Popular Science Monthly 1923-09: Vol 103 Iss 3

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AUG 10 1923 Reg. US Pat Off A Marvel of the Speedway ( "%" ) to Bares Our Hidden Powers ('s °

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Radiola Portable Regenerative tuner; two tubes —Radiotron detector and one stage of audio amplification; ; all batteries and a pair of head & receivers.. $97.50 ’ Turn aknob—and tunein —mighty simple. Vernier attachment: for fine i tuning. Receives long distances with the headset, nearby sta- tions can be heard through a loud «speaker. ee. ete : “A j Send for the free ‘ booklet Radiolas from $25 to $350. Write for the booklet that tells all about ’em. Now for Camp with the new ortable Radiola! (Radiola IT) ERE’S a Radiola you can pick up and trot off with! Inacabinet that holds the head- set, the tubes, and all the batteries. Witha handle to carry it by. Think of taking your Radiola with you—tuning in almost anywhere, at any time, on half the country’s broadcast programs. Now for camp life with a Radiola! Music at the evening campfire. Baseball scores. Songs, news, talks, going with you wherever you go. Throw an insulated wire over a tree, and you are ready to listenin to far-away cities. Radiola II is a powerful receiver with two tubes. The secret of its smallness is the new Radiotron UV-199, that operates on ordinary little flash- light batteries! One thing. that will impress the family is the fine appearance of the set for home use, when you take off cover and handle. It’s a portable receiver—but, first’ of all, it’s a fine receiver, and a sensitive one. ” There's a. Radiola , far every pusse” at the nearest Radio or Electrical Store & a RADIO CORPORATION OF AMERICA Radio Corporation of America Dept. 2080. Address office nearest you. Please send me your free Radio Booklet. Sales Department District Sales Offices This symbol 233 Broadway 10 So. LaSalle Street 433 California Street eo 8 Baw shal New York Chicago, Illinois San Francisco, California Name : & Street Address City R. F. D. State REG. U. 9. PAT. OFF, — AES AE Troop No. 1 gets the scores at Camp Schnarr, Ossining, N.Y,

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‘Popular Seience Monthly 1 ~ Three new Victrola models The three new Victrola models illus- trated herewith incorporate Victrola musical quality in cabinets reflecting all the skill of the master designers of other generations—a perfect combination of art and utility with moderate cost, re- sulting from our unequalled facilities and long experience. Fully equipped with albums, Victrola No. 2 sound-box, new improved Victor ) tapering tone-arm and goose - neck | sound-box tube, full-floating amplifier, ) = speed indicator and the simple, reliable Victor motor. Built entirely in the Victor factories, which are the largest devoted entirely to the production of one musical product. In buying a talking-machine consider

Victrola No. 400 Mahogany, $250 Electric, $290 ‘Scores at ing,N.Y,

ot that you must choose the Victrola or - something you hope will do as well and Ir | remember that the Victrola—the stand- . me Walnut, $250." Eleccrte, $290 ard by which all are judged—costs no more. at . pau ee, <A Selected list of Victor Records

: ill ing Vi ality | . illustrating Victor qu ym ' h- Lucia—Sextet Galli-Curci, Egener, Caruso, | de Luca, Journet, Bada 95212 $3.50 wd Berceuse from Jocelyn McCormack and Kreisler 89106 = 2.00 -m Elegie—Melodie Caruso and Elman 89066 2.00 le Song of the Volga Boatmen Chaliapin 88663 1.75 2) Whispering Hope Gluck and Homer 87524 1.50 Ave Maria (Schubert) Heifetz 74563 = 1.75 Minuet in G (Paderewski) Paderewski 74533 = 11.75 Rid niaiineses be No. a10 sina tinal La Capinera se Wren) Galli-Curci 64792 + =1.25 i so Victor Symphony Orchestra 35717 = 1.25 National Emblem March U. S. Marine Band 18498 75 Lights Out March Arthur Pryor’s Band :

“oVictrola * iS MASTERS. VOICE” ) Look under the lid and on the labels for these Victor trade-marks. Victor Talking Machine Company, Camden,N.J.

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2 Popular Science Monthly SEPTEMBER, 1923; Vol. 103, No.3 25 cents a Copy; $2.50 a Year CIENCE moves its products rapidly from the laboratory into the home. Most of us remember when automobiles were called “‘horseless carriages,’ when airplanes were considered impractical, when radio was unknown. Yet today 11,000,000 Americans operate automobiles. We no longer marvel at the airplane. There are radio sets in three or four million homes. To an ever increasing degree we depend upon applied science in our daily lives. * * * N PAGE 63 of this issue, Jack Binns, our radio editor, tells simply and graphically of new hook-ups, understanding of which, here- tofore, has been confined largely to a little circle of technicists. Another article of absorbing interest to.the man who knows the inspiration of the phrase, “do it yourself,” is that of Victor H. Todd on mending household electric heating apparatus, page 67. Harold F. Blanchard, noted automobile engineer, in a story filled with hints for the motorist, page 71, points out how to get the most for your money when you buy a car. Such articles, in this day of applied science, interpret science in terms that are personal to all of us. * * * SCIENCE has captured and bottled insulin, a remedy for diabetes. The dramatic story of this achievement, one of the most far reaching in medical annals, is told on page 23. One by one the terrible maladies afflicting the uman race are being conquered. Cancer may be next. A 300,000-volt X-ray machine, now being tested in Philadelphia, bombards the dis- eased tissues with minute particles thrown from radium at a tremendous speed. It may solve the cancer problem. * * * A NEW fire breaks out in some American home every four minutes. And _ with almost every forward a POPULAR SCIENCE MONTHLY Most Wonderfully Illustrated Magazine in the World Published in New York City at 225 West Thirty-ninth Street Kenlon, of the New York City Fire Department, on page 36 and read how modern fire fighters call science to their aid. Chief Kenlon believes that scientific fire prevention can add years to the life of the average structure. “Modern fire fighting is a scientific profession, comparable with no other more than to that of medicine,” he says. * * * [N AN arresting story on page 33, Raymond J. Brown points out the ever increasing dangers from poisonous automobile gases. It is suggested that an upward turned exhaust releas- ing the fumes above the top of the car may help temporarily. But as the number of cars on our streets increases, such a plan would not afford permanent relief. Scientific ingenuity may be depended upon, however, to find a better solu- tion to the problem. * * * PERHAPS the most constantly recurring question in science today is that of evolu- tion. In this month’s chapter of the “Story of Man and His World,” page 26, Dr. E. E. Free presents the “proofs of evolution.” In a fasci- nating way he unravels the world riddle of exis- tence. He bases his reasoning upon centuries of laboriously gathered scientific facts. Whether or not you agree with Doctor Free, you will find his story this month absorbingly interesting. * * * ILL the sun ever fail us? Robert E. Martin asks this question in a stimulat- ing article on page 41. Remember that all our fuel—all our food—everything in life—we get from the sun. Some day chemists may find a way to produce artificial food without the help of the sun. Thus far, however, our bodies live by digesting sunbeams. * %* * DISTINCTIVE article is that of Dr. James J. Walsh on “Auto - Suggestion,” page 58. Doctor Walsh See Table of Contents on page 118 _ tells vividly how men may harness their minds step in science and in- vention come new fire hazards. The motion picture brought inflam- mable film; the auto- mobile brought gaso- Issued monthly. Single copy, 2 Office Department, Cana told by Chief John PopuLAR SCIENCE MONTHLY cents. Yearly subscription to United States, its possessions, and Canada, $2.50; foreign countries, $3. . Entered as second-class matter Dec. 28, 1918, at the Post Office at New York under the act of March 3, 1879. Entered as second-class matter at the Post fod Printed in U.S. A, Copyright, 1923, by the Modern Publishing Co. The orittinte of this magazine must not be reprinted without permission. : Fisher, vesitent ; R. C. Wilson, line. Turn to the story Bake ys RAS and make them work for them. He points out the connection be- tween the satisfaction that comes with the knowledge of a good Vice-President job well done, and suc- cess. m Ee A Peed KK “ST AA. Da 1

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e t) a ® ED © © EE © © SEED © 0 GEE © @ CEE « _ | | | | | | | | Popular Science Monthly ERROR TE Te ERNST TY Fo EET FOF Ee -¢ Gf SEE @ © CEE © o ECE ~ © SEER © 0 GEER © © THEY SAY— Brief Bits of Timely Comment BA oo the Sciences of the Hows DR. SIMON FLEXNER, director Rockefeller Institute of Medical Research, discussing the $150,000 gift of John D. Rockefeller, Jr.,to 15 hospitals in theUnited States and Canada to promote the use of insulin in the treatment of diabetes, as described on page 23 of this issue: “Insulin is one of the greatest discoveries of modern times. There is no question about its effi- ciency. Its use, of course, is supplemented by the usual regard for special diet, but it adds enor- mously to simplification of present methods. “Insulin patients, can be trained to direct their own after-care, and treat themselves.” ALFRED B. HITCH- ENS, PH.D., Director of the Research Laboratory of the Ansco Company, Binghamton, N. Y., who has discovered a means of diagnosing diseases by a special application of pho- tography: “Photography can be of the greatest help in establishing and portray- ing unique disease char- acteristics. It is well known that with proper selective color filters and suitable color sensitized photographic emulsions, details of color and struc- ture can be detected be- yond the range of the microscope. “I have found that there is a definite photo- organic change for specific diseases. -By means of specially prepared selec- tive filters and specially sensitized photographic emulsions, these changes ‘dan be differentiated pho- tographically.” Alfred B. Hitchens, Ph.D., F.R.P.S., F.R.M.S., F.C.S. EDOUARD BRANLEY, known as France’s “father of wireless,” who at the age of 77 an- nounces that he has succeeded in transmitting = a Be — ands CALVIN COOLIDGE, Vice President of the United States: “‘This era has come to be recognized as the scientific age. On this side of. life the world is vividly alive and thoroughly interested. It is making larger and larger demands of the schools, of the press, and of every other avenue that provides technical skill and scientific knowledge. “Yet when success in this direction is not secured, or, being secured, it fails somehow to satisfy, there is a tendency to begin to criticize our institutions and the standards of society as though they were in some way to blame. Some- times this goes so far as to advocate a complete change in the attitude of the Government toward property rights. More generally this takes the form of some proposal for extended government control. “Individual initiative in the long run is a firmer reliance than bureaucratic supervision.. We do not need more gov- ernment; we need more culture. We do not need more laws; we need more religion.” by wireless not only a luminous point but a circle of light, thereby proving that vision by wireless might become possible at almost un- limited distances: “It probably will not be long before people are see- ing over wireless, as Ed- ouard Bélin suggests. The- oretically it is a sound idea. We have shown that high frequency oscil- lations of ether waves carry sound vibrations, and Bélin’s results so far indicate that the original idea might be applied to other waves. Perhaps we may be able to carry heat by wireless some day— who knows? ““Of course there are too many new and great diffi- culties to overcome to pre- dict just when new Edouard Branley, France’s “father of wireless,” in his study ee ee ieee ca achievements may be ex- pected.”

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SEPTEMBER, 1923 POPULAR SCIENCE MONTHLY SUMNER N. BLOSSOM, Editor Insulin—A Miracle of Science How a Young Laboratory Assistant Won World Fame by Discovering Serum that Offers Relief to Millions of Diabetes Sufferers By Donald Harris ROM six hospitals in the United States a few weeks ago came some news that electrified the scien- tific world. A serum de- rived from the entrails of animals, given to the hos- pitals for clinical test of its efficacy as a treatment for diabetes, had proved so extraordinarily success- ful in administration to many hundred patients, that the physicians who conducted the tests as- serted without qualifica- tion that it appeared to be a'sure method of control- ling the disease. What “Insulin” Means The new serum is in- sulin, a name derived from the Latin word meaning “island.” This name was applied because the par- ticular groups of intestinal cells from which the serum is extracted are known in medicine as the “Islands of Langerhans.” Since the first announce- ment of the successful i : Vg a. } : ss a (he GG Ba Hk ne wt eo} discoverer’s work was ac- complished in the incom- plete home laboratory of a young Toronto doctor, a school friend, who per- mitted him the use of his home and _ equipment merely because he, the owner, was going away on a vacation and had no use for them. The discoverer of in- sulin is Dr. Frederick Grant Banting. Probably there is no better illustra- tion of the general atti- tude of the medical pro- fession toward him and his discovery than the recent comment of Doctor Flex- ner: Where Experts Failed “No one had ever heard of him. In fact, there was no reason why any- one should have heard of him. “This young doctor didn’t know much about diabetes. Quite by chance he discovered how to get insulin and use it as a cure. At Toronto he proved the efficacy of his treatment. We experienced physicians who had so much material as Injecting insulin into the arm of a diabetes sufferer in the insulin clinic of the Montefiore Hospital, New York City. Dr. Benjamin Duborsky is shown administering the new serum and so much scientific background to help us find a cure for diabetes, failed. We feel like kicking our- selves. tests of insulin, eminent medical men have been almost a unit in declaring that through its general use probably will be tere sounded the death knell of diabetes, a disease which until now has resisted the best efforts of medical science. Dr. Simon Flexner, director of the Rocke- feller Institute for Medical Research, has said that insulin promises to prove “‘one of the great medical contributions to the world.” Dr. A. I. Ringer, in charge of the test of insulin at the Montefiore Hospital in New York, stated unequivocally that “insulin is undoubtedly one of the greatest discoveries of the age,” and that, now that it has been given to the world, ‘“‘no person should die of diabetes.” : Dr. Nellis B. Foster, writing in the “New York Medical Journal,” declared, “I think it is safe to say that could one start with insulin before operation, one could be reasonably sure that the patient would not die of diabetes.” Other medical authorities expressed their indorsement of the new serum with equal enthusiasm, and John D. Rockefeller, Jr., only a few weeks ago contributed $150,000 to permit 15 hospitals in the United States to introduce the use of insulin in their clinics. Probably the most amazing and dramatic feature of this remarkable discovery is the personality of its discoverer. The man who gave insulin to mankind was no famous medical authority, nor was he even a recog- nized scientist, trained in the intricacies of research, fortified by exhaustive knowledge of medical lore, and possessing extraordi- naryequipment in laboratory and materials. Instead,» he was an obscure - Canadian doctor of 31, less than six years out of medi- cal college, a farmer’s son, who had accepted with pride a humble position as a labora- tory assistant in a Canadian university when he returned wounded from war ser- vice only three years ago. Moreover, the most valuable part of the “The world is enor- mously richer today as a result of Doctor Banting’s discovery of insulin. It seems to me that mankind never again will be in the grip of this disease as it has been for so long. There is still a bit of danger in its use, but some day we shall all know just how to ad- minister it. .Then all the world, every ham- let of it, will appreciate the benefits.” In speaking of “chance” as a factor in Doctor Banting’s discovery, Doctor Flex- ner had no intention of belittling either the discovery or the discoverer. The truth is that in what Doctor Banting has accom- plished, chance played a prominent part, and no one is more ready to admit the fact than he. Diabetes is caused by the failure of the Islands of Langerhans properly to perform their functions. In the normal man these ‘islands’ secrete insulin—the same insulin which now is taken from animals to supply a means of fighting diabetes. 23

