, D, C, | Gentlemen: Please send me FREE OF CHARGE your | books as described above. ~~ Chicage, Ill, Office Suite 1114 Tacoma Bldg. Se Pittsburgh, Pa., Office Suite 514 Empire Bldg. . San Francisco, Cal., Office Suite 1010 Hobart Bldg. © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 19.

Page 112

124 Mechanical Engineering Learn at Home! Employers are looking for men with mechanical ability. There is an easy, delightful way in which you can learn right at home in spare time. For 33 years the Interna- tional Correspondence Schools have been giving men and women just the training they need for success in me- chanical engineering and more than 300 other subjects. Hundreds of thousands have stepped into good positions through I. C. S. help. Let the I. C. S. help you. Choose the work you like best in the coupon below, then mark and mail it today. This doesn’t obligate you in the least but it will bring you information that will start you on a successful career. This is wour chance. Mark and mail the coupon now. oo ae eee oes a TEAR OUT HEAEOS o-oo eo INTERNATIONAL CORRESPONDENCE SCHOOLS Box 7667-D, Scranton, Penna. Explain, without obligating me, how I can pat for the position, or in the subject, before which I mark X. ELEOTRIOAL ENGINEER CHEMIOAL ENGINEER Electrician Pharm: Electric Wiring SALESMANSHIP Electric Lighting ADVERTISING MAN oe Car Running Penny ale 7 a - ee a aera RAILROADPOSITION Electrie ILLUS TOR Lx crete a vate aed DESIGNER Gracileal Telepho y BUSINESS MANAGEMENT EOHANIOAL ENGINEER aanpen Mechanical Draftsme= poctosee Coeres Gone a Shop Practice Stenographer and Typist ihe er Cert. Pub. Accountant Gas Engineer Traffic Mana; it Surveying and Mapping GOOD ENGLISH ARCHITECT CIVIL SERVICE Arehitectaral Drafteman Railway Mail Clerk Architects’ Blue Prints Textile Overseer or Supt. Peery tke HEATING AGRICULTURE orker PoultryRaising Spanish Navigator Automobiles f- RADIO Name Present Business ee Occupati Address Street and No City. State Canadians may send this coupon to International Corre- spondence Schools Canadian, Limited, Montreal, Canada EasytoDraw Cartoons When Shown in the RIGHT WAY Some of the cleverest cartoonists and comic artists learned how to draw in their spare time by tpeving Cartoonist Evans’ Simple and Easy to Learn Metho are now MAKING GOOD MONEY. Send one of your drawings, and let Mr. Evans see if you have ability teceive the Portfolio of Cartoons aud full details about the course. It is not expensive. THE W. L. EVANS SCHOOL OF CARTOONING 825 Leader Building Cleveland, Ohio POPULAR SCIENCE MONTHLY Cracks in the Earth Menace American Cities (Continued from page 22) ually are becoming larger, while the continents are being compressed so that the land areas are rising as the sea front retreats. The contours of the United States show this. It is believed that the shores of the American continent once were connected with Africa, or at least were separated only by a narrow strait. Since the Atlantic has been enlarged, the plateaus in the western states and the mountain ranges all have been raised considerably. These movements always have been con- nected with volcanic activities. The land areas have been faulted by condensa- tional waves caused by the falling in of large areas of the sea floor; by gravita- tional waves caused by landslides, near faults in the rock masses, and by station- ary waves set up by local deformations caused by landslides and similar move- ments. All of these have been in opera- tion along the Pacific coast earthquake zone. Arizona, Kansas, Oklahoma, and Ar- kansas are the seats of frequent earth- quake shocks. Quakes, of more or less severity, are felt in those states annually. The whole valley of the Mississippi is un- doubtedly situated on a line of faults, constituting an earthquake zone. Ala- bama and Tennessee have earthquake records showing that the earth’s crust in those states is not strong. The Virginias are on a similar line of weakness and this line can be traced along the Atlantic coast to Canada and Newfoundland. There is a pronounced fault in the sea-bed off the coast of Maine which appears to be connected with faults running past New York. The St. Lawrence, the Great Lakes, and a series of lakes and waterways running through Manitoba, Alberta, and Sas- katchewan and through the Mackenzie Valley to the Arctic—these form a great line of faulting along which most of the earthquakes experienced in North America are felt. A Clinic by Long Distance Yipes they looked at a photograph thrown on a screen, representing the heartbeat of a patient, 1500 doctors at Atlantic City recently listened to a Chicago physician’s diagnosis coming over 1000 miles of telephone wires. The first long distance medical clinic was a dra- matic demonstration of how distance soon will be practically meaningless in the diagnosis of disease. The patient’s heart was examined with a stethoscope. By means of a new appa- ratus- developed by Dr. H. B. Williams of Columbia University and the Bell Tele- phone laboratories, a chart of his heart- beat, called a “‘stethogram,” was made. This was sent to Chicago in seven min- utes by the new method of sending pic- tures by wire. Doctor James Greer of Chicago made a diagnosis and, when the stethogram was thrown on the screen in Atlantic City, gave the diagnosis over the telephone. It was amplified so that all could hear it. © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 19. September, Here's Carcer for Get into this won- derful, big-paying 2 Profession. Hun- dreds of openings now in Motion Pic- ture Camera Work, Portrait and Com- mercial Photography. Learn at home, Big money while learning, “Dw °250 a Week High salaried positions everywhere or open your own studio. ‘*My business aver- ages 3700 to $1000 a week,’” writes Michael Gallo. Others doing equally well. 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4 99 “It’s a High Pressure Job (Continued from page 37) the risk those chaps up there are — asd day. If it was a risky job, how do you suppose they put them two big vehicle tunnels under the Hudson River without losin’ a man? Twelve hundred sandhogs worked on that job, an’ I was one o’ them. Never less than 390 of us at work at once, an’ the only two men killed on the job was not sand- hogs. One fell down a shaft an’ the other got caught in the works of a pump. How many big buildings kill as few iron- workers as that? “GORE, there’s risks, but nothing like | what they used to be. When they started the very first try at< tunnel under the Hudson, more’n 50 years ago, the tunnel caved an’ 20 men was druwned. That was before they knew how to work the air like they do now. “Y’ see, down in the caisson or out at the tunnel headin’, the trick is to keep the cuttin’ edges covered with the stuff you’re workin’ in—mud or clay or whatever it is. If your caisson is level an’ your air pressure is right, you don’t have no trouble. You’ve got to have air enough to equalize the water pressure and not enough to blow out the mud. You're diggin’ from the middle toward the edges all the time, and shovin’ the caisson down or the tunnel headin’ across as fast as you can get to the edges. Now, if your mud blows out, you’ve got a blowout, and the air alone can’t hold the water back, unless you can get more pressure in a big hurry, an’ you can’t always do that. “There’s always plenty of bags of hay and bags of clay handy, to plug up any hole where the air is escapin’. You can tell by the sound when the leak begins. An’ sometimes, when there ain’t enough of that sort of stuff to plug the hole, there’s other ways. I mind me once—it was in the Pennsylvania tunnel—when Red Kelly, that was workin’ alongside o’ me, sat in a blowhole to stop it while we got up the hay bags! It’s a good thing most sandhogs ain’t skinny. wT ERE ain’t much danger if the boss keeps his head. There was a blowout one night in the Manhattan Bridge caisson. There was eight of us inside, workin’ in about 35 pounds of air, pretty near 80 feet down; Jimmy Durkin, Jimmy Appleby, an’ myself, an’ five Swedes. The air chamber was about 10 feet above our heads, an’ there was a ladder to the shaft openin’. The shaft would only take in one man at a time. One side of the caisson rested on loose silt, an’ needed watchin’ all the time. “Well, we was near the end o’ the shift when one 0’ the Swedes hollered, ‘Look at dat!’ We looked, an’ the silt was crumblin’. Next we knew, it blew out like an explosion an’ the water rushed in. Four vu’ them Swedes made a rush for the ladder, an’ we might all have been drowned if the other Swede hadn’t picked up a pick handle and whacked ’em over the head. Then we got out, one at a time, with water up to our waists before the last one went up the ladder. (Continued on page 126) POPULAR SCIENCE MONTHLY