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2A Carbohydrates—loods of a starchy sort —are converted into sugar, which is ab- sorbed by the intestines. Part of the sugar is carried to the liver, where it is stored as glycogen, or animal starch. The re- mainder is carried by the blood to the muscles and other tissues, where some of it is oxidized and some stored as glycogen. Insulin secreted by the normal man passes directly into the blood, there combining chemically with the sugar substances formed from food to sup- ply the body with elements necessary to the health. In diabetes, the in- sulin fails to perform its chemical action on the sugar substances. This . causes them to circulate in large quantities through the blood and to be lost in excretions. The body, in consequence, is deprived of an im- portant source of energy. Among the symptoms of the disease are vora- cious appetite and abnormal presence of sugar in the blood and certain . bodily excretions. What Causes Diabetes The medical profession long had -known that the removal from an animal of the Islands of* Langerhans resulted in symptoms of diabetes. Also, marked destructive changes in the “islands” were noted in the majority of patients who suffered from diabetes. The conclusion, of course, was that a derangement of the secretions from the “islands” was the cause of the disease. Investigators had arrived at the belief that extracts of the secretions from the “islands” obtained from animals might supply a serum, which, by supplying to diabetics the in- sulin which nature was failing to produce, would form an effective treatment for the disease. Langerhans, the German physician for whom the “‘islands’ are named, and others had expressed this opinion in treatises, but attempts to obtain pure insulin proved futile, since it was de- stroyed invariably by the powerful diges- tive ferments present in the extracts which were made. Dr. Banting Begins Research Work In November, 1920, Doctor Banting, having chanced upon Langerhans’s work on the subject of diabetes, became interested in the possibility of developing the serum, and began experimenting at the labora- tories of Western University, where he had been a laboratory assistant for a few months. He discovered this work to be so engrossing that he applied for a two months’ leave of ab- sence and set up a laboratory at the home of Dr. F. W. Hipwell in Toronto. Doctor Hipwell was a school and college friend, who was leav- ing the city for a vacation. The two months’ leave was extended to three, and at the end of that time Doctor Banting resigned from the university, for his experi- ments were progressing with encouraging success. In attempts to extract pure insulin from the intestinal tracts of animals, previous experimenters had shown that by tying up the ducts from whence came the digestive juices, degeneration occurred much more rapidly in the juices than in the Popular Science Monthly Islands of Langerhans. After many months of work, Doctor Banting con- ceived the idea that if an extract were pre- pared from the intestinal tissue remaining, some time after the ducts had been tied, it should contain insulin because there would : Dr. Frederick Geoint Rantioe Y HIS discovery of insulin, a serum used with amazing success in the treatment of diabetes, Dr. Frederick Grant Banting, 3! years old, son of a farmer and a laboratory assistant in a ian uni- versity, suddenly finds himself lifted from obscurity to worldwide fame. John D. Rockefeller, Jr., recently do- nated $150,000 to permit 15 hospitals in the United States to introduce insulin. The Canadian Government has granted Doctor Banting an annuity of $7500 a year for life. Ontario Province has appropri- ated $10,000 a year to found a department of research at Toronto University, to go to Doctor Banting as its head. not be enough of the digestive ferments to destroy’ xt. In 1921 his experiments in this line proved successful; he obtained the serum Two vials of insulin, administered by injection into the patient’s arm he sought in a comparatively pure state and devised methods of refining it further, re. moving from it substances ‘that rendereq it unsuitable for repeated injection in man, By this time his experiments had reached a stage that led the authorities of the University of Toronto to permit him to pursue his work in the famous Connaught Laboratories. It wag from there, after several months’ jn. tensive work to determine the effect of insulin on normal and diabetic animals, that the announcement wag made that the Banting serum wag ready to be offered to the medica} profession for clinical test. In hig work at the university, Doctor Bant- ing was assisted by Dr. J. J. Me. Leod, Dr. C. H. Best, and others. Successful Tests in United States The results of the tests of insulin conducted in six hospitals in the United States; have been entirely successful. Previous to the introduc- tion of insulin, the accepted treat- ment for diabetes was dietetic, limiting the quantities of starches and sugar taken in food. This method of treatment was unsatisfactory, since the inadequate diet resulted in great loss of strength and energy, and since lapses from the severity of the pre- scribed diet resulted in recurrence of the diabetic symptoms. Using insulin, physicians now are able to permit their patients a strength- sustaining diet during treatment. The serum, which -usually is’ injected in the arm, restores to the body its normal power of transforming starches, sugars, fats, and similar food into the chemical constituents necessary for health. Many of the patients whom the clinical directors pronounced cured of diabetes by insulin had been in a-diabetic coma from which only a handful of sufferers ever had emerged previously. Five who had been in this last stage of the disease were treated and discharged at the Montefiore Hospital alone, Robert Lansing Is Aided by Insulin Prominent among those whom insulin has helped is Robert Lansing, former Secretary of State, who had been a sufferer from diabetes for years. Recently he stated that, after six weeks’ treatment with insulin, he was well on the road to recovery. Just how important. Doctor Banting’s discovery is to the health of the nation is shown by mortality statistics recently pub- lished by the United States Census Bureau. These reveal that for 20 years the number of deaths from diabetes has been increasing steadily in the United States with a really startling increase since 1919. In New York State the rate of mor- tality from diabetés is highest—22 in 100,000. New Jersey, Pennsylvania, and Ohio also show very high rates, while in the West and South, deaths from this disease are comparatively few. The variations are due, not to differences in climate, it has been ex- plained, but to the recognized varying susceptibility to diabetes of different classes of the population. Thus, old persons are more prone to contract the dis- ease than the young; white persons are more susceptible than colored; women are more susceptible than men. Among the white (Turn to page 112) —_ nah at bee fe OA

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tate and ther, re. rendered in man, reached of the mit him famous It wag iths’ in. 1€ effect. diabetic ent wag uM Wag medical In his r Bant- J. Me. ers. States insulin in the ontirely troduc- treat- ietetic, nes and thod of » Since n great d since 1e pre- ance of ow are ength- The in the 10rmal ugars, emical linical tes by : from er had 1 been were tefiore sulin nsulin ormer fferer y he ‘ment ad to ting’s ion is pub- reau. 3 the 3 has nited rease mor- 22 in ‘ania, rates, eaths ively ot to nN ex- rying erent » old 2 dis- more more white Popular Science Monthly New Airplane Conquers Fire Peril | GRAY monoplane —the A-6455— soared gracefully over the Glenn L. Martin flying field, Cleveland, Ohio. Up, up it went, while a little group of spectators on the ground watched with nervous expectancy. Suddenly there was a burst of flame from the engine. The whole hood seemed in flames. A second tongue of fire shot out from under the wings where the gasoline tanks nested. ‘hen, while naval ex- |. perts and aviators below ~ \ : pt REE et wit aN Se tee Below is the mush- room - shaped, releas- able gas tank. In case of fire, a lever con- trolled by the. pilot cuts a soft metal gas line and releases catches that hold the tank to the airplane held their breath in sus- pen3e,the shooting flames suddenly were snuffed out as if by magic; the mushroom-shaped gas tanks hurtled from the wings, blazing, but harmless, to the ground, and the plane volplaned safely to earth. The pilot stepped out. One of the most ruthless enemies to man’s conquest. of the air—fire—had been defeated. Emergency Levers De the Trick To accomplish this amazing. feat, the aviator, after deliberately.setting fire to the gas tank, and to the engine, simply had pulled two levers. The first lever floodea the blazing engine -with. fire-extinguishing fluid; the other cut the soft metal tubes from the gas tanks to the engine. At the same time, this second lever released trip catches that held the tanks under the air- plane wings, and the tanks fell blazing. to the ground. . How to safeguard the airplane from the appalling fires that during the war took heavy toll of the lives of aviators, is a sub- ject upon which airplane makers have racked their brains and have spent much time and money. Until the recent success- ful test described above, all attempts at a solution had failed. But now United States naval officials, in conjunction with the Glenn Martin Company, believe they have perfected a ‘thoroughly satisfactory safe- guard. The first plane to be equipped with the Dropping a flaming gasoline-tank from the: wing of, the: navy plane A-6455 during fire safety test above the L. Martin flying field, Cleveland, Ohio. tank clears the. landing gear. Note how*the The plane ‘landed ee new devices is a navy all-metal pita toni for spotting gunfire. Every ‘partiof this ma- chine, except the linen wing covering, is built of duralumin, the aluminum alloy that is almost-as light as aluminum and_ nearly as strong as steel. The two gasoline tanks are of mushroom shape and are set one into each wing on the under side. The fire-extinguishing device is a spe - cially: built pressure extinguisher, mounted under the engine hood, where most. of the airplane fires start. The enormously rapid combustion of. gasoline that makes the power also makes heat, and sometimes the engine backfires. Either of these causes may ignite the oil, causing a disastrous fire, often resulting in the death of the pilot. In the new navy plane, the pilot simply ALL METAL FRAME UNDER WING GAS TANK SLUNG \ i Ga es AN 5 OUTSIDE OF LANDING SOFT METAL GAS LINE TO TANK CUT IN CASE GF EXTINGUISHER GEAR The all-duralumin frame of the fireproof plane, showing position of the releasable gas tank beneath the wing, and the fire extinguisher-in the hood. Incase of fire, valve in the extinguisher and floods the with extinguishing fluid through distributing tubes, as shown in inset pulls a knob mounted on the dash in the’ cockpit. This knob, by means of a wire, opens the extinguisher vaive., Distributing tubes carry the fluid’ to alt parts of the en- giné, spraying them thoroughly and quickly putting out the fire. How the Tank Is Released If by chance the fire should spread to the gas tank, the pilot pulls another lever that cuts the soft metal tubes leading from the tank to the engine, at the same time releas- ing catches that hold the tank in the wing. The tank falls clear of the landing gear, blazing but harmless, and the pilot'is able to'make a safe landing. The linen covering for the wings is care- fully fireproofed with chemicals, to prevent it from catching fire during the time it takes the pilot to release the tanks. In tests, aviators, having set both engine and gas tanks afire, were able to land with practically no damage to the plane and with no peril to themselves. Next—The Air‘‘Pullman’’ HE remarkable inventions described above sweep away one of the most formidable barriers to successful commercial air transportation—fire: We are but a step from the day when we shall speed across country in luxurious winged sleeping’ cars, without fear of accident. Just such an air sleeping car —one that can be adapted to travel either on rails or in the sky—aeronautic engineers even now are designing. It will be described in an early: issue of POPULAR SCIENCE MONTHLY, with fascinating and authorita- tive illustrations.

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Thomas H. Huxley, great evolutionist and an early contributor to POPULAR SCIENCE MONTHLY tists in the world believe in the theory of evolution. The vast majority of educated people believe in it also. Only a few weeks ago a group of leaders of American thought in science, religion, and public affairs issued a public state- ment affirming their conviction that evolution is true and that it does not conflict in any essentials with the Christian religion. To convince this great body of serious and intelligent opinion must have required strong proofs. We must pause now in our story for a recapitulation of these proofs. What Is Evolution? Let us consider, first of all, how the theory of evolution came to be formulated and just what this theory means. It is a matter of common observa- tion that there exist in the world a great many different kinds of living creatures. You can see perhaps a hundred different kinds of plants and half a hundred different kinds of birds, worms, insects, and other animals on an hour’s walk in the country anywhere in the world. The students of natural history estimate that there are now living in the world more than 1,000,000 kinds of animals (including, of course, worms, insects, fish, shell- fish, and all the rest) and more than 2,000,000 kinds of plants. Life in 5,000,000 Shapes In the rocks that were deposited during previous geologic periods we find the relics of still other kinds of living creatures, now extinct; for example, the great reptiles that we described in previous chapters. Altogether, the different kinds of living creatures, plant and animal, that do live or have lived on our planet, must total well over 5,000,- 000. A total of 50,000,000 is even more probable. How did this tremendous number of different creatures come into ex- istence? This question has been asked ever since the time of the ancient Greek philosophers, nearly 3000 years ago. There have been suggested, in essentials, only two answers. One is the answer of special creation. The other is the answer of evolution. According to the idea of special Pitre the w all the scien- cen ICE AGE] ONE o . Ko4 MILLION YEARS } SKULL OF THE APE-MAN OF § JAVA, ABOVE, AND OF THE = SABER-TOOTH TIGER, FIERCES i OF THE GREAT EXTINCT CAT AGE OF 1-750 MILLION YEARS Popular Science Monthly The Proofs of Evolution Seventh Article in the Fascinating Series, “The Story of Man and His World” By E. E. Free, Ph.D. “ABOVE, AN AMMONITE ANCESTOR OF THE CHAMBERED NAUTILUS. BELOW, ONE OF THE RAREST FOSSIL RELICS THE LOWER JAW OF A FIRST TINY MAMMAL, RELICS OF THE AMPHIBIAN AGE. BELOW IS THE SKULL AND BACKBONE OF A WATER LIZARD WHO LIVED IN TEXAS? 4 f3 A GRAPTO! LITE ANC -ESTOR MILLION YEARS AGO.” oe ~ PROTEROZOIC ERA T z PLEIS CENE PERIOD TERTIARY, ERA MESOZOIC ERA PALEOZOIC ERA i * Geologic chart showing how fossils occur in the rocks aa ll ee | er | CharlesR. Darwin, fa- mous natural- ist and the father of the modern theory of evolution creation, each one of these millions of plants and animals was created suddenly and complete at some time in the history of the world, each by a special supernatural act. The Evolutionists’ Theory The alternative idea is that one kind of creature can change into another kind, and this into a third kind, andsoon. Some original kind of wildcat, for example, is thought to have changed, gradually and through many generations, one branch into tigers, another branch into lions, a third into the various varieties of domestic cat, other branches into the other existing and extinct kinds of catlike creatures. Similarly, according to this idea, man himself, as we have told in pre- vious chapters, is one of the many branches that have developed from the little tree-living, somewhat cat- like creature called lemur that lived fifty or sixty million years ago. Yhis is the idea of change, of evo- lution. The theory of evolution may be defined as the idea that cer- tain kinds of creatures,. plant or animal, can change into other kinds. Where Life Began If this be true, it is evident that all the millions of kinds of creatures, living and dead, that we krow to have existed may have originated by change and divergence out of a few kinds in the beginning, or, as most evolutionists believe, out of one original kind, namely the one- celled living slime specks of the primeval sea. Evolution, then, is one way of explaining why there are so many different kinds of creatures. Man, according to the evolution- ists, is not a finished device, made all at once out of the necessary raw materials as a sculptor makes an image out of clay. Man is the prod- uct of many changes occurring one after another, as the seed of an apple will change in the course of years first into a plantlet, then into a slim sapling, and finally into a spreading and fruit-laden tree. ' Defenders of this explanation of the origin of man must produce proofs—proofs that man has de- veloped, age by age, out of a long line, of animal ancestors, some of them wormlike, some fishlike, some reptilelike, some monkeylike. Such proofs can be produced. ha’ un roc an for

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ns od ne ch ne rd 1d ht 1d ne ch us er 1d a, ly m t- ad yn Tr or iS; ‘breeding, thus duplicating The more important ones that have been offered can be stated under five heads. First, the fossils found in the rocks enable us to trace the ac- tual history of life and its evolu- tion. Second, inside the human body there are numerous organs and parts of organs now useless to us, but which were developed . for and used by one or more of our animal ancestors. Third, many of the workings of the human body also are in- herited, quite obviously, from animals that preceded us. Fourth, the body of a develop- ing child, before birth, passes — through stages that recall the bodies of lower animals—worms, fish, reptiles, and others. Fifth, new kinds of animals and plants actually have been produced artificially by evolution experimentally. Some of these proofs of evolution have been implied in previous chapters. We have discussed, for example, the recovered bones of fossil-men, bones that are clearly intermediate in shape and character ‘be- tween the bones of modern men and of the apes. These are the links, no longer “miss- ‘ing,”’ that tie our bodies to the bodies of the beasts. Age-Old Rocks Submit Evidence We have seen,-also, that the whole great assemblage of fossils fourfd in the rocks of the earth show a progressive rise of life from the first rocks to the latest ones. In the deepest and earliest rocks we find traces only of the simplest creatures, little one-celled bits of living jelly like the first slime specks or like the microscopic crea- tures that still live in the water of roadside ditches. . In the upper rocks, of later and later age, we find the life forms growing steadily more complicated and diverse. We can trace by actual fossils dug out from these rocks the main stages in the upward path of life. We can see how the most primitive and simplest forms of life developed into wormlike things, and these into fishes, and these into reptiles, and so on upward to man. But strong as is this proof of evolution from the fossils, it is no stronger than the second proof, from the body of man itself. The human body, as we said in a pre- vious chapter, is a Popular Science Monthly 27 value in it was absorbed. The living museum of the past. Let us consider, for ex- ample, that annoying little organ, the appendix, The appendix is more . valuable nowadays to the surgeons his get paid to cut it out than it is to its original possessors. So far as we know, it has no use nor function in the modern human body. But it is an important proof of evo- lution. It is a vestige of an extra stomach which we used to have and which has dis- appeared. The animal ancestors of man were at one time eaters (in part) of roots and grass and the bark of trees and of similar materials, which are, for us, almost totally indigesti- ble. The ordinary digestive juices do not attack such woody substances. There exist, however, certain bacteria that do attack them. When chewed-up bark, for instance, has been acted on by these bacteria, it be- comes more or less softened and digestible, just as meat becomes less tough when it is allowed to hang., Therefore, our animal ancestors, who had to eat stuff like this, set aside a part of their digestive system in which these wood-softening bacteria could live. The woody part of the food was held there, in a kind of sack or supplementary stomach, for a few hours or days until the bacteria could soften it. Then the food ORANG-UTAN CHIMPANZEE Ponnilar Seianea Monthix Bones buried in the flank of the porpoise (indicated by arrow) are relics of legs used by this creature’s an- cestors millions of years ago when they ~— on shore grass-eating animals, such as the cow and horse, still have this extra stomach and use it just as our ancestors did. Exit Man’s Second Stomach With the passage of millions of years and with a change of diet for the animals in the human line, the need of this wood- digesting stomach disappeared. The stomach shrank. Now it is represented, in man, only by the appendix, a little tube an inch or two long and about the thickness of a lead pencil, attached at one end to the intestine. It has be- come so troublesome to us, so liable to disease and inflamma- tion, merely because it has lost its proper job. Like all idlers, it is prone to disturbance and dis- content. There are nearly 200 similar vestige structures like the ap- pendix, structures that have at present no important value to the body, but that were neces- sary to some one of our animal ancestors. One of them is the’ pineal gland in the brain of modern men, ‘an organ that is the vestige of a third eye that some of the ancient reptiles had on the top of the head. There is still living, in New Zealand a rep- tile, one of the “living fossils’’ mentioned in a previous chapter, that has on top of its head a structure determinably an eye, though not one that can be used to see with. How can we explain this living reptile? How can we explain the vestige of another eye inside our own brains and the brains of other modern mammals except by inheri- tance from those extinct reptilian ancestors of ours who had this third eye and whose fossil skulls, showing the telltale third eye- hole, we have,found in the rocks? There is space to mention only a few of the other vestige organs. Man’s fossil an- cestors had 13 ribs; man has only 12. But sometimes a man is born with 13. Some people still possess the muscles that used to be needed to move the ani- mal ears and such people can amuse the children by _wriggling their ears GORILLA MAN A glance at the skeietons of man and the apes shows how similar they are to each other

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28 Popular Science Monthly Relics of Evolution in Man’s Body THE THIRD EVELID OF BIRDS SURVIVES AS A LITTLE MEMBRANE IN THE CORNER OF THE EVE — PINEAL GLAND, , RELIC OFA THIRD EYE IN THE BRAIN FINGER NAILS, RELICS OF THE CLAWS OF MUSCLES THAT TWITCH Ae ANIMALS ~ THE EARSAND THE SCALP, RELICS OF “J SIMILAR. a ONES IN ANIMALS # THE MUSCLES OF FACIAL EXPRESSION SOLE SURVIVORS OF THE SKIN MUSCLES OF ANIMALS - € j DARWINS POINT ¥ ON EAR ~- THE EUSTACHIA TUBE, RELIC HAIR LOST MOSTLY FROM OF THE GILLS BACK AND SHOULDERS OF FISHES - WHERE COVERING BY CLOTHING JS MORE PERFECT - THE APPENDIX, RELIC OF EXTRA STOMACH OF WOOD- EATING ANIMALS~ BONES OF TAIL BURIED IN THE BACK - MORE HAIR RETAINED ON THE LEGS, WHERE THE PROTECTION BY CLOTHING IS LESS PERFECT ~ TOES STILL RETAIN SOME POWER OF GRASPING, THINGS LIKE FINGERS- BONES OF THE ARCH OF THE FOOT STILL SHOW SAME STRUCTURE AS BONES OF THE HAND ~- Above are indicated some of the organs developed by man’s animal ancestors for their use millions of years ago, vestiges of which survive in modern man backward and forward. In the corner of the human eye there is a little fold of skin that is a remnant of the third eyelid of the ancient reptiles, a structure that still per- sists in our distant cousins, the birds. An occasional person has on the top edge of his ear a little sharp point, known as Darwin’s point, that is a vestige of the pointed ear ve the cats and insect-eaters. Whales Once Had Legs Whales and porpoises have no legs— visibly—but underneath the skin, buried in the flesh of their sides, are the shrunken vestiges of leg bones, telltale relics of the fact—which we know also from the fossils— that the remote ancestors of whales and porpoises were land dwellers and had legs. The third proof of evolution is the proof from the actions of the human body, from - the way it works. The habits of the body, its chemical and physical machinery, origi- nated, like its anatomical structure, far back in the forgotten past. Let us take as an example the chemical (and other) changes that take place in the body unconsciously and involuntarily whenever we are angry or afraid. Two of the so-called ductless glands are named by scientists the adrenal glands. They are little lumps of tissue, each about the size of half a walnut, placed one on top of each kidney. These adrenal glands have, among other functions, the duty of prepar- ing the body for a fight. Whenever you are angry or afraid’, whenever you realize, that is, that you may soon have a fight (or a flight) on your hands, an emergency nerve message goes to these adrenal glands. The glands dischargedmmediately into the blood some of a certain chemical that they manu- facture. When the Adrenals Get Busy This chemical has profound effects on the body, especially on the blood and the heart. It quickens the circulation and at the same time it causes the size of certain blood ves- sels to change so that less blood goes to the internal organs, which you do not need while fighting, while more blood goes to the brain and muscles that may have to work harder and more accurately than usual. The little blood vessels in the skin and in the surface muscles are narrowed down so that bleeding from a wound will. be less severe. All these changes are automatic. Every fighting resource of your body is mobilized at the signal of this gland chemical in your - blood. Now, among the effects of this mobilizing chemical on the body, there is one. that seems very curious. As soon as there is some of the chemical in the blood, even when it is injected artificially by a hypo- dermic, all the tiny muscles buried in the skin and attached to the hair cells contract so that the hair cells are pulled up on end, producing that peculiar roughened condi- tion of the skin that we describe as “‘goose- flesh.’ In the scalp the hairs actually do stand up straight, a well-known effect of severe fright. Why should this be? The raising of gooseflesh pimples on the skin or of the hair on the head is of no perceptible value as a fighting weapon. No. For us it is not. But we have not always been “us.” , Once, a few million years ago, we were little catlike creatures skipping about in the trees. These crea- tures had thick fur. When they were frightened, they ruffled it up, doubtless, (Turn to page 98) a ee I = .

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er of skin f the per- of his win’s ar of on the heart. > same d ves- to the ; need to the ) work usual. and in wn so »e less Every bilized n your ilizing e. that here is » even hypo- in the mntract yn end, condi- ‘goose- ally do Tect of jing of of the e value uve not million eatures e crea- y were ubtless, Popular Science Monthly 29 New Steam Car Starts in 30 Seconds of the boiler. States Bureau of Mines continu- ally reminding us we are consum- ing our petroleum resourees at an excessive rate and that we can count on this source of power for the automobile for only a comparatively few years, engineers and in- ventors have been urged to develop the ~ steam car to a greater degree of perfection. After 12 years of steady work, Abner Doble, of San Francisco, has constructed a steam automobile possessing improvements that mark it as a distinct forward step in the evolution of efficient steam power plants. Drawbacks of the Steam Car The difficulties with most steam automo- biles has been the time required to get up steam for a start and their complexity of operation as compared with gasoline cars. They have had more parts than the gas car, and their engines have possessed more vul- nerable points. In addition, since so many more factors had to be taken into consider- ation, it has been deemed desirable to install automatic controls. This feature has introduced: other ways in which the engine may go wrong, adding to the owner’s difficulties in keeping ‘his car in first class condition. In most steam cars that have been manufactured, boilers are inclined to burn > , SPARKPLUG FOR STARTING MAIN NOZZLE STARTING NOZZLE K KEROSENE OR GASOLINE Se) generating plant. Note of combustion chamber where rg is applied above steam coils The improved Doble steam car, with hood cugtotted to .show position -At right: Control m hanism, showing wheel throttle ITH such authorities as th ies: scale tends to i on Ahe inside: of the. boiler ‘to compete with the gaso- pA 3) tubes, and pilot lights have- the habit of going out. All of these’ draw- backs haye made it im- possible for the steam car line car in spite of its un- disputed superiority in fuel economy. Doble has succeeded in eliminating a great many of these disadvantages. His greatest achievement, probably, lies in the perfec- tion of a quick-action starting mechanism. Instead of the usual pilot light for steam- ing up, he uses a Spark -plug actuated by a storage battery. Compressed air, stored in a tank, is released and allowed to shoot past a nozzle. This causes a suction that draws a rich mixture of fuel, either. kerosene. or gasoline, in the form of a spray, into the combustion chamber, where it is ignited-by the spark plug. The heat is very intense. In fact, Mr. Doble claims that a pressure of 750 pounds of steam can be obtained in 30 seconds. During the first five seconds the fuel is supplied by the starting nozzle. There- after the spark automatically stops, the compressed air stops flowing, and a blower motor provides the air that draws fuel from a main nozzle. After the steam pressure has reached 750 pounds and the temperature 800 degrees, the blower motor circuit is opened by the control system. Fire ceases, the starting air tank is recharged for the next start and the steam in the boiler is sufficient to keep the car running. When the pressure runs down, the fuel is supplied automatically to the combustion chamber and ignited, but stops when enough steam has been gener- ated. The steam generator is a single tube 476 feet long, made up of 12 spirally wound coils of steel tubing, starting with a diam- eter of one half inch where the feed water enters, and increasing to 13/16 inch where the superheated steam leaves the generator. A novel feature is that of the combustion N&\ WHEEL THR CONTRO : TO ENGINE | LIGHT AND IGNITION Ag CONTROL SWITCHES # ™ r y We ° 2 A a MS \.. ale VA Mane STEAM GAGE ie chamber, which is designed so that the fire does not strike. the coils. Power is provided by a four-cylinder double acting engine consisting of two 2%- inch ‘high- and two 4%-inch low-pressure cylinders. The exhaust steam is condensed in a specially designed radiator and re- turned to the water tank. No cooling fan is required. Fuel under pressure’is fed to a float chamber from a 25-gallon tank at the rear of ihe chassis. Rubber Silencer Prevents Rattling of Hood A NOVEL rubber silencer, said to elim- inate all rattles in auto hoods, consists of a vacuum cup that grips the surface of a hood firmly, at the same time gripping the hood fastener by means of two cleats. The device thus prevents movement of the hood. How the rubber silencer is adjusted