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126 POPULAR SCIENCE MONTHLY SMASH Your Way Through to SUCCESS! IFE’ s race is to the TRONG. The Saat survive. i The weakling perishes. i Your Success in busi- i ness, in society, in all the relations of life, depends fundamentally on your Physical Health and Strength. If you havesome physi- cal weakness gnawing at your vitals and rob- bing you of the very essence of success, you are a beaten man. You Can WIN | Life’s biggest prizes are i YOURS if you have the Physical Power to DEMAND them. } Where do you stand? H Are you a_ business } drudge—one of the “Yes, Sir’’ boys, hum- bly taking orders from others who haven't half your ability but who # DO have a surplus of } Health and Energy? } Or—are you the fight- ing, planning, DOING sort of MAN—the man who leads and directs Hother men—the man i who is respected and looked up to by men and women alike? Are you? You CAN be It’s EASY Lone! 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Startling Book FREE STRONGFORTISM—the Science that makes physical and mental super-men out of weaklings, that makes business giants, social successes and leaders in trade and commerce out of weak, disease-racked, discouraged, hopeless men, is fully described in my new book, ‘‘Promotion and Conservation of Health, Strength and Mental “i Let me send you a copy of this FREE book, beautifully illustrated from living figures and crammed with startling facts. Fill out the Free Consultation Coupon and send to me TODAY with ten cents (one dime) to cover mailing cost. LIONEL STRONGFORT Physical and Health Specialist Dept. 17 Newark, New Jersey CONSULTATION COUPON—Absolutely Confidential Lionel Strongfort, Dept. 17, Newark, N. J. Please send me your big book, ‘‘Promotion and Conservation of Health Strength and Mental En- ergy. I enclose ten cents (one dime) for postage. Send me special information on subjects marked (x) below without obligation. ‘olds — Despondency —Catarrh ——Skin Disorders —Too Fat —Debility —Too Thin —Torpid Liver —Stomach Trouble —Muscular Development —Flat Chest —Great Strength —Bad Blood —Rupture —Nervousness —Lumbago —Constipation —Neuralgia —Bad Habits I ew Ot ec Et BO irkis hike sxinantg poe en mud As eanaebec a SE ae Ca Cee aaa Address . | ‘It’s a High Pressure Job”’ (Continued from page 125) “If the pumps don’t stop there'll always be air enough to breathe if you can keep your head above water. Jimmy Sullivan, that I was tellin’ you about, told me of a blowout when they was buildin’ the Forth bridge, in Scotland. Him an’ the other miners was trapped an’ the air-lock door jammed. They had just five inches of space between the water and the floor of the lock, just enough to keep their noses clear while they hung on an’ waited for help. “You just got to remember that the water’ll only rise so high if all the edges are under water, like when you put a tumbler upside down into a dish of water. One night, in the Long Island tunnel, there was a blowout an’ when the men got into the lock there was one missin’. It looked like he was a goner, but when they got the hole plugged—they had to send a diver down to do it—an’ pumped the water out, there he was. He’d found a place up at the top o’ the tunnel where he could hang on, an’ he’d hung on. UNNEL work is more ticklish than caisson work, to my thinkin’. The pressures ain’t so high, but there’s more danger of a blowout. In a caisson, if it’s level, the water pressure’s the same all around the edges; but in a tunnel it’s higher at the bottom than at the top. You can see that, can’t you? Take the vehicle tunnel. That’s nearly 30 feet from top to bottom. That means the pressure at the bottom is some 13 pounds more’n it is at the top. Now, you’ve got to have air enough to equalize that bottom pressure, an’ overhead you’ve got only a thin layer of mud between you an’ the river. There’s where the danger of blowouts comes. Where the bottom of the river’s soft, they put down a clay blanket, 10 or 20 feet thick, an’ dredge it out afterwards, to hold the air in an’ the water out, but close inshore an’ crossin’ a shallow channel they can’t always do that. “That’s how the funniest accident that ever happened to a sandhog came about. They was puttin’ the first subway tunnel across from Manhattan to Brooklyn, an’ the Brooklyn end was just a little ways out from the pierhead line, at Joralemon Street. It was all soft mud, with piles stickin’ down through it, an’ one day she blew out with a bang. LL the gang that was workin’ in the headin’ made the air lock but one, when the water rushed in. Dick Creedon was missin’, an’ they was a solemn gang that filed out o’ the air lock to report to the super. Creedon’s side partner, Jimmy O’Connor, had been killed in an accident in the tunnel only a few days before, an’ now Dick was gone. “But when they got to the super’s office, there was Dick Creedon, huggin’ the stove! Some of ’em thought first it was Dick’s ghost. What happened was this: “The air had caught Dick and blown him right through the river bottom. I was talkin’ a while ago about a sandhog havin’ no place to fall to. Well, there is (Continued on page 127) © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. Living Room 04g Prete 2 U4 SU (Ee ey ae - Hundreds of other bargains in our FREE CATALOG WHOLESALE Mail — Today « PARAMOUNT ELECTRIC Co. “oor © Please send me FREE jour Bip Bocnis Coe eh — Name “ ® Address "oem = P.O. State ~ w Occ : EAT Witho a new invention does away with coalor wood. 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ME sestember, 1925