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Popular Science Monthly How I Made My Car Ferry Itself across Lake By G. F. Korte AN you im- agine a family marooned on a modern ranch? That is exactly the plight in which my family and I found ourselves at Barrett, San Diego County, Calif., only a few months ago, because three miles of deep water at the front and the lofty moun- tains at the rear formed impassable barriers. pe The city of San AND Diego had _ con- structed a dam across the Cottonwood Ak oe River about six miles NS below our ranch, and the resulting reser- voir lake swelled by heavy storms, cut off our only road to the outer world. Something had to be done. From stuff that was lying around the place I made a rude rowboat and oars, and rowed across the lake, where I was able to send out mail. But to get food and other supplies a long journey to the city was necessary. Even if I could reach the city on foot, neither I nor my rowboat would prove sufficient to carry back the things we needed. There seemed but one way out of the difficulty— to devise some way of get- ting my car across the lake. I decided that a flatboat offered the only solution. I had no help and no ma- terials. The floods, how- ever, had strewn the lake with driftwood, and this I gathered, using my rowboat Gear Teeth Are Tested by New Instrument OR accurately testing i i Fk of gear tooth profiles and the spacing of teeth in production work, an instru- ment has been invented which is easily operated and equally adaptable to spur and helical gears. It has a range of from three to 10 diametral pitch, may be used to check any pressure angle and can gear while it is in place in the machine. In making the test of a gear, the instru- ment is located over one tooth and rocked into contact with the adjacent tooth. One flank of the tooth rests against the surface hha of a fixed finger, marked “‘A”’ in the accom- panying illustration, and is by the pressure of a movable member, “C,” which is adjusted to the opposite flank of the same tooth. The contact with the adjacent tooth is made by a movable indicating surface mounted on two thin, flat. act as pivots without backlash. The con- tact surface can be adjusted so that gears of different pitch can be tested. The dial indicator, which records any pe ra BDLE. WHEEL TIMBER ”, gnAFT pT i aa 4 ee SMALL SP _. WHEEL BOLTED TO SPOKES. ; 3 ~ ar a G. F. Korte and his auto-driven flatboat built of driftwood How My Car Serves Me A Prize Contest Announcement FTER you have read of Mr. Korte’s,ingenious use of his automobile, write and tell us about the unusual uses to which you put your car. What useful work does it do in addition to its regular duties in transportation? What led you to put your car to this novel service? What have been the results? Let your answer be based, not on theory, but upon actual experience. You may have hit upon an idea from which we all can learn. For the best letter of not more than 400 words, accompanied by illustrative photographs or drawings, we offer these prizes: $20, first prize; $10, second prize; $5, third prize. Winning letters will appear in the January issue. Address Automobile Contest Editor, Popular Science Monthly, 225 West 39th St., New York City. Each letter will be considered by a board of editors whose deoision will be final. — Contributions to this contest cannot be returned un= less accompanied by a stamped, self-addressed envelope. Competition closes September 20.” deviations in the profile or the spacing, is actuated by a lever connected with the indicating surface and is calibrated so that each division of the scale represents a movefnent of .0002 inch of the indicating surface. Since the instrument tests the surfaces most essential for smooth and quiet operation, it is a simple matter to establish limits of tolerance for inspecting gears designed for any particular class of work. the uniformity be applied to a Operation of the new apparatus in testing profiles and spacing of gear teeth is shown at the right. Note how dial in- dicator is operated by lever con- nected with the indicating surface held in contact springs, which for the purpose. In a few weeksI was able to construct a scow, 12 by 15 feet, sufficient to support my Ford. At the be- ginning I had intend- ed to try to paddle or sail the scow across the lake, but as it neared completion the thought occurred to mé that it might be possible to supply motive power from the car’s engine. Accordingly, I rigged up a platform that permitted the rear wheels to revolve and geared one wheel to a shaft, which I made of a piece of four-by-four timber supported on wooden bearings. Then I built paddle wheels for the ends of the shaft, made a rudder of a 10-foot length of 12-inch plank and was ready to start. My queer craft has been an entire success. With it I can make the three-mile journey across the lake in less than an hour. The car’s motor has proved sufficient to drive the lighter across the lake, even when it is loaded with 1500 or 1600 pounds more than _ the weight of the car itself. I run at low gear, for a boat like mine is built more for cargo than for speed. Except for the sprocket wheel and chain used to turn the shaft, which I re- trieved from some old farm machinery, every part of the scow is ‘constructed en- tirely of driftwood. I’m rather proud of my sturdy craft. It’s seaworthy and reliable in calm or storm. >a Dm of = at a ae ae ee eh he a Fe ee a ee ee ie

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ke ee. In -I was truct a 5 feet, support the be- intend- ddle or across t as it tion the red to ght be supply > from 1e. gly, I latform od the revolve 2 wheel hich I iece of timber wooden hen [I for the nade a length id was s been ith it I ee-mile ake in 1€ car’s ficient across n it is r 1600 n the uf. = a boat ore for rocket sed to 1 I re- d farm ; of the d en- I’m sturdy y and orm. _ear while speeding at 50 miles ‘an hour, a five-passenger tour- - changes. : The engine went the Popular Science Monthly Autoand Plane Take on Gas at High Speed Non-Stop Refueling Proves Successful O's the non-immortal tire now stands in the way of non-stop, long- distance motor journeys such as wheels never before achieved. No longer need automobile engines, capable of better than mile-a-minute speed and astounding -endurance, halt unwinded in mid-course ‘for oil, fuel, and water. ineased rubber hose, through which the gasoline was transferred to the tanks of the lower plane. quired for the transfer of 50 gallons of gaso- line in this manner. The transfer was made during an attempt of Captain’ Smith and Lieutenant Richter to set an: endurance Only two minutes was re- - =e Fed with these necessities from a newly invented supply ing car.recently completed a record-breaking endurance run_ of 3155 miles in 50 hours and 21 minutes.on: the Indianapolis speedway. .The average speed was 62.63 miles an hour. Only Three Stops Made The speed of the record- - breaking auto was diminished only slightly as the supply car . nosed up alongside, swung out a mechanical arm holding a flexible hose, and through it. transferred fuel to.the tanks of the racing car. The entire 3000-mile run was made with mS 4+& 48 FOOT HOSE Refueling in midair at 90 miles an hour fuselage. In one test Lieute- nant Seifert was, compelled to land with the 48-foot ~ hose dangling under his machine. Finally, it was found that by enlarging the.hole in the bot- tom of the fueling plane, the hose. could be hauled aboard easily. : Since the wide roads of the air make high speeds safe, and Since tire changes never fret only three stops, all for tire distance without a break. A. H. Means, head of the Contest Bureau of the Ameri- ean Automobile Association, commenting on this remarkable achieve- ment, said: “The perfection of the supply car and its methods of transfer will greatly lengthen the distances between stops in long-distance engine tests on a speedway. Only the necessity for tire changing now stands between today’s testing records and relatively indefinite non-stop runs.” A parallel achievement in the air was accomplished above San Diego, Calif., recently, when four army aviators success- fully transferred gasoline from one plane to another while both machines were in full flight. Rushing through the air at a speed of 90 miles an hour, the supply plane, manned by Lieuts. Virgil Hines and Frank Seifert, was guided to a position directly above a second plane flown by Capt. Lowell Smith and The men in the upper plane ran down a 48-foot steel-wire- Lieut. John P. Richter. Lieuts. Frank Seifert (left) and Virgil Hines in the refueling plane from which they transferred 50 gallons of gasoline to the tanks of a plane flying below at 90 miles an hour. Note the 48-foot fuel hose, which was lowered as shown in the inset flight record by flying four days and four nights without stop. Preliminary refueling tests developed one fault. That was the inability of the fueling plane pilots to haul the hose back into the is . : S & £ s x a ' Pt : 4 Wwe" | in im. Transferring fuel, oil, | ; and water while trav- =i é eling at a speed of 50 miles an hour. Nos- ie, 2 || ing alongside the ren racer, the supply car extends a mechanical arm holding a flex- ible hose through which fuel is deliv- ered on the run the impatient.aviator, this sky feat means that’ only the limited endurance. of modern automotive power now pre- vents non-stop flights surpass- ing even the recent transcon- tinental flight of the two army aviators, Kelly and Macready. Planes now can be insured ‘against running out of fuel or oil over long stretches that offer no landing facilities. But tire changes still fetter the automo- bile. Perhaps a fifth wheel that will drop to the road and do duty for the one being changed, waits just around the corner of tomorrow’s ingenuity. Diameters of Far Distant Stars. Measured B* THE invention of an instrument known as the “interferometer,”’ Prof. Albert Michelson, of the University of Chicago, has made it possible for scientists to measure the diameters of far distant stars which, even to the most powerful telescopes, appear as mere pinpoints. of light. Two mirrors attached to a slide on this instrument, which is 20 feet long, reflect beams of light from the star back and forth until they are finally directed against the mirror of a giant telescope that magni- fies them many thousand of diameters. The light from the star, as reflected by the mirrors of the interferometer, is broken up into its spectrum, and the mirrors are moved about until the two spectra coincide. When this happens, triangulation is used to obtain the diameter of the star. The dis- tance between the two mirrors, known length of light waves, and the previously determined distance of the star from the earth supply the data for the astronomers’ calculations.

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Popular Science Monthly

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. 3 oe ‘ Sor pF ata Santee a Portable “Jack” Scale Hours of time may be saved the shipper by a new portable weighing machine, shown above weighing a locomo- tive, which makes it possible to weigh car- loads after they have been put in the car. The machine acts on the same principle Weis hs a Locomotive as the ordinary “jack.” It is put under the wheels of the car, one wheel at a time, and the grand total computed from the four weights as recorded on the scale dial. Wagons and trucks also may be weighed by this device.

New Open Fire Grate Burns Its Own Smoke O DO away with the disadvantages of open fireplaces, measured by house- wives in terms of sooty curtains and dark- ened wallpaper, an English inventor has perfected a coal fire grate which, he claims, consumes its own smoke. The grate is fed from the top. By means of a device that causes the smoke to be mixed with the gases fromthe Burning coal, the smoke is consumed before it has a chance to escape into the room. Experts estimate that only about 20 per eent of the heat from coal burned in an ordinary open grate is effective in warming aroom. With the new invention, the pro- portion of efficiency is said to be large.

ae my Feeding the grate from the top

Water Bicycling Is Latest Sport for Bathers ICYCLING in the water is the newest sport at the fashionable seashore re- sorts along the Atlantic Coast, where bathers ride an odd craft imported from England. . In the water, the craft is submerged, ex- cept for air tanks fore and aft. Pushing the pedals operates a three-bladed propeller that carries a guard to prevent it from being fouled by seaweed. Steering is accomplished vy handlebars, which in this case turn a rudder instead of a front wheel. The sport is safe, even if the craft hap- pens to be upset by waves, for the air tanks supply a never-failing life raft.

AN early issue, Dr. Minna C. Denton, assistant chief of the United States Office of Home Economics, will tell how to save from 25 to 50 per cent on your household gas bills.

Old Razor Blades Turned — into Handy Scraper NE of the (Af “3 most valu- é a able uses yet de- vised for old, dis- carded safety ra- zor blades is that of a scraper for removing paint or varnish in any job of refinishing. For this pur- pose the handy razor blade holder shown in the il- lustration has been invented, and now is being manufactured. The razor blade is inserted in a metal clamp and fastened securely by means of a thumbscrew. A comfortable grip for the fingers is provided, The keen cutting edge also may be used in scraping and smoothing woodwork.

Pocket Toilet Outfit Has Disappearing Brushes

[ pSSIGNED especially for use in travel- ing, a novel combination toilet outfit includes two disappearing clothes brushes, a mirror, comb, and manicure stick. It can be carried in a woman’s shopping bag.

Ingenious Creel Strap Is Quickly Adjusted Cc THE knapsack principle, an Idaho inventor has designed the fisherman’s creel strap shown below. When not needed, the fishing basket may be slung on the back. A simple adjustment of the strap permits the basket to be lowered instantly.