ie “It’s a High Pressure Job’’ (Continued from page 126) ay he can fall, an’ that’s up. That's the way Dick Creedon fell, up. “Right up through the mud, 10 feet of it, and 30 feet of water, an’ he kept on goin’. I didn’t see it, but I’ve heard him tell about it, many’s the time. The water squirted up like a fountain, 10 feet or so above the surface, with Dick palanced on top of it like one o’ these balls you see in a shootin’ gallery, whirlin’ around an’ yellin’ at the top of his voice. Then he fell off the fountain an’ into the East River, an’ a boatman picked him up. +p ome Sipht

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Pa tN noe ae en pee rree ey i ; “T don’t know where Dick is now. Last | store prices. We give you a wonderful liné of free territory. No obligation. Simply fill out and a) ; in our I heard he was fired off a job in Buffalo | samples—you simply take the orders, collect ty dunvinn Woe But don’t lose $10 a day ; p Hours, because the newspapers printed that | your na onapanadiiints deliver and collect. Charles Hope, FASHION WEAR SHIRT CO. yy day story about him, an’ he had to spend so Big Money The First Day 1200-20 Jackson St., Dept. L-171,Cincinnati, Ohio ‘ Opens much time bein’ a hero he didn’t have no Every man is a prospect for these shirts. You gu=a= hd ‘ ‘ k. But he wasn” the onl can go into offices, factories, garages, etc.,and Fashion Wear Shirt Company cet , PHILA, PA, time to work. u v : Y | clean up $10 to $20 in an hour's time. Fred Erman- § 1200-20 Jackson St., Dept. L-171 Cincinnati, Ohio i atalog— : one that had the same _ experience. — —. in one afternoon spare time. — Gentlemen: Send meat once full details of your Henry made $25 in one day. An Ohio man writes # free territory and free sample case offer. Thi ———; Paddy Egan was blown up through the This is the biggest whirlwind seller I have ever % does ner geet boven henge i peslinipign = ——— Thames the same way, on the Blackwall | run across in my ten years of experience as a sales- Stale i. Th 2 ae anole thak man.” Scores of men write like that. No matter if PRONE S i caesldeins ccades tasers c ly ee

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i, SEP gate x i tt Md tt - HIGH SCHOOL COURSE IN TWO YEARS YOU ARE BADLY if you lack HANDICAPPED HiehSchool training. You cannot attain business or social prominence. You are barred from a successful business career, from the leading professions, from well- § paid civil service jobs, from teaching and college entrance. In fact, em- ployers of practically all worth-while positions demand High School train- ing. You can’t hope to succeed in the face of this handicap. But you can remove it. Let the American School help you. FIT YOURSELF FOR A BIG FUTURE This course, which has been prepared by some of America’s leading professors, will broaden your mind, and make you keen, alert and capable. It is com- plete, simplified and up-to-date. It covers all subjects given in a resident school and meets all requirements of a High School training. From the first lesson to the last you are care- fully examined and coached. USE SPARE TIME ONLY Most people sdle away jifty hours a week. Probably you do. Use only one-fifth of your wasted hours for study and you can remove your present handicap within two years. You will enjoy the lessons and the knowledge you will gain will well repay the time spent in study. Check and mail the coupon NOW for full particulars and Free Bulletin, American School Dept. H-675_ . Drexel Ave. and 58th Size Chicado COS at WARE (IR OTe A AA WE a A, REL American School : Dept. H-675, Drexel Ave. & 58th St., Chicago Send me full information on the subject checked and how you will help me win success, neral ...... Vocational Guid Name - POPULAR SCIENCE MONTHLY AAA. Birth of the Airplane (Continued from page 29) sections, and joining these on the machine. ‘“‘He’s making a tent,’’ thought the passer-by; “fishing trip down river, I guess.” The brothers built a shed camp de luxe for the second season at Kitty Hawk. As before, Orville officiated as chef and in this domestic field he fairly rivaled his brother at the sewing-machine. Orville put mathematics into his kitchen. The canned goods stood on their shelves in the select order of soldiers at dress parade, The eggs were in a rack, visible and countable. There was a gasoline cook- stove. Galstamatety, this luxury and effi- ciency were somewhat blighted by hosts of mosquitoes. They were foiled only by smudges that choked the experimenters. Another vexation had to do with the Shows all Buescher models, ‘st | hart; of famous naan ate m . eateas, fendi oes acopy. Mention TH! other instrument i bo hterested No obligation, Write to bela ny 707 B division of labor in dish-washing. There was a camp mate, not Wilbur, who left all of this chore to the cook. keeping the latter busy in the kitchen to the neglect of his aerial activity. CTAVE CHANUTE visited the camp, saw the brothers’ second-year they were ahead of the world in the gliding art. But they, without admitting it to any one, were deeply discouraged. They knew their machine was no improvement on the first one; in fact, it behaved worse. They had more evidence that the classic air tables were incorrect. The mystery of the air seemed insoluble. At this time Wilbur agreed with the pessimism of Prof. Simon Newcomb as to the possi- bility of the airplane, and even went further than that eminent astronomer by saying: “Man won’t be flying for a thousand years!” Wilbur, in his depressed mood, was only exaggerating by 998 years. Skeeters, heat, no ice, liquid butter, spoiled beefsteak, and a cantankerous glider—you can understand how the brothers felt. For an address to be made by him that fall before a scientific group in Chicago, Wilbur included criticism of the classic air tables. Meanwhile, at home, Orville rigged an air tunnel with a fan driven by a homemade two-cylinder gas engine. He found the classic figures right! He let Wilbur know in a hurry and the latter toned down his criticism, lest he should mislead the distinguished scientists of Chicago. The scrupulous brothers were ylanning more censorship of the address in its printed form, when they found they were right in the first place and really had nothing to retract! Orville only had verified with his air tunnel a few of the old figures and these few had chanced to be about right, while the majority were away off. AVANTS had spent vast sums in the effort to measure air pressure. The Wrights now succeeded with an outfit that cost about 15 dollars. Their fan was on an emery-wheel shaft, their tunnel was of wood, 16 inches square and eight feet (Continued on page 129) tryouts and complimented them, saying - Easy to Play Easy to Pay CLYDE DOERR Of Clyde Doerr and to His Orchestra, with Thre his Buescher A sons sent fren fis True-Tone Sax- easy start. In . Fon 8 ai ophone. you can be playing”, Doma tunes. 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Desk A. Erie, Pa. © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 19.

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Observe the rigid construction of this unit, the exactness of every detail, the size of the magnets. The unit is the reason. See one at your dealers today. Kellogg Switchboard & Supply Co. 1066 W. Adams Street, Chicago, III. With every Kellogg radio part. Use — Is The Test. aU! Have You AN INVENTION? If so the WORLD PROGRESS will show you how to Protect and Profit From Your Ideas Sample copy free. One year’s subscription 40c. Send for free book, “WHAT TO INVENT” containing Suggestions to Inventors as to Inventions Needed. We invite manufacturers to address us regarding inventions they want. WORLD PROGRESS PUB. CO., INC. Room 202 Victor Bidg. Washington, D. C. BOOK, coale Prices and ‘Sample Kit. ELLINGER TIRE & RUBBER CO, HW Dept. 310, Philadelphia, Pa.,or Kansas City,™ oy arrive at school 2 miles POPULAR SCIENCE MONTHLY Birth of the Airplane (Continued from page 128) | long. Bits of old hacksaw blades and | other junk lying round their shop con- tributed to the make-up of the testing | devices. The air tables that they made | in the winter of 1901-2 were applied in all | their later construction of aerial vehicles. If we should estimate the first-found | warping principle as one-quarter of the flying secret, we may give 50 per cent of | the credit to the aerodynamic research of the Wrights. The final 25-per-cent ele- ment will be told of as it came, last. AGAIN Wilbur toiled at the sewing- machine in the back yard of the Day- ton home. A new glider, third model, em- bodying the newly discovered laws of air pressure, was taken to Kitty Hawk in the late summer of 1902. Rather, the parts were taken, and the machine assembled in camp. Amid scientific observation in his diary, Orville found time to record the life and death history of a mouse that in- vaded his kitchen. The brothers were never too busy to notice everything about them. A mouse, a razorback pig in camp, the antics of children, pleased them. The quiet young men laughed quietly at many things, including their own mishaps. Rarely if ever did they lose their even, good temper. The new glider, 305 square feet in wing area and weighing 116 pounds, had its virtues and also some alarming faults. The operator, who lay on his stomach as usual, clutching the controls, had to shimmy quickly to shift his weight and avoid a wreck. There was peril despite plenty of sand to fall on. The brothers knew that Lilienthal and Pilcher had been killed by falling from heights no more than that of a shade tree. At this time Orville did take a drop from about 25 feet up, which partly smashed the glider. A vertical tail was a new feature of this year’s machine. That tail—what was wrong with it? Somehow it did not act asitshould. It was rigid, you know. Now some one may chortle an easy answer: Look at all nature. Is a dog’s tail rigid, or does it wag? But the flying machine would not have gone far if it had been based on zoology. Too many dreamers copied bird shapes. |S oeeepinge all that may be, the fact is that on the night of October 2, 1902, | Orville could not sleep. Doubtless it was stuffy among the ceiling beams of the camp shed where he had slung a bed of canvas. A great thought came to him. Let that tail be movable! Although he did not know it that night, as he moved restlessly on the canvas, the invention of the airplane was in effect completed. This was the solution of the last 25 per cent of the problem of air conquest. Orville did have in mind the object of the movable vertical tail, or rudder. It was to counteract the speed of the high or turned-up wing, and thus aid in the : | | Earle E. Liederman The Muscle Builder Author of *‘ Muacle Building ,’’ ** Science of Wrestling,"* ** Secrets of Strength,’? "Here's Health," ste. = MUSRY WOSCLES When you looked in the mirror this morning, did an imitation of a real man stare you in the face? Chest hollow as a bent mud-guard? Shoulders stooped like a tired old hack horse? Arms like ropes with knots on the end? Neck scrawny as an old crow’s? Legs thin as pipe-stems? Muscles soft and flabby? How can you expect to amount to anything if your body is like something the cat dragged in? Mushy muscles— They Are My Meat as thousands upon thousands of my pupils will tell you. I take them as they come, weak and flabby. Then I start working! I make your muscles hard as steel. I make your chest big and deep. -I give you legs and arms that fill your clothes. Your friends won’t know you. I fill you with pep and ambition. When you wake up in the morning, you spring out of bed full of fire and pep. “Bring on your wild cats” is the way you feel. You are ready for a full day’s work. You just thrill with vitality. I Am the Muscle Builder That’s what they callme. Why? Because I take the mush out of muscles! When you think of muscle, think of me! I build strong bodies. Just any kind of exercise won't do. A lot of other fellows thought they could do it themselves. They soon found they were wrong. This is my job. I’ve studied it. I’ve watched my pupils develop. 1 know it’s good. In fact, I don’t promise results. I guarantee them. In thirty days I will put one full inch of muscles on your arm. I will put twa inches on your chest at the same time. But that’s just a starter to show what I can do. I'll put muscle up and down your back. I'll build a wall of armor around your bread-basket that will stop a battering ram! I'll strengthen every muscle in and around your vital organs! I'll make a he-man, up-and-at-em-fellow out of you. Sounds good, eh? You're darn right it’s good. It’s wonderful, Remember, I guarantee it. Come on. Let’s get going right now. Don’t lose a minute. Send for My New Book “MUSCULAR DEVELOPMENT” It is FREE It contains forty-five full page photographs of myself and some of the many prize-winning pupils I oon trained. Some of these came to me as pitiful weaklings. Imploring me to help them. k them over now and you will marvel at their present physiques. This book will prove an impetus and a real inspiration to you. It will thrill you through and through. All I ask is 10 cents to cover the cost of wrapping and mailing and it is yours to keep. This will not obligate you at all, but for the sake of your future health and happiness, do not put it off. Send to-day—right now, before you turn this page. EARLE E. LIEDERMAN maintenance of sidewise balance. A rud- der it was, but not to steer with; its job being to keep equilibrium. The minds of the brothers were geared in beautiful harmony. As Wilbur (Continued on page 130) Dept. 1309 305 Broadway New York City T canes E. LIEDERMAN “a Dept. 1309, 305 Broadway, New York City | 1 Dear Sir:—I enclose herewith 10 cents, for which | you are to send me, without any obligation on my | part whatever, a copy of your latest book, ‘‘Muscular ] Development.’’ (Please write or print plainly.) I | CRY nn nnescwsetnndactwestsuleg State.. Lecce seme ome cus com su ann iets wits sien ieonl atieeiinobebl