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Vu tua lida” lila AY. <a power

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Popular Science Monthly oe a Rigi aie die Sea 1 now is blade is fastened rew. A rovided, be used ork. Mddhddddddddededddeedeeddeddeedded ddd dtdceaceede “a "Wy ds Lddddddddadddddeddsiddddiddddddddde Has Nc 1eS Heavy traffic along Fifth Avenue, New York City, where scientific analysis of the air revealed the presence of poisonous carbon monoxide in dangerous proportions. Drawings at the left show how the proposed “smokestack” vertical exhaust from a car standing still or in motion, would keep the dangerous exhaust gas above the heads of pedestrians and motorists a = x ousis . ~ = DLV DWWWwWWWHUwV,° Whnpn ai] w Wow Ho NDT OW rH.’ "Qo n travel- let outfit brushes, It can bag. p Is in Idaho nerman’s t needed, the back. . permits y. Exhaust Auto Gas,a Lurking Assassin How Scientists Fight Odorless, Tasteless and Colorless Carbon Monoxide, a Growing National Peril By Raymond J. Brown were to breathe air containing two parts of carbon monoxide to 10,000 parts of air continuously night and day, a large proportion of the population would be incapacitated for work. Many with weak hearts would die.” To every city dweller and city worker, this recent statement of Professor Yandell Henderson, of Yale University, in a report to the New York Academy of Medicine, comes as a danger signal, warning of an in- creasing traffic menace to human health and even to life itself. For it merely sup- plements a more startling assertion by Prof. Henderson, which is this: On every street in America where motor traffic is heavy, carbon monoxide is present in more deadly proportions even than those listed as dangerous to life and health! From the exhaust of every gasoline driven automobile, motor truck and _ taxicab, clouds of this poisonous gas are poured every minute into the atmosphere above city pavements. It is a gas more dangerous, according to Professor Henderson, than the smoke rising from the chimneys of dwellings and factories or from the funnels of loco- motives. It is the very same gas that fre- quently causes the death of miners; the same gas which has killed many persons who have allowed their automobile engines to run in closed garages. Professor Henderson bases his amazing ae THE entire population of a city statements on the result of scientific tests which he recently conducted on Fifth Avenue, New York City, in collaboration with Dr. Howard W. Haggard, of the Yale University laboratory ot applied physiol- ogy. And, since every city has its Fifth Avenue—a thoroughfare through which an enormous amount of motor traffic pours each day—his findings apply to great cen- One type of auto exhaust “chimney” proposed by Professor Henderson, to carry. gase} upward without spoiling the car’s appearance or performance ters of population throughout the country. That thi dangerous situation has not already produced serious results, Professor Henderson attributes to the fact that the millions who breathe the poisoned air of city streets usually do so only for a few hours each day. The practically pure air which they breathe at night acts as an anti- dote for the poison gas. Even now, Pro- fessor Henderson asserts, thousands of peo- ple whose business takes them to streets where motor traffic is heavy are unknow- ingly suffering every day from carbon monoxide poisoning in a slight degree. The immediate effects are headaches, lassitude, and, in some cases, extreme dizziness and violent nausea. . The lasting effects are ex- treme nervousness, irritability, and lack of energy. Anemia and a proneness to tuber- cular infection may follow long-continued subjection to the gas. The menace of carbon monoxide is all the more deadly because of the insidious method of its attack. It is colorless, odor- less, tasteless, invisible. In consequence it may be breathed in quantities sufficient to cause-permanent injury, or even death, before the. victim is aware of its presence in the atmosphere. A few inhalations; _then come sudden dizziness, acute nausea, muscular weakness. The victim falls, and, unless he is removed instantly from the poison-laden atmosphere, he is likely to die. Only a few seconds intervene between the first realization of danger and death, a fact which is proved by the number of persons who, realizing their peri], have been unable

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34 to struggle a few feet across their garage floors and throw open the doors. The attention of the nation was first called to this danger in December, 1917, when Nat Wills, the famous comedian, died in this way. He had started the engine of his automobile in the garage ac the rear of his home in Woodcliff, N. J., to ‘“‘warm it up” preparatory’ to taking a drive and was overcome by carbon monoxide. He died while trying to reach the door. Death, of course, comes only in extreme cases, when the amount of carbon monoxide inhaled is large. When the gas is present in the air in smaller quantities—say about three parts of carbon monoxide to 10,000 of air—the effect on those who breathe it may be compared to that which would be produced on anyone suddenly trans- ported from sea level to one of the highest peaks of the Andes—dizzi- ness, nausea, lassitude and head- aches lasting 20 hours or more. Drivers Are Affected Breathing the gas in a large quan- tity for a short period will produce an effect similar to that of alcoholic intoxication. In this connection, Professor Henderson declares that drivers on city streets are likely to be rendered incapable of properly operat- ing their vehicles by carbon monoxide poisoning at almost any time. Carbon monoxide attacks the hemo- globin, the red coloring matter and oxygen- carrying element of the blood, and prevents it from carrying oxygen from the lungs to the body tissues. The carbon monoxide re- places, part for part, the oxygen which the hemoglobin is carrying—a fact that ex- plains how the danger from inhaling it in- creases in proportion to the amount taken into the lungs. Traffic police on duty on streets where motor traffic is especially heavy frequently have complained of dizziness, headaches and lassitude at the end of their day’s work. They have believed this to be due to greater physical and mental strain when directing huge streams of traffic than when performing other duties. Motor bus and taxicab drivers in crowded streets also have believed that the worn out feeling which oppresses them at the end of the day is due to the strain of constantly stopping, starting, and turning aside to avoid col- lision with other cars in heavy traffic. Yet science now tells us that they are suffering from carbon monoxide poisoning. Garagemen Suffer Depression Employees of public garages and repair stations where automobile engines often are permitted to run for long periods suffer similar depression. Professor Henderson and his associates were informed by the managers of several repair stations that their men frequently have to quit work and rest because of in- explainable headaches and weakness, which the investigators assert undoubt- edly are due to carbon monoxide poison- img. In one large shop where Professor Henderson inquired how many of the men went home each day with headaches, the answer was, “Nearly all of them nearly every day.” Science already has begun the search for a means of eliminating this newly found sneakthief of the nation’s health. Pro- fessor Henderson himself has suggested as a remedy, that all automobiles should be compelled to carry chimneys, opening above the highest point of their bodies. This Popular Science Monthly would throw the deadly poison of their ex- hausts into the air, far above the nostrils of pedestrians and motorists. The prevailing ear construction which places the exhaust below the body, he says, is unscientific and unsuited to present conditions. No danger will come to persons in the upper stories of buildings by this revolutionary method of exhaust, he adds, since science has dem- onstrated that the air within a building tends to circulate upward through the In this car, equipped with apparatus for obtaining in- stantaneous air samples, Prof. Yandell Henderson made the tests which revealed the peril of carbon monoxide building, rather than in from the windows. Other scientists who have been stirred by Professor Henderson’s revelations have suggested great ventilating fans to carry polluted air of the streets far above the roofs of even the tallest skyscrapers. Ven- tilating engineers and sanitary authorities generally are turning their ingenuity to a solution of the problem. The investigations undertaken by Pro- fessor Henderson and Dr. Haggard were the first of their kind. To determine scientifi- cally the exact amount of carbon monoxide diffused through a street where motor cars pass, a small car was equipped with sam- pling cans, bags and bottles. The cans, filled with water, were connected by a pipe Taking the blood from a miner for a test to determine the presence of carbon monoxide poison. The gas replaces the oxygen sup- ply carried by the hemoglobin of the blood with a funnel on the windshield, and, as the water flowed out of the cans, air was drawn in. These samples of air were preserved and analyzed in the laboratory, samples being taken in traffic of varying density. The investigators knew at the outset that the amount of smoke issuing from a motor exhaust has no connection with the amount of carbon monoxide given off, for it had been determined by the United States Bureau of Mines that smoke 2nd smell are due to excess oil, while the carbon monoxide Pamiiar Seience Manthiv is developed only by the combustion of the gasoline. 5 ae Observations were made of cars standing still with their motors idling, and ‘ears jn motion. In the case of a car standing still, it was shown that the vapors from the ex. haust spread in a cone, so that a man stand- ing a few feet back of the car is surrounded by an atmosphere containing four to six parts of carbon monoxide to 10,000 parts of air—a dangerous proportion—while the occupants of another automobile 30 feet in the rear would be breathing two parts of carbon monoxide to 10,000 parts of air. When a car is in motion ‘the cone of diffusion is elongated. In damp, still weather the proportion of carbon monoxide to air is considerably increased. ° Benzol Increases Gas The investigations also developed the fact that fluids frequently mixed with gasoline to increase its power or combustibility — particularly benzol—cause an increase in the amount of carbon monoxide in the city streets. In his report to the Academy of Medicine, after noting the fact that a dangerous percentage of carbon monoxide in the air is no unusual condition in a thoroughfare having heavy motor traffic, Professor Henderson said: “It is a surprising fact that in spite of modern scientific knowledge and the exten- sive legal protection now afforded public health, automobiles are almost always built so as to discharge their exhaust gas near the ground, instead of vertically upward as all other smoke and noxious vapors are deliv- ered. If the exhaust gas of- automobiles constantly contained soot particles, or what we term smoke, there never would have been any question that the automobile én- gine should be provided with a chimney. “Fortunately, we have been able to ob- serve the working of the vertical exhaust, for in some cities it is already customary for bakery wagons to be fitted with such a pipe to protect their cargoes. No appre- ciable loss of power results. The gas thus delivered, being warm, continues to rise. While it is rising, cool fresh air blows down along the walls of the buildings, tending to prevent the gas from entering windows.” Valuable Experiments in Mines’ In mines, too, extensive research work in the campaign against carbon monoxide gas has been carried on. Dr. R. R. Sayers, chief surgeon of the United States Bureau of Mines, and W. P. Yant, a chemist of the Pittsburg experiment station of the bureau, have devised a new method to determine the presence and extent of carbon monox- ide poisoning. They have invented an ap. paratus for testing blood of victims and by their method the presence of the poison is established in three minutes and its extent within 15 instead of 24 to 48 hours as formerly. Dr. Hubert Work, Secretary of the In- terior, and a former president of the Ameri- can Medical Association, has predicted that the apparatus soon will be in universal use by physicians. He bases his prediction on the growing menace of carbon monoxide in the streets as well as its presence in mines and industrial plants. But this is just the starting point in the scientific war against this new danger to national health—a danger that demands immediate solution by the nation’s scientists and by officials of our cities.

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extent urs as Pepular Science Monthly Pontoons Raise Wreck from Sea art ni a COMPRESSED AiR PONTOONS ELECTRIC POWER CABLE TO TRACTOR \ SUBMARINE TRACTOR TO GREAT DEPTHS, & SIDES OF SHIP ANI ATTACHED TO PON N improved method of salvaging sunken ships was demon- strated successfully off Whitestone, Long Island, recently when the wrecked coastguard cutter Scally was raised by com- pressed air pontoons. This new system consists of two working units—a submarine tractor driven by electric motor, and open-bottom, submersible pontoons. The tractor is lowered from a lighter to the ocean bottom, where it travels on endless treads like a huge crab. The body of the tractor is a “diving”? chamber (at the right), large enough to hold two men. In it are fixed two steel drills which bore five inch holes into the sides of the sunken vessel. The pontoons then are drawn down and attached to the wreck by hooks inserted in the bored holes. Their buoyancy is sufficient to enable an electric motor to raise the wreck 1 AR a et iy en mee qn see yee - {7 >

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na cc RE OR hOB AHO Sait in Ss lca Nandi tte Popular Science Monthly The Science of Fire Fighting Prevention of Disaster Is First Aim of Modern “Smoke Eaters” Who Battle with Flames and Risk Lives in Thrilling Rescues As Told by Chief John Kenlon of the NewYork City Fire Department ODERN fire fighting is a scientific M profession. It may be compared with the profession of medicine. All fires have common characteristics that enable a fire department officer to use certain clearly defined principles in coping with them, just as a doctor, through his and other causes of a more or less acci- dental nature. It was a careless smoker who caused the terrible Asch Building fire in New York City in March, 1911, in which 145 girl employees of the Triangle Shirt Waist Company were burned’ to death. Careless- ness also may be blamed for the loss of more than 600 lives in the Iroquois Theater fire in Chicago, the most frightful theater fire the country ever has known. In preventing catastrophes such as these, probably the most effective weapon de- vised by science is the sprinkler system, knowledge of disease symptoms and effects, is able to effect cures for individual patients. To-day the analogy between the profession of fire fighting and the profession of medicine never was more apparent. Modern medical men seek to control dis- ease by striking at its root, elimi- nating its causes, rather than by curing their patients after they have become sick. Just so the modern fire fighter endeavors to prevent fires before they have broken out, rather than to attack them after they have started. A Frightful Danger Yet in this effort he is hampered by an amazing public apathy to the ever-present and frightful danger of fire. About 15,000 per- sons die from fire in this country every year. Last year, according to recently announced statistics of the National Board of Fire Underwriters, the total fire loss— fire waste, I might say—in the United States was $521,860,000. No other nation in the world ap- proached this figure. The per capita fire loss in the United States was the greatest in the world—$4.75, as compared with 72 cents in Great Britain. Now, there is no doubt that America leads the world in the development of scientific fire fight- ing apparatus. The American municipal fire departments are as well-drilled and as efficient as those of any other nation. Why, then, the appalling difference between our fire loss and the loss suffered by other nations? Carelessness Chief Cause Of several contributing causes, the principal one is carelessness. This statement, I believe, is amply borne out by the fact that 65 per cent of the fires in the United States occur in dwelling houses. People are habitually more careless at home than in their shops and offices, although carelessness also plays its part in causing fires in other places be- sides the home. In industrial plants and office buildings care- lessness---usually with matches and lighted cigars and cigarettes —almost. invariably takes pre- cedence over defective electric wiring, explosions, back-fires from internal combustion engines The New and the Old Way in Fire Fighting A= BOVE is a remarkable pho- tograph of a recent thrilling rescue from a burning East Side tenement. The inset shows Fireman John A. Johnson carry- ing a tenant through smoke and flames down the aerial ladder with which the modern hook and ladder truck is equipped. At the right is one of the anti- quated fire carts which attempted to fight the flames that destroyed the City of Smyrna a year ago which sprays water from.a central water plant automatically as soon as the heat in a building rises to a certain point—usually about 155 degrees. Automatic Protection Installation of scientific sprink- ler equipment assures almost ab- solute protection against fire for industrial plants, hotels, office buildings, public meeting places, warehouses and similar struc- tures. Its efficiency has been demonstrated time and_ time again. It holds a fire in check until the fire department arrives and it also automatically sounds the fire alarm. Two garages caught fire in the same New England city one night about a year ago. The buildings were of the same size and each contained about 50 automobiles. The fires had similar causes and about the same opportunity. of spreading. And yet one of the fires did only slight damage, while the other destroyed the garage and all its contents. Checked at the Start A sprinkler in the first building checked the fire until the fire de- partment arrived to quench it entirely. In the second building the absence of a sprinkler system permitted the fire to gain so much headway that it was impossible to prevent the destruction of the building and the automobiles within it. Yet with incidents of this sort occurring almost every day, own- ers of buildings which should be protected by sprinklers are slow to install them. Strange as it may seem, I believe that many owners of large buildings never have heard