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ed : an Hour! “Every hour I spent on my I. C. S. Course has been worth $95 to me! My position, my $5000 a year income, my home, my Eamily’s happiness—I owe it all to my spare-time training with the Interna- ttional Correspondence Schools!” Every mail brings letters from sysme of the thousands of I. C. S. students tell- ing of promotions or increases in salary as the rewards of spare-time study, What are you doing with the hours after supper? Can you afford to let them slip by un- improved when you can easily make them mean s0 much? One hour 2 day spent with the {. C. S. will prepare you for the position you want in the work you like best. Yes, it will! Put it up to us to proveit. _ Mail the Coupon for Free Booklet ae INTERNATIONAL CORRESPONDENCE SCHOOLS Box 7666-D, Scranton, Penna. Without cost or obligation, please send me one of your booklets and tell me how I can qualify for the position or in the subject before which I have marked an X: BUSINESS TRAINING COURSES Salesmanship Advertising Better Letters Show Card Lettering Law Stenography and Typing and Banking Law Business English (including C.P.A.) LL) Civil Service Accounting Railway Mail Clerk ; 4 Cemmon School Subjects High School Subjects French Llustrating TECHNICAL AND INDUSTRIAL COURSES Electrical Engineering Architect Architects’ Blue Prints Contractor and Builder Architectural Draftsman Concrete Builder Railroad Positions Structural Engineer Gas Engine Operating Chemistry 1] Pharmacy Civil Engineer Automobile Work Surveying and Mapping Airplane Engines ‘Metallurgy O Mining Agriculture and Poultry Steam Engineering () Radio Mathematics Name Btreet_ 3-6-24 Se State IG ia geckdscptecosectnnsgetecepronesccbecbecheoesdbesvoeseses Persons residing in Canada should serid this coupon to the Anternational Correspondence Schools Canadian, Limited, Mon*eal, Canada Tool Cases for’ Machinists, Car- penters and Tool Makers; none better; thirty styles. Quarter- ed oak and metal cov- ered, Ask for booklet. . **Built for Service”’ The Pilliod Lumber Co., Swantou, Ohio POPULAR SCIENCE MONTHLY Amateur Mechanics—Model Wade Makers—Students Bench-Lathe Cap: 4” dia. x 12" ngth. Sliderest has trav- el e:tire length of bed. -screw le bed. Hollow spindle. Tesaing, * », Grilling, crdfie, rset curtos: © 1 Lathe, plain headstock $28.00 ‘ , back-geared headstock - - - - $58. Grits Bee gaccae™ “AP QEnC EStANG Sept. BS. 4, 120 Liberty Street, New York Birth of the Airplane (Continued from page 129) had developed the other’s hinged wings into the warping principle through the medium of a twisted box, so now he accepted and improved upon Orville’s movable rudder. He said they should connect rudder and wings so as to warp and wag, as it were, simultaneously with one control. Within two days the brothers began to rig up a movable rudder con- nected by wires with the warping control. And at last they had the thrill of riding the air with a success unprecedented. Never before had man thus balanced him- self in the atmosphere. Never had a glider behaved so tractably, responsive to iw helm. HERE were flights beyond 600 feet in 85-mile breezes. Within a fortnight the number of trips amounted to some- thing around 700. Fore andaft balance had been rather easy from the start. Now that lateral balance and steerability had been secured, what remained? Only to equip the glider with engine and propeller. The birth of the airplane should really be dated in October, 1902, instead of more than a year later when the first power flight occurred. That glider em- bodied all basic principles of air navi- gation. Before leaving camp in the latter part of that October, the Wrights started plans for a y.ower machine and also sketched an application for a patent. The patent was aimed to secure the honors of priority in a scientific achievement, for the broth- ers did not foresee commercial value in their invention. During the following winter at home they built a crude four-cylinder gas en- gir.2. They designed it, had aluminum castings made in a local foundry, did the machining in their own shop. As evidence of crudity, it developed about 12 horse- power and weighed 20 pounds to the horsepower. The homemade engine let out such a tornado roar that scared neighbors rushed into the shop to see what was up, and the gas fumes sickened Charley Taylor, the sole and faithful employee of the Wrights. [* WAS a harder job to design propellers, but after due mental wrestling, the brothers saw they could do it from the formulas of their air tables. They ob- tained a screw efficiency of 66 per cent, which was about a third better than any one before had realized. The wing span of the power biplane was 40 feet, its area 510 square feet, with 48 square feet more given to a duplex wing in front. The total weight of the machine, with either of the 145-pound brothers aboard (lying face down, hands on forward controls, hips harnessed for other work), was 750 pounds. This is the pioneer machine that Orville Wright purposes to send to an English museum. In March, 1908, nine months before this airplane took off at Kitty Hawk, the Wrights applied for a patent on their basic discoveries. On the fourth sojourn in a sandy desert (Continued on page 131) © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 19. September, 1925 ZIP-ZIP LET’S GO Boys . Y No matter where you ; £0, Cam) hunting, fishing, boating, to ats country, the seashore or the moun. tains, you will need a Zip-Zi peor. spomeands of boys are 4 uppy with this wond shooter. If your dealer — ZAD-Zip happens_ not to have them order them from as. ZiP-ZIP shooter complete only 35¢ or three for $1.00 pre- paid. Send stamps, coin or money order. C0., Dept. 22, Columbia, $, ¢ quab Book FREE m4 Squabs selling at highest prices ever kno Greatest market for 20 years. Make mone breeding them. Raised in one month, We ship everywhere our famous breeding stock and supplies. Established 24 years, Write now for big illustrated free book, How to Make Money Breeding Sauabs; PLYMOUTH ROCK SQUAB ¢o G16 HSt., Melrose 11 EE ESET SE =e ~ebends, Mon I will put you in business as my Dirgcr FACTORY AGENT AND JOBBER, to take orders for my full line of candies, chocolate bars, mints and chewing gum. Unlimited opportunities for hustlers. No experience needed. I furnish everything. Every store and everybody buys. Work spare time or fulltime. Write today for catalog, selling plan and FREE SAMPLES. Exclusive territory. ACT QUICK, MILTON , 807 Jack St., Cincl 1. 