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a — mae” r "3 Fighting a stubborn blaze in downtown New York. Note the water tower apparatus that raises hose line 10 stories above the street. At the right, a fireman protected by gas mask is shown rescuing a com- rade overcome by gas while fighting of sprinkler systems. Others, who know about them, have failed to install them, preferring to take a chance on a fire break- ing out. Automatic fire doors, which, operated by, thermostats, close when the “heat rises, thereby shutting off the draft which would cause the fire to spread, are another form of fire protection which science has furnished, as are chemical fire extinguishers. Few dwelling houses contain fire extin- guishers. Every home should have at least one, and every member of the family should be instructed in its use. In the ideal dwelling house the first floor at least should be fire-proof, but since we have not yet reached the millennium, that, of course, is not now the rule. People can, however, endeavor to make their dwellings as nearly fire-proof as possible. They can prevent inflammable Popular Science Monthly a suffocating sub-cellar fire which permitted fire de- partments to use general principles in combatting them. Briefly, these broad principles are: The outbreak must be confined to as narrow a space as possible. Contiguous _ property must be protected by every means available. Injury and loss of life must be prevented. Efforts must be made to centralize the outbreak as a whole. All forces must be concentrated on the point of greatest danger. As in the movements of troops in war, firemen endeavor to outfiank the fire. Cer- tainty and rapidity in their movements are necessary to success, for fire is a dangerous enemy which takes no prisoners and uses rubbish from accumu- lating. If they use gas light, they can see that the flames are sur- rounded by proper guards. They can see to it that every match they use is entirely ex- tinguished before they throw it away. They can prevent window draperies from being blown against gas jets. They can keep matches out of the hands of chil- dren and they can store matches where rats cannot gnaw them. I said at the outset that all fires possessed points of similarity anit { ak \ ‘ : Jaa Hin) LS aL 1} av w omns -— Ss PNG Ee ara Ne every mistake of its foe to its own advan- tage. Fire also may be said to keep abreast of the times. The very development of the automobile and the gasoline engine, which has given us motor-driven fire-fighting apparatus, at the same time has supplied fire with new ways of spreading havoc. At the very time when new rules and devices made theaters more safe from fire hazards, came the highly inflammable celluloid mov- ing picture film, a new ally of fire in its fierce warfare against man and his property. As an indication of just how dangerous a men- ace celluloid film is, France has just passed a law making the pos- session or use of any but non-inflammable film a penal offence after March, 1925. Chemicals, whether in great chemical man- ufacturing plants, in corner drug stores, or in storage, are a fre- quent cause of acci- dental fires, difficult and dangerous to control. The heart of the scientific fire system at the national capital. Here each alarm is recorded. Six.ultaneously it is sounded in every firehouse in the District of Columbia. Note the elaborate automatic signalling and recording mechanism Not long ago a large warehouse in Jane (Turn to page 96) cory, ge tojcinenrn nr ee he, AMES Aah A 5 Oa TN ~~ tn nn ts i Nise

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ila aici. = > ai . —- Te Ah a aa il ttl REMARKABLE feat in precise ma- chine work on an enormous scale was accomplished in the shops of the General Electric Company at Schenectady, N. Y., when the 40-ton steel shaft shown here was tooled down on a giant lathe to the exact Popular Science Monthly “Forty-Ton Shaft Tooled to a Hair’s Breadth size necessary. It will be the main shaft of two motors, each capable of developing 3250 horsepower. An error in cutting of more than one one-thousandth of an inch would have rendered the shaft useless, but the work was completed successfully. High Speed Telegraph Code Invented by General ‘sat the Morse telegraph code, in- vented 80 years ago and used with scarcely any modification ever since, is fundamentally unscientific and unsuited to the new developments in telegraphy, par- ticularly in radio, is the belief of General George O. Squier, chief signal officer of the United States Army. As a result, he has devised a new code, which has demonstrated its effectiveness. General Squier has endeavored to adapt to telegraphy the modulation of telephony and music. Using the familiar dots and dashes of the Morse code as a basis, he has invented a system of transmission in which, by making all signals of the same length, he obtains an increase in sending speed 165 per cent greater than that of the Morse code and an accuracy in reception never before attained. The system minimizes the likelihood of interference in radio messages and lessens violent disturbances in the ether which hamper radio transmission. Instead of producing signals by alter- nately turning on and shutting off a flow of electric current, General Squier causes an alternating current to flow from his trans- mitter uninterrupted, distinguishing his sig- Transmitting the new code automatically nals by varying the intensity of the in- dividual elements—the dot, the dash and the space. It is like signalling with a single continued musical tone. A faint sound would represent a dot, a louder sound a dash, and a still louder one a space, each signal occupying the same length of time. The Squier code may be sent automatic- ally by a transmitter of the type shown. Safety Curb Divides Road at Dangerous Curve N INNOVA- TION in high- way safeguards is a center curb at a dan- gerous turn in a road under a Southern-Pa- cific railway bridge at Weimar, Texas. The middle curb, eight inches high, divides the roadway into two lanes, each 10 feet wide. An eight inch concrete post at each end warns thr motorists to “Keep © Courtesy Enginecring World to the Right.” ~ attached to the door, a lever and a rubber Non-Drip Coffee Strainer Protects Table Linen F{ OUSEWIVES who are continually scrubbing out stains caused by tea o Ne coffee while it is being strained will welcome punct the new non-drip cold | strainer recently pouns invented. loose! This new sheet strainer is reinf¢ equipped with a appli small basin slung Bl underneath. ings : When strainer is repal in use, the basin case is pushed aside. teria Afterward it hole moves back into place position beneath first the seive, where cemé it catches the inch drops that other- quirs wise would land tire on the table- cloth and stain it. Novel Door Guard Protects Housewife from Intruders | PROTECTION for the housewife who is timid about answering door calls is furnished by the door guard that grips the floor, as shown below. It may be pushed into place or released by a movement of the foot. When in place, an intruder cannot possibly open the door beyond the point at which the guard holds it, unless he smashes - the panels. ; The device consists of a bracket which is shoe that grips the floor. The latter is described by its inventor as ‘‘100 per cent non-skid.”” Unlike chain bolts, this device permits the door to be opened as far as the person within the house desires. The lock can be attached easily and is manufactured in various sizes so that it can be used on practically any door. i This secure door guard can be snapped into position by the foot

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ainer en ontinually by tea o 1 welcome »tects iders wife who r calls is rips the pushed it of the ’ cannot point at smashes » which is 1 rubber latter is per cent s device ir as the y and is that it r.

New Cold Patch Repairs Cuts and Blowouts NY motorist can be his own tire re- pairman, and can successfully mend punctures and blowouts by using a new cold patching material, which is so com- pounded that heat will not cause it to loosen or weaken. The material comes in a sheet and is made of specially treated rubber reinforced by a special fabric. A patch is applied with a cold cement in the usual way. Blowouts, cuts and sand blisters in cas- ings are repaired according to approved tire repair methods, but no heat is used. In the case of a blowout, a piece of repair ma- terial is cut so that its edges overlap the hole by one half inch and is cemented in place. Another piece is cut to overlap the first piece one half inch all around, and is cemented on. One piece is added for each inch in tire section. A three-inch tire re- quires a three-layer patch and a five-inch tire a five-layer patch.

Exterior and interior views of cold patch applied to a tire hole Giant Merry-Go-Round Wind. Motor to Harness Breezes ARNESSING the wind for mechanical and electrical power by means of a windmill a,mile in circumference is the amazing project being worked out by a company organized by a Florida inventor. Experiments conducted with model 75- foot windmotors are said to have demon- strated the enterprise to be entirely feas- ible. The proposed giant windmotor will run on a circular, double-rail track to be laid on the ground. It will have 36 sails, each 12 by 25 feet square and mounted on a separ- ate truck. An elaborate gearing system on each unit will automatically adjust the Popular Science Monthly

Sneed en Picker Does : Work Ps, 10 Men MOTORIZED prune picker with which one man can do the work of seven to 10 has made its appearance in the Santa Clara Valley, California, where 65,000 acres of prunes are harvested each year. A metal roller, operated by a one-horse- power gasoline motor, carries the machine from place to place. The engine likewise operates a drum covered with steel pins that pick up the prunes from the ground as the drum rotates and deposits them on an elevator. There they are carried to a box above. Control of the roller and drum is from a handle resembling that of the ordinary lawnmower. The operator steers the de- vice to any desired soot. One man, working by hand, can gather about a ton of prunes a day, while the ma- chine can pick between seven and ten tons in the same time. Chlorine Gas Prevents ‘‘Flu’’ escent gas, used as a war weapon, now is being turned against the germs of influenza and is proving effective in pre- venting the disease. In experiments with students at the University of Arkansas, conducted by Professor Harrison Hale, dur- ing a recent “‘flu’’ epidemic, the gas treat- ment reduced the sick rate 90 per cent. The gas was breathed in very dilute quantity, preventing poisonous effects.

angle of the sails to take full advantage of the direction of the wind and also lessen the sail re- sistance when trav- eling against the wind. The wind motor will be connected with an electric dy- namo and the cur- rent generated will be held for use in storage batteries.

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The proposed ~winill motor, showing how

sails canoe around track. Inset shows 75-foot wind engine now in operation i

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ERTL AT Ree APE OR RiGee h on ke lS i min Ear aU Mee Ra Sa MARA D¢ teat HOR MIO NIOE A EE. lines this ethos The wrong way to fill an icebox Popular Science Monthly Comvtess New ¥ ork Tribune Institute The right way—lower temperatures Filling an Ice Box Scientifically T= two photographs above demon- strate, according to the New York Tribune Institute, the right and wrong ways of filling an ice-box. The icebox in the illustration at the left is “‘stuffed;’”’ that is, the food is packed in a haphazard manner which crams the com- partments, stops the circulation of air and prevents the refrigerating chamber from extracting the heat from the other sections of the box. The same icebox is shown packed scien- tifically in the illustration at the right. The food is arranged in the compartments in an orderly and systematic manner, permitting circulation; and with . .e different foods in the proper compartments. Note the cor- responding decreases in temperature in the compartments, indicated in degrees. _ This icebox is supplied with mechanical refrigeration, but the same principles re- garding the storage of various kinds of food are said to apply to any ice box. The com- parative figures on the insides of the doors show in degrees F. which parts of your icebox are coldest, and will furnish a guide for you in storing food, since you know from its character whether it requires very low or higher temperatures for preservation. Fortunes in Alaska Foxes prox raising on a large scale has been developed in Southeastern Alaska during the last year, according to reports of the Interior Department. Many farmers have taken up the raising of blue and silver foxes. Small islands along the coast, use- less for other purposes, have been turned into fox farms. Light Bulb Shield Cuts out Wall Shadows T HE glass shield on the upper part of the electric light bulb shown here pre- vents the light from causing the chains which support the fix- ture to cast shad- ows on the ceil- ing. A _ special kind of glass de- veloped by a Pittsburgh man- ufacturer is used in the shield to fil- ter out objection- able shadows. The shielded bulb Shield Protects Door Lock from House Breakers Ts novel shield prevents a house- breaker from opening a lock by shat- tering the glass and thrusting his hand through the opening. The lock is covered completely. Its bolt engages the shield as well as the socket in the door frame, making it impossible to unlock without a key. Closed Auto Body Made of Chicken Wi Wire and Fabric MANY a motorist prefers a car with a closed body, yet does without it be- cause of the additional expense involved, or because he fears that neither his skill nor equipment is sufficient to construct the metal panels himself. But now K. L. Childs, of Detroit, Mich., has designed a type of body construction for enclosed cars that offers many attrac- tions to the ambitious and skilful amateur. His idea is being developed commercially, but it may be used effectively also by amateurs desirous of remodeling their cars. Originality of Color and Design Fabric laid over ordinary chicken wire furnishes the groundwork of the body. It is lighter than a metal body; it minimizes the painting problem, because the fabric is already colored and enameled before use; it is more easily repaired and is not so easily damaged. Dents may be removed quickly, and the body is not subject to the noises and rattle common to most metal bodies. As in metal bodies, a frame or skeleton is built of wood. Over this the wire is laid and padded with cotton wadding, which is held in place by tacking a layer of buckram to the frame. The body is then finished by stretching over this relatively smooth but soft surface a special fabric, such as imita- tion landau leather, although any enameled or painted fabric may be used. The result is said to be a closed car as attractive in appearance as the most ex- “— t a oh : + | pensive, with the added ad- vantages that its color and design may be altered easily and cheaply, and that re- pairs can be made with little trouble. With the growing popular- ity of the closed car, the need for just such a body that can be built economically yet will prove durable for everyday use has long been apparent. j ) ae ee AS wawtheler At the left, the wooden § skeleton of the closed car body, showing how chicken wire reinforcement is placed over the wooden frame Below, the body nearing comple- tion. The wire is padded with cot- ton wadding held in place by buck- ram. Over this, a special fabric is stretched tightly Z. Ss Now to whi ing fot leap a separa ing of It is the su the mi An ec sun’s | liarly outer coroné atmos R Wil chemi some Will | quest solid ¢ of its energ In nomi: furni: gestic