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aber, 1995 “ IP | BOYs . 30, Cam: ing, teas r a the September, 1925 POPULAR SCIENCE MONTHLY 131 — os oe Birth of the Airplane (Continued from page 130) “41: sight and sound of the thundering eae. the inventors had many little adventures. These they recorded in home letters with comical appreciation, almost to the dwarfing of their high objective. There was a midnight battle with a tar- paper roof in a gale. Orville invented a French-drip coffee-pot to save the use of eggs. A carbide can was converted into a wood stove. As medical advice to Charley Taylor, who wrote from Dayton that he suffered from unsteady legs, Orville sug- gested bracing his legs with the truss system employed in his biplane. A? THIS time Wilbur was 36 and Or- ville 32. Both were of slender, ath- letic build. The elder stood 5 feet 101% inches, or a trifle less than two inches above his brother. They were both smooth shaven and both had grayish blue eyes. The propeller shafts twisted under strain of the first engine test at Kitty Hawk. In the next test the propeller sprockets came loose. ; Things looked dark when a third acci- dent—a bit of metal broken out of a new shaft—occurred in late November. Now the power machine was again helpless, before ever it had been tried in the air. Four miles through deep sand, lugging two suitcases filled mostly with metal gear, hiked Orville to Kitty Hawk. He took a boat to Elizabeth City and then a northbound train. When he arrived in Dayton he hadn’t five cents left for car- fare. Weighted down with those suit- cases, he walked 114 miles to his home. It took a week to obtain new shafts of spring steel, and Orville hustled back to Kitty Hawk with them. Thank heaven, the hoodoo was over. The power plant stood the Saturday test with engine aroar, screws speeding. Wilbur was first of mankind to fly in a power machine, on Monday, Decem- ber 14, three days before the official, accepted date for that event. To be sure, his time was but 3% seconds and his distance 105 feet, and the hop ended in a partial wreck. ()PVELLE went up first on the com- memorated December 17, 19038, re- maining about 12 seconds in the air, but not much exceeding his brother’s previous distance. Wilbur now followed in a sim- ilar flight. Orville had another turn of short duration. Then, just at noon, Wilbur stepped forward for the fourth and last flight. It was a cold, dull day. Whitecaps were visible on the near-by Atlantic and ice was forming in Albemarle Sound. The aviators were chilly, having no special garments for their work. Doubtless the five spectators—three men of the govern- ment life-saving station, a lumber buyer, and a 16-year-old boy—were also cold and wished to have the affair over. Even the muse of history, we may imagine, got impatient and had to blow on her stylus- holding fingers to keep them warm. ' Wilbur hastened to oblige. He covered a ground distance of 852 feet in 59 seconds, } whereupon Clio said, “So that’s that,” and the meeting adjourned sine die. M ADE with absolute precision, the perfect balance of Marathon Tubes insures the best possible reception. _ ATRIUMPH IN RADIO TUBES Manufactured by NORTHERN MFG. CO. Newark, New Jersey LL that the name implies. In the orange-and- blue carton with the Marathon Runner. Every tube guaranteed. HON © $75. to $150. Weekly INSTANT WELD Welds RubberIn- stantly. Better, quicker, and easier on racanising. ONCE ON—AL- WA ON. No Heat or Cement re- quired. Repeat orders sure. Big prof- its. Appoint sub agents. Write today. TOURISTS’ PRIDE MFG. Co. fy Desk No. 30-1 Minneapolis, Minn, TIGHTEN THAT LOOSE DRAWER HANDLE WITH SMOOTH-ON No.1 ACK the Smooth-On around the bolt, washer and on the threads, and the handle can never again come loose. Try the same trick on any loose tool, knife, or umbrella, handle, door knob, etc., and the result _— will surprise you. Smooth-On No. 1 is al- i so sure cure for leaks of H water, steam, fire, etc., at 7 Just the thing for repair- ih ing radiators, heating yf boilers, furnaces, tanks, # pipes, leaky pails, etc. Keep a can on hand for Write for FREE BOOK) ©™ergencies. Sold in 7-0z., 1-lb. and 5-lb. tins at all live supply siores SMOOTH-ON MFG. CO., Dept. 58 574 Communipaw Ave., Jersey City, N. J. Inventor’s Universal Educator contains 900 mechanical movements; 40 per- petual motions. Tells how to obtain and sell Patents, Suggests new ideas. Explains how to select your attorney and avoid patent sharks, Special price (for a limited time) $1.00 post paid. Albert E. 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Approval We will send this famous watch direct to you, express prepaid on FREE approval. Examine watch and be convinced it’s the best watch buy you ever saw. You save 1-3 to 1-2 your money by purchasing a Santa Fe Special Watch. We trust you—Wear watch while paying for it SEND FOR FREE WATCH BOOK my, Gip the coupon, fill out and receive the FREE WATCH BOOK. All the newest watch case de- signs in white or green gold, fancy shapes and thin models are shown. Read our easy payment offer. Select the watch you would like to see, we will send it to you on approval, express prepaid. Wear the watch 30 days FREE—return at our expense if not fully satisfied. Ask for Santa Fe Ladies’ Bracelet Watch folaer and Diamond folder. SANTA FE WATCH Co. 980 Thomas Bidg., Topeka, Kan, The Home of the Great Santa Railway, ee Santa Fe Watch Co. 23 e