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ut Will the Sun By Robert E. Martin EXT to creation itself, the sun N always has remained for mankind the supreme mysterv of the universe. Now we are on the threshold of an event to which astronomers everywhere are look- ing forward eagerly as an opportunity to leap across the barrier of distance which separates them from complete understand- ing of this source of heat and light. It is the eclipse of September 10, when the sun will be obscured by the shadow of the moon falling between it and the earth. An eclipse, which shrouds the glare of the sun’s center, gives the astronomer a pecu- liarly fruitful opportunity of studying the outer layers of the sun, particularly the corona, the uppermost stratum of its atmosphere. Reports Sun Is Cooling Off Will the coming eclipse reveal some new chemical element in the sun’s composition, some substance not yet found upon earth? Will astronomers find the answer to the question whether the interior of the sun is solid or gaseous? Will they learn the source of its tremendous, seemingly inexhaustible energy? In the opinion of some scientists, astro- nomical observation of that day even may furnish support to the recent startling sug- gestion that the sun is failing us! Not long ago Dr. C. G. Abbot of the Smithsonian Institution announced that the heat of the sun had fallen off 3 to 4 per cent in the last year or so. His an- nouncement was the result of observations made at the Smithsonian Institution’s stations in Arizona and Chile, where accu- rate measurement and tabulation of the intensity of solar energy has been carried on for 20 years. The discovery opened a field of interest- ing speculation. If the sun’s heat is to de- crease at the rate of 3 or 4 per cent a year, what will be the result in, say, 50 years? We have just passed through an exception- ally cold spring. Was that the first warn- ing given us that the sun, after millions and millions of years, is at last going on strike? Although we have still much to learn about the sun, we know that without the sun we could not live and our earth could not flourish. Withdrawal of sunlight and heat, even for a limited period, would plunge us into darkness blacker than the REVERS! NG LAYER PHOTOSPHERE SS SW ¥ 6° ivi Why ve) .”v el’, J, Wy, Fr>Fpn A bbwWW]] ””T"rbnwvraaek WWWAMD AN Popular Science Monthly Ever This diagram shows the chief layers of the sun—the photosphere, a brilliantly luminous envelope of vaporous matter; a reversing layer of cooler gases; the chromosphere, a sea of fire, and the corona dddaadidddudddudddiliddddddddjyyyypudddlllillhsaddddsy, MMA i uw SMNYOMBE. OMB AdWI9. WG This huge telescope in the new observatory at Pots- dam University, Ger- many, is expected to give astronomers new knowl- edge of the sun during the eclipse of September 10 blackest night, and into a cold infinitely more bitter than that at the poles. There could be no crops. The water which makes up two-thirds of our globe would be turned to ice. The artificial means of produc- ing light and heat which science has supplied us would be useless. We would be helpless to exist on earth! ,. en eee Soe Wag ir’ & Pe Fail Us: A WEEE cc ccc ldhededecccccedddddedeccccceedddlddddelbeeedccddadeaeussdeuataddae Courtesy G. P. Putnam’s Sons Enormous tongues of scarlet, flaming hydrogen shoot outward from the sur- face of the sun, sometimes rising to a height of 500,000 miles into space Science tells us that the sun is a huge ball of fire—and yet not fire as we under- stand it on earth—one hundred times larger than the globe we live on, and 93,000,000 miles away from it. It is a boiling ocean of white hot vapors, the surface temperature of which has been estimated to range from 9,000 to 13,000 degrees F., and from which at times have been flung flaming columns of gases, traveling 60,000 miles an hour and shoot- ing a half-million miles into space. Astronomy has divided the sun into definite concentric layers, which envelop the nucleus or central body somewhat as the atmosphere envelops the earth. Of the innermost region virtually nothing is known. Of the next exterior region, which the astronomer calls the “photo- sphere” and which we see as we look at the sun, considerable has been learned. Indeed it is through study of the photo- sphere that most of our knowledge of the sun has been derived. Upon the photo- sphere lies a third outer layer—the “‘chromo- sphere,” a red sea of fire 5,000 to 10,000 miles in thickness; and beyond that, gradu- ally fading away into the sky, is the corona. Whether the center of the sun is solid or gaseous is not definitely known, but from study of the photosphere by means of the spectroscope, astronomers have reached the opinion that it is gaseous. This study (Turn to page 97) 4

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Popular Science Monthly inverted Comet Adds Fuel to Sun UNLIKE EVERY OTHER COMET ole) ,| me?) | 2 Sone Le SUNWARDS The path of Baade’s comet, with its tail toward the sun, is shown above in relation to the earth’s orbit. Particles pulled from the comet’s head supplied 10 years’ fuel for the solar furnace ( By Scriven Bolton, F. R. A.S. r | “AHE only comet ever known to turn its tail toward the sun—one that supplied 10 years’ fuel to the great furnace of the sun—is Baade’s comet, recently discovered by Wal- ter Baade at the Bergedorf Univer- 47 : sity Observatory, Germany. 4 ALL COMETS EXCEPT BAADES Baade’s comet undoubtedly isthe § INVARIABLY TURN THEIR heaviest comet in proportion toits j TAILS AWAY FROM size ever discovered. The constitu- ent parts of which it is composed are much heavier than those of other comets. It is because of this fact that it has broken completely the hard and fast rule relating to the behavior of comets’ tails. In every other comet that has been observed the tail always has pointed away from the sun. This is because the tail is formed by the pressure of sunlight. Comets are clouds of gas, perhaps with some solid fragments, that come into our solar system from the outer space. Most of them go out and never are seen again, but a few, such as Baade’s comet and the famous Hal- ley’s comet, have regular orbits around the sun and come back again and again. Sunlight falling upon a small solid body or sphere, has power to exert a pressure or push upon it, in a direc- tion away from the sun. This is be- cause light itself is believed to be composed of tiny corpuscles of mat- ter, reckoned by billions for every square inch, and traveling out from 7 the sun at the rate of 186,000 miles §§ @2@- 7 ayn nnn nan every second. Th sph 4 e, the more it ™ aw nord aw The famous Halley’s comet follows the usual comet the push of light, and less by solar behavior —the tail invariably points away from the eravitation. sun. The record of the appearances of Halley’s ‘ comet every 76.8 years dates back to 240 B.C. Its In the usual comet, the very tiny visits alarmed Europe during the middle ages THE SUN HALLEY S COMET THE EARTH TURNED UPSIDE BAAD 4s | COMET Vie WED PA TAC LOSEAQUARTERS) LLL Here is a close-up view of Baade’s comet with its tail blown toward the sun. It was literally turned upside down and photographs showed it disintegrating rapidly particles of matter that make up the tail are smaller than the cor- puscles of light. The push of light on these particles is more powerful than solar gravitation. Thus they are pushed back out of the head of the comet and away from the sun instead of toward it. But if the size of the particles ex- ceeds that of the light corpuscles, solar attraction outweighs the push _ of sunlight, and the particles of the comet’s tail are attracted toward the sun, instead of away from it. This happened in Baade’s comet. During the comet’s last return, the amount of matter that was at- _tracted to, and fell into the sun, was sufficient to maintain the sup- ply of solar heat for about 10 years. Incidentally, a body the size of the earth, if plunged into the sun, would keep the solar furnace going for 95 years. in life

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3 eX- cles, push f the vard n it. urn, 3 at- sun, sup- pars. ' the sun, oing Popular Science Monthly Wild Birds Studied by Tags p ieapping and Banding Annual Backyard Visitors Is New and A healthy family of American waxwings, so called because some of their feathers are tipped with horny appendages resem- bling sealing wax. New facts about the habits of these and other migratory birds are being revealed by bird banding EGRESS fy HS Sig By Manus McFadden OW would you like to contribute H something to science and at the same time increase your own joy in life? Here’s your opportunity. Take up bird- banding, the science that is a sport. It is a fascinating science of discovery—the dis- covery, by means of identification tags, of the travels, habits, and individual charac- teristics of migrating birds that you see every day about your home. You don’t have to be an ornithologist to pursue this hobby, but you soon will be, if you keep it up. The birds will see to that. And the government will see that you get started right; will give you a permit to trap birds in or out of season, and will supply you with officially numbered alum- inum bands for marking your birds, provided you agree to band at least one bird a year and send the record to Washington. ‘It is easy to become a bird bander. All that is needed is the government permit and a trap that can be made at home. The U.S. Biological Survey, realizing the scientific value of banding, How the bird is held for banding, without injury, in the left hand while the small about its leg with the right hand. Note band on left leg of this brown thrasher can win personal friends among all the other wild birds that roost in your trees or hop about your grass. Finally, you may be surprised to learn that some of your new friends may return to you year after year. You may be surprised, too, when you discover that birds and human beings have much in common. You will find that each of your bird triends has a distinct person- ality; that some are affectionate while others of the same species are aloof and suspicious of you; that while most of them follow well defined habits of the species, some, like people, have amusing idiosyncrasies; that mother love is so strong in them they will adopt fledglings, and that the mother birds, like human mothers, have their worries in proper care and feeding of their babies. You will even find if you want to delve into their family life, that your beloved band is fastened now is experimenting with vari- ous types of traps at Washing- ton, D. C., and will supply full directions for making them. The ease with which fascinat- ing knowledge of bird life may be gained by any one is illustrated by the experiences of S. Prentiss Baldwin, of Cleveland, O., pres- ident of the Inland Bird-Banding Association, which covers the middle western states. Mr. Baldwin maintains two big sta- tions, one on a farm near Cleve- land and one on a plantation at Thomasville, Ga. He started banding birds a few years ago as a sport; today he is a recognized authority in ornithology. You can do the same. By setting up an inexpensive trap in your back yard to catch birds for banding, you can make - friends with the robins that re- turn to your yard every spring. You can know them personally. You can learn to distinguish your robin from the robin that . calls at the house next door. You This flat net type of trap can be made SE by tacking wire netting over a shallow frame. dropped, the birds are drivén through a passage into the small gathering box shown at the left After the trap is Fascinating Hobby of Important Scientific Value ae 7 % * . ‘e , \ NS A AS — ©vU.& vu. Jenny Wren and her mate are frequently divorced. This failing of wrens was never discovered until the birds were banded, until their legs were tagged with numbers by which ornithologists were able to check them when they changed mates. The method of catching and banding the birds without injury is a simple one. Two types of traps are shown on these pages. When the trap is baited with fine grain or bread, the bird will enter of its own will. Then it can be driven into the gathering chamber. In removing a bird from the chamber grasp its head between your first two fingers. It will use your little finger for a perch and will remain quietly. Using both hands, turn the bird over, securing its head with the little finger and grasp the left leg with the first two fingers. Then adjust the aluminum band about the leg, pressing its split edges together ‘with a pair of pinchers. To release the bird sim- ply open your hand, leaving the bird lying on its back. When it finds it is free it will fly away. Interesting new facts are being revealed every day by American bird banders. It may be that the age-old mystery of what becomes of the chimney swift in winter will soon be solved. In fact, the very band you place on a bird with your own hand may bring the solution. Every fall, flocks of swifts drift southward until they gather in innumerable hosts on the northern coast of the Gulf of Mexico. Then they disappear. If they dropped into the water or hibernated in the mud, as was believed of old, their obliteration could not be more complete. Along about the last of March each spring they suddenly re- appear on the Gulf Coast. But just where they spend the winter is still their secret. Scientists believe our swifts winter in South America, where many of the migrating birds from North America go. But the fact never has been proved. The finding of a swift in the winter i a late i Lee Toa atlas Let ic ns meegateny enero see ~ n= enn a a