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oll Design, Workmanship, en ae “har and finish of the highest _— order are found in all Gerstner Tool Cases for Toolmakers and Machinists They please. Write for free catalog. H. GERSTNER & SONS 521 Columbia St., Dayton, 0. Puns¥or, District Salesmen 50 Wanted fxein-t93353 a week at a Our union made suits and overcoats at peng (none higher)

pag 2 are America’s biggest valu We show $ latest nifty colors and styles { for men =< men. Only pure woo! fabrics 2 at? The overcoats —e satin lined. ts 4S, terri se spare timemen in some Ss coe towns. cite toc today toy —— blank gvet and free sampleof the world’s greatest clothi walues. Address F. S. HARVEY, Box 00, CHICAGO POPULAR SCIENCE MONTHLY September, 1935 "

Poisons in ‘‘Bootleg Booze’’ (Continued from page 42) public is disposed to resort to liquor of seemingly known and recent origin, under the impression that its local origin makes it safe and pure. “The almost inconceivable conditions under which moonshine is manufactured are responsible largely for its dangerous character. The moonshiner has no scru- ples regarding the fate of the ultimate consumers. He has no conception of the proper facilities with which to work or the time needed for producing a drinkable product. He lets his mash ferment in un- clean barrels, washtubs, and other similar receptacles, in dark, musty cellars, or in the open woods. Under such con@itions the development of wild yeasts or unwhole- some fermentations becomes inevitable. The vessels used become unspeakably filthy and ill-smelling after repeated use without cleaning, and the unprotected fermenting mixture attracts animal life of every description.” “The old-time distiller of the South would view with contempt the moon- shiner of ;today,” Linder added to the above. “This artist knew that he must discard the heads and tails of his distillation—the first and final ‘runs’ which passed through his still. — HE moonshiner of today uses heads, tails, and everything, and sells it as it stands. He refuses to discard anything that makes volurme. Poisons pay good profits. ‘Another danger lies in the haste with which the stuff is placed on the market. Whisky should be allowed to age. In pre-prohibition days the aging process covered from one to eight years, while the liquor rested in wooden barrels with the insides charred. “Sometimes an appearance of age is given by putting concentrated lye in the mash, to hasten fermentation. More than once government agents have found as high as 200 empty lye cans in a single place. Lye is very poisonous.” Extracts from reports of prohibition agents in various states shed considerable light on the almost unspeakable condi- tions under which liquor is manufactured. ‘“Moonshiners are dipping water from the North Canadian River,” reports Director Millard F. Meadows, of Okla- homa, “below the point at which the city sewage is dumped into the stream. The water is used in souring the mash.” ““Most of the whisky,” reports Director Daily of that made in Mississippi, “‘is made from rotten grain, black strap molasses, shorts, chops, and the like. Old cans, tea-kettles, coffee-pots, and oil barrels are used as cookers. The insides of these vessels are unspeakably filthy. All kinds of bugs gather on the stinking stuff and finally drown in the spirits.” Texas, Colorado, and Minnesota sent in similar reports. ! Near Homer, Ohio, raiders found a stock of whisky buried in stable manure, and the makers frankly stated that this was their method of aging their product. These are merely a few extracts from reports selected, at random from the government files. There are thousands of others. ‘

© This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. It BURNS the Smoke by mixing jt with a supply of super-heat- ed air (oxygen) over the fue] bed. That's why the CROWN save: SAVER is warranted to save at least 20% of your coal bill and often does much more, Successfully used for 10 years. We have just issued a detailed description of the Crown. If you are buying coal for con- sumption in a factory, store, residence, apartment building, school, church, theatre or greenhouse, write us today for proofs, Splendid sales proposition for live dis- tributors. Write—ask if your territory is open. CROWN FUEL SAVER CO. 19 N. 10th St. Richmond, Indiana Stop Using a Truss STUART’S PLAPAQ- PADS are different from the truss, being mechanico- chemico applicators made self-adhesive purposely to hold the distended muscles securely in_ place. No straps, buckles or spring attached—cannot slip, so cannot chafe or press against the pubic bone. Thousands have _ success- fully treated themselves at

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POPULAR SCIENCE MONTHLY A Pocket 66" Slide Rule How would you like to own a slide rule 66’’ long? Here is its equivalent in pocket form. The Otis King Patent Calculator has open spiral scales 66” long mounted on two metal tubes; yet when closed, it only measures 6 inches. - 1650 divisions are marked on each of the scales—roughly five times the number on a 10” slide rule,—and results accurate to 5 or 5 significant figures are easily read with absolute certainty. The instrument is practically in- destructible, and the scales, being mounted on an all-metal body, can- not warp as so frequently happens with the slide rule. And instead of a delicate glass cursor there is a tubular indicator, which is good for a life- time. Send for this useful little instru- ment at once; after you have used it you wouldn't be without it for 10 times its cost. Price $5, exclusive of duty, but including carriage direct to your door. CARBIC LIMITED 51, Holborn Viaduct, Lendon, Eng. Used in U. S. A. and Canada by Lick Observatory Columbia University Book Store U. S. Bureau of Mines, Washington University of Minnesota Brown University Delaware University U. S. Dept. of Agriculture Washington Fisheries Board Rockefeller Institute for Medical Re- search American Telephone & Telegraph Co. (Research Dept.) Harvard University Committee on Economic Researc Toronto University Saskatchewan University, etc. Ernest Pechin e conerviezore FTow to Win Success in Music Begin with the right instrument. This is the advice of the world’s foremostartists. Conn instruments, used and endorsed by the most successful players, are easier to play, most beautiful in tone, perfect in scale; reliable in action—possess many exclusive features, yet cost no more than others. Free Book by Sousa and nine other famous artists on “Success in Music,” helps you choose theinstrument for your tal- ent. Send now for your copy and details of Free Trial, Easy Pay- ments on any Conn instrument,, Cc. G. CONN, LTD. 932 Conn Bldg. Elkhart, Ind. INSTRUMENTS MANUFACTURERS WORLDS LARGEST How to Build a Wave Trap (Continued from page 74) causing most of the trouble. If, on the other hand, several stations are interfering with the one you want to receive, the parallel connection may prove more useful; for when the wave trap is hooked up in this fashion, it is tuned to the station you want to receive and signals from all stations on other waves are cut down in strength. It is desirable to mount the wave trap a foot or more from the receiver so that the magnetic coupling between the coils in the wave trap and the receiver will be at a minimum. Tuning the wave trap is very simple. When it is connected in series, the re- ceiver itself is tuned first to the wave of the interfering station, and then the dial on the wave trap is turned slowly until the signal disappears or is as weak as possible. Then the receiver is retuned to the wave of the desired station. Tuning the wave trap in the parallel connection is exactly the reverse. The desired station is first tuned in on the receiver and then the wave-trap dial is adjusted until the interfering signals are cut down as much as possible. 1 ial for the adjustment of coil A. If you have too many turns in this coil when the wave trap is used in the series connection, the wave trap will be too effective; that is, it will cut down the signal strength of the station you want to receive, besides eliminating the undesired one. In the parallel connection, on the other hand, too few turns make the wave trap very effective at the expense of the signal strength of the station you desire to receive, while a large number of turns in coil A reduces the effectiveness of the wave trap. Recent Publications Romance in Science, by Bessie I. Mil- ler, Ph.D., professor of mathematics in Rockford College. A collection of lec- tures on various scientific topics. Ancient Hunters and Their Modern Representatives, by W. J. Sollas, Sc.D., professor of Geology and Paleontology at Oxford University. Third edition of a popular work on archeology. Illus- trated. The Macmillan Company. The Story of Copper, by Watson Davis, C.E. An interesting, non-technical his- tory of the first of the useful metals. The Century Co. The Kinetic Theory of Gases, by Eugene Bloch. E. P. Dutton & Co. The Planning, Erection and Operation of Modern Open Hearth Steel Works, by Hubert Hermanns. D. Van Nostrand Company. The Elements of Machine Design, by S. J. Berard, Brown University, and E. O. Waters, Sheffield Scientific School (Yale). D. Van Nostrand Company. Space and Time, by Carl Benedicks, for- merly professor of physics at the Univer- sity of Stockholm. Discussion of the ideas of space and time as developed by Ein- stein from an experimental physicist’s standpoint. E. P. Dutton & Co. © This seal on a radio or tool advertisement signifies the approval of the INSTITUTE OF STANDARDS. See page 19. Anyone Can Play a Hohner Harmonica Not until you have learned to play a har. monica correctly will you appreciate what genuine tun and enjoyment is possible with this popular musicalinstrument. Andnow anyone can quickly learn to play with the aid of the Free Instruction Book. If you want to join the happy family of hay, monica enthusiasts, get a Hohner t and a copy of the Free. Instruction Boo! Thesimplechartsand pictures will help yoy to quickly master the scale; and once yoy can play the scale you will soon be playi your favorite melodies to the delight of yourself and friends. Ask your dealer for the Free Book today. If heis out of copies, write to M. Hohner, Inc., Dept. 182 NewYork City. : Leading dealers everywhere sell Hohner Harmonicas — 50c up, A S W/ Imperial STAY Kioor’ i) A composition material easily applied in plastic y form over practically any kind of floor. Laid Y4 about % inch thick. Imperial Floor does not crack, peel, or come loose from foundation. A continuous, fine grained, smooth. non-slipping surface. No crevices to gather grease, dirt, dust, disease germs 4 or moisture. 5 4A deal Floor for Kitchen, Pantry, Bath Room, Laundry, Porch, Garage Restaurant, Theater, Hotel. Factory, Office Building, Railroad Station, Hospital—wherever a beautiful substantial floor. is desired. Several practical colors. Full in- formation and sample FREE of your first and second choice of color. Imperial Floor Co., 394-396 Halstead St., Roch. ster,N.Y. yam A Success for 15 Years | "eS zee built — 44 styles, # ‘actory to Rider prices. [AV ry. express prepaid on 30 fa) Days Free Trial. Cash or easy payments. ires lamps, wheels and equipment Ay at half usual prices. Send no Riey- «& money. Write today for catalog, [Sry jal Factory Bicycle Prices from $21-80 us Lo marvelous offers. Takea W. A.C. Course ae in Applied Airplane Par ; Engineering. Many men earn $2000 to $10,000 a year. Big Free utfit of airplane parts. Write for Free catalog. WESTERN AIRPLANE CORPORATION *Yept. P-9 Monadnock Bik., Chieago, Il. Septe™ c a oO wo aa: nm otk ok oO Ot ee

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t ’ ial ember, 193 : oh ceiliet, 1925

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Here Are Correct Answers to Questions on Page 69 are forced up by atmospheric va Coban When you suck on the straw, Prat makes a partial vacuum in your mouth and in the upper part of the straw. Instantly the pressure of the air outside forces some of the liquid into your mouth, just as it does with any kind of a suction pump. 2. To prevent the breaking of their ear -ums. ‘The part of the ear back of the m communicates by means of a tube with the throat. If the mouth is open, the air wave from the fired gun goes in through the throat as well as into the ear. Its push against the outside of the drum will be neutralized by an equal push | against the inside. 3, Several kinds are known. The com- monest is made by dissolving a little co- palt chloride in water. This makes a light pink solution. Writing made with it is invisible so long as it is damp. When you heat it and dry it out, it turns blue andcanberead. Let it stand a while and it will take up moisture again from_the air, turn light pink and disappear. This

may be repeated many times. 4, Nearly 1,600,000 miles; about 18% miles a second. 5. The waves wear down the rocks and preak them up. The fine dust that is | produced is carried out to sea by the | water and is deposited on the bottom, but | the coarser particles stay on the beach | and make the sand. 6. Places in which the sun is cooler and | does not give out quite so much heat and | light. They are believed to be caused by great whirling storms in the surface layers of the sun. Some of them are large | enough for five or six spheres like the | earth to be dropped inside the whirling | center of the storm. 7. Hydrogen peroxide sets free an espe- cially active kind of oxygen. This active oxygen combines chemically with the colored substances in the hair and turns them into other compounds that are colorless or light yellow. 8. If there were any air inside the bulb the hot tungsten in the filament would combine with the oxygen of the air and burn up, just as a cotton thread would burn up in a hot furnace. 9. By means of a blanket of fat that almost entirely surrounds the body. It is this fat or blubber that provides much of the oil we get from whales. 10. Because it is only when it is hot that it emits the continual stream of electrons needed to operate the vacuum This ability of hot metallic wires to emit electrons in a vacuum is what scientists call “‘thermionic emission.” li. A kind of eucalyptus, or blue-gum, which grows in Australia. Individual trees of this species have been known to grow 400 feet tall. 12. This is another effect of the chemical discharged by your adrenal glands. This chemical makes all the tiny blood vessels in the skin and in the surface layers of the body contract so that most of the blood is Squeezed out of them. Of course, this has the effect of making your face seem whiter.

POPULAR SCIENCE MONTHLY 135 The Factory Back of Micadons Little Micadons—made with keenest care in a great factory. Made so accurately, and with such permanent capacity that they are accepted as the standard fixed condenser of radio all over the world and are found in 90 per cent of all radio sets. In buying fixed condensers be sure and ask for Micadons ’ Dubilier CONDENSER AND RADIO CORPORATION

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POPULAR SCIENCE MONTHLY rolt isnt q genuine 5199 unless” The familiar names WD-11, WD-12, UV-199, UV-200 and UV-201-A rightfully - belong to Radiotrons ‘only. To be sure of’ - quality, it is important to look carefully at the base of every tube. ‘you buy, to ‘see thar it” a. carries t tron and the RCA | “mark as proof that it is a genuine | Radio Corporation of America Chicago New York San Francisco adiotron AN RCA PRODUCT © This seal on a radio or tool ader*isement signifies the approval of the INSTITUTE OF STANDARDS. See page 19. Printed by Art Color Printing Co., Dunellen, N. J.