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ee tn eee s4 time will solve the mystery, provided. the finding is reported. If the bird is banded with the mark of the U. S. Biological Sur- vey it is more than likely to be reported. If you doubt your ability to band birds successfully consider the experience of L: B. Talbot, of the New England Bird-Banding Association, and take heart. Last year he banded his first bird at Mr. Baldwin’s Thomasville station. Within a month he had banded 313 new birds and had trapped 43 “returns” — birds that had been banded in pre- vious years. In all, he handled 1804 birds in that month, including “returns” and “repeats” —those that went back into the traps on the same or succeeding days. Keeping Records It is from the returns that all government data about banded wild birds is obtained. Each bird banded is numbered and a record is kept of its movements. The age of blue jays, for instance, was learned in this way. No. 1916, a blue jay, was first banded in March, 1916, by Mr. Baldwin at his Thomasville place. The bird was trapped again in February, 1920, and a third time in March, 1922. Since the jay originally was caught in its first year, the rec- ords proved that the bird had attained an age of at least six years. This fixing of the age is an im- portant item in bird study. It shows how long the year’s hatch of any species may be ex- pected to live. In con- junction with local bird censuses now being taken it will help give an ap- proximate total of the birds in the United States. Birds Return Another interesting re- turn record, one of sev- eral which have proved conclusively that birds return to the same place year after year, was made on the farm near Cleveland. In June, 1916, No. 38461, a chim- ney swift, was caught in the north chimney of the farmhouse. In June, 1917, and June, 1919, the same swift was recap- tured in the same chim- ney. And this bird had ‘spent five months out of each year in its secret hiding place below the equator! The returns to the traps also have served to reveal the personalities Popular Science Monthly - Ill., has had some interesting experiences. No. 17042, a white throated female spar- row which has returned to his traps on * numerous occasions, always has shown an unusual disposition for tameness. Like most chipping sparrows caught in the traps, she likes to be cuddled. Recently, when be- ing released from the trap, she flew to a bush six feet away and from her perch quietly watched the banding of four new birds. . To release a bird simply open the hand, allowing the bird to lie on its back. When it dis- covers it is free it will fly away of its own accord. The brown thrasher shown here evident- ly is taking its own time to get away How to hold the bird for examina- tion. With its neck held firmly but gently between the first and second fingers, the bird will use the other fingers for a perch. This mourning dove is not at all fright- ened in captivity To change the posi- tion of a bird while handling it, pick it up by the head. In this position, strange to say, the bird remains quiet and unhurt. Notice how calmly this chimney swift is taking the operation of individual birds. In this connection William I. Lyon, of Waukegan, S. Prentiss Baldwin, on, scattering bait for a double funnel trap of wire netting. The birds follow a trail of crumbs into a chamber in the rear, where they are captured In contrast to her behavior, No. 17070, a male of the same species, is a fighter of unusual ability and proclaims it in a very loud voice. He starts his challenging ag soon as a hand reaches into the trap. When the hand approaches him he attacks, pick- ing the fingers with all his might. He never gives up the-fight until he is released; then he flies to the nearest branch to sulk and scold. Mr. Lyon has had the opportunity of watching a real tragedy in bird life. In ob- serving a pair of banded flickers and their. young, he discovered that a screech owl had made a nest near by. Fearing that the owl would interfere with the young flickers he robbed the owl’s nest and removed her to a spot some distance away after banding her. Strange Habits Learned A few days later he discovered the oul had returned and had invaded the flicker nest. He promptly threw her out. This performance was repeated for several days but the owl persisted in staying in the nest. She did not attack the young flickers; on the contrary she brought the birds she had killed for food. Although her foster fledglings would not eat the food, the owl kept it up until they were old enough to fly away and desert her. This is believed to be the first official record of bird kidnapping. One bird bander had a robin that became a pet from frequent trappings. This bird developed a taste for ice cream and would wake up as late as 9 o’clock in the evening to eat it if it were offered to him. Another enthusiast, Dr. R. D. Book, of Corning, Ohio, has taught wild birds to eat various foods they were not used to. He has derived considerable amusement from watching them eat macaroni, shaking it as they would shake a worm to “kill” it. Dr. Book also had an interesting experience with a female titmouse that was hatching a brood. He had banded this bird and her mate, and they had become so well ac- quainted with him that the male would alight on his hand to eat pie crust. The female craved the crust and would leave her nest and cry for it until her mate carried it to her. This he always did before eating any himself. But after the eggs were hatched the mother bird, though coaxed by the male, never would touch the pie crust again. Saving the Birds And so it is that bird banding every day is re- vealing new facts about the life and ‘habits of in- dividual birds. What is the purpose of it all? Aside from the fasci- nation of nature study, the chief purpose is bird conservation. Ornithol- ogists hope soon to com- plete an approximate census of the birds in the country. formation they will be able to guide intelligent legislation for the pro- tection of birds and avert another tragedy like the extinction of the Ameri- can wild pigeon. They hope to preserve the birds who are aids to mankind, including the insect destroyers that rid our farms and forests of destructive pests. Xs With this in- § ‘ é f I ee —— — ee

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he owl flicker This al days ie nest, rs; on he had foster he ow] n to fly d to be ping. yecame is bird would vening ook, of ; to eat o. He t from ig it as it. Dr. erience ching a nd her ell ac- would The 1 leave carried . eating atched e male, in. irds at bird y is re- s about ts of in- What is all? e fasci- » study, » is bird rnithol- to com- oximate is in the this in-- will be elligent he pro- id avert like the Ameri- They ve the aids to ing the that rid — rests of Revolving Lamp Shade Is Novel Advertisement ARCHMENT lamp shades, which lately have achieved wide popularity in the home, are employed by an Indian- apolis company as an advertising novelty. The illustration shown here indi- cates how a parchment shade may be used in advertising a brand of cigars. On the oppo- site side of the shade appears the name of the cigar, which is made to revolve into view by the heat of the in- candescent lamp. The advertising lamp is intended for use in store windows and in soda fountains, on cashiers’ desks, restaurant tables and other places where the attention of the passing public will be attracted. Parchment lamp used | as cigar advertisement Popular Science Monthly Army Airplane Picks up Messages from Ground SPECTACULAR demonstration of the employment of airplanes to co- operate with the infantry by picking up messages from the ground and delivering Bathtub for Baby Folds into at Cradle VEE everywhere will be inter- ested in a new combination baby’s bathtub and sea invented by Mrs. Charles Dancy, of Chiswick, England. At the left the device is shown in use as a tub. When folded, it forms the cradle at right. Philadelphia pails Wrecked by Rainfall HE wrecking of the building shown at the right is almost directly trace- able to a gentle rain- fall in Philadelphia recently. This lumber store- house had a flat tar and gravel roof and a drain pipe that was stopped up. Tons of water from heavy rains had accumu- lated on the water- tight roof, having been impounded within walls of ma- sonry that rose about three feet above the roof surface. A slight storm added enough water to that already there to cause the beams and joists.to give way. Building detnailabiod by the coulgien a water on its roof them, was witnessed recently at Brick- fields, Plymouth, England. The photo- graph shows a plane about to pick up a message attached to a line. Illuminated Bonnet Shaped Like Capitol Dome N ILLUMINATED bonnet in the shape of the dome of the state capitol at Sacramento, Calif., was an advertising oddity seen by tourists in California re- cently. The hat was worn by Miss Eleanor Posey, a native daughter of Sacramento, to The lights are operated by a small dry battery, with push button advertise the beauty of her city and of the Sacramento Valley. The hat is surmounted by an orange colored electric bulb, while inside are a series of lamps that give the entire crown a soft, blue glow. The lights are operated by a small dry battery and a push button - hidden in the loose sleeves of the wearer’s dress. The wires also are cleverly con- cealed in the garments. 6 bw editor will be glad to supply, wherever possible, the names and ad- dresses of manufacturers of devices men- tioned in Popular Science Monthly. e Bn pci lien ia ie ete en RS sina, ye eR ct ED RAE AEG eR eh ete A * Ap pierre reine a eet ae nate haber Lie eam oneness { } Rpniei asinine: wv ae ee nee

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# 4 4) + e f eS re. | 4 4 | # 46 Popular Science Monthly Hand-Driven Race Horses Run on Monorails NOVEL horse racing amusement de- vice recently introduced at Ocean Beach, Calif., consists of a series of wooden steeds running abreast on tracks and pro- pelled by the riders. The thrills and ex- citement of real horse racing are duplicated as the amateur jockeys travel the 500-foot course on steel rails. The horses running on four parallel mono- rails are propelled by moving back and forth two levers that operate the driving mechanism. Old-Fashioned Bell’ Pull for Electric Switch Gain old-time bell pull has been revived recently as a home decoration to take the place of the somewhat unsightly but- tons on the ordinary switch plate for turn- ing electric lights on and off. The switch is turned by pulling a tasseled cord. A pull switchss the electric lights on or off on the decorative cord Above, horses lined up at the starting platform. At left, propelling a horse along the rail by pushing hand levers Centrifugal Honing Tool Grinds Auto Cylinders A HONING tool for grinding motor cylinders, which requires no abrasive materials, liquids or lapping compounds, 5 inches in diameter and which is self- ABRASIVE PRESSURE APPLIED BY CENTRIFUGAL FORCE END VIEW EXPANDED centering and self-align- ing, has been developed by a Chicago manufac- turer. The stones used re- move metal from the cylinders without load- ing, and polish the sur- face in one operation. Centrifugal force devel- oped in rotation causes the parts to adjust themselves to the size of the cylinder. The tool is driven at a speed of from 800 to 1100 revolutions a minute and can be operated by a portable electric drill, stand- ard drill press or honing machine. ‘SIDE VIEW EXPANDED Ancient Indian Workshop Found at Dam Site ONSTRUCTION of a dam across the Susquehanna River near Conowingo, Maryland, is speeding up an archaeological investigation of a prehistoric Indian work- shop on an island eight miles above that place. For years John L. Baer, of the U. S.. National Museum, has been seeking the solution to the mystery of curiously wrought stones found in abundance there. “Banner stones,’”’ as the specimens are called, are believed to have been ceremonial objects carried by the Indians. They are unknown west of the Mississippi, but in New Jersey they have been found under other Indian material which indicates that they are very old. They probably were intended to represent birds and butterflies. Metal Shield Aids Typist in Making Erasures T° AID the typist in making erasures when a carbon sheet is used in the typewriter, a newly invented metal shield is inserted be- tween the first sheet of paper and the carbon. Often, when carbon sheets are used, the type makes _impres- sions in the white paper that are difficult to erase. The hard metal surface of the new erasing shield tends to iron out these indentations during the process of erasure, forcing the ink back to the surface where it can be re- moved easily. The back of the shield is covered with a felt.pad that rests against the carbon sheet, distributing the pressure evenly so that the carbon will not blur the duplicate paper. j How the metal shield is inserted | Radio Set and Phonograph which automatically fits itself without ad- justment to any cylinder from 2 13/16 to \ Combined in Lamp ‘SAN INGENIOUS combination table lamp, phonograph and radio outfit has been perfected by F. W. Hochstetter, of Dayton, Ohio. The same magnetized diaphragm that is used in the loud speaker when the lamp is employed as a radio receiver, will play phonograph records when a needle is in- serted. This diaphragm resembles a camera shutter in form and may be opened ° and closed to regulate the volume of sound. The lamp is of copper and ‘ with the elec- tric wires serves as an_ aerial when the outfit is used for radio a reception. The ai crystal detector receiving _ set, for which no s batteries are required, is contained in the spacious pedestal of the lamp, as is also the phonograph mechanism. The base of: the lamp is designed to serve as a sound box. This diaphragm regu- lates volume of sound “a The inventor, F. W. Hochstetter, operating his combination lamp, pho- nograph and radio receiving outfit Con Cc OR ne kitche Gilmo cabine contai food a The and cé suffici for al small party’ “Ms

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ist asures in the shield table outfit etter, hat is mp is play is in- es a pened ae Compact Auto Kitchenette Convenient for Tourists OR the automobile tourist, one of the new conveniences is an ingenious auto kitchenette invented by Miss Lou Shields Gilmore, of Los Angeles. It consists of a cabinet attached to the running board, containing a refrigerator, compartments for food and dishes and a water tank. The entire outfit weighs only 55 pounds and can carry ice enough for two days and sufficient food to supply a party of five or so for a longer period. With the addition of a small oil stove, the camping or touring party’s equipment is complete. ‘‘Machine Gun’’ Duplicator Saves Typist’s Time TT? PREVENT waste effort and dupli- cation of work in the writing of busi- _ ness forms—invoices, orders, requisitions, bills of lading and similar records ordinarily requiring many carbon copies—a rapid fire duplicating machine has been perfected by a nationally known manufacturer. Instead of making many changes of car- bon sheets and cut forms, with this machine the operator may load up once and con- tinue uninterrupted until the work is com- pleted. The manufacturer compares the opera- tion of this device with that of a machine gun. The machine has a “magazine” of 1000 sets of form and 750 feet of carbon paper. It permits the typist to use in actual writing the time ordinarily lost in prepar- ing to write. Tar E1rreL Tower will last for.23 years more, according to engineers who recently examined its stability as the result of a report that it was falling down. Popular Science Monthly Portable Factory Elevator Lifts Loaded Skids NEW time and labor saver for fac- tories where heavy material is carried . from place to place is an elevating truck that can lift entire rolling platforms and their loads to a height of five feet. The plat- forms are lifted by an elevating shelf run- ning on a truck framework and driven by | an electric motor. “aR The upper photograph shows a skid, fully loaded, picked up by the elevator truck. Below, the skid and its load elevated for discharging Speedy Fighting Plane Has Novel Wing Design NEW high-speed airplane of the fight- ing type, which is expected to beat all records in aeroplane performance, has been completed for the British Air Ministry. Its outstanding feature is the unusual wing shape, thin at the center, thickening to- wards the inner third of the span, and tapering finally off to a fine line at the out- side. It is operated by an air-cooled motor. The new machine embodies the advan- tages of the cantilever and braced types of wings without their disadvantages. The bracing has been reduced to a minimum, for only two small steel struts are fitted at each side. Where the struts are joined to the wing, the section of the wing is thickest, since the greatest stresses occur here. Where the stress is less, the thickness of the wing has been reduced; for the thinner the wing, the greater its efficiency. Both fins and rudders are cantilever surfaces. An air-cooled engine developing 400 horsepower is used in the new machine. In recent official tests, the engine broke all endurance records for air-cooled engines, running for 150 hours, including a non-stop run of 50 hours. Fitted to a modern fast scout, this is equivalent to three trips across the Atlantic. After the test, the engine was dismantled, and the maximum wear on any part was found to be less than one-two thousandth of an inch, proving that aircooled engines, even of very great power, can safely be fitted to airplanes serving long distance routes. As an aircooled engine is much lighter than a water-cooled one, and does away with radiators, water piping and tanks, a great saving in weight can be effected, it is claimed. Doubtlessly airplanes of the future will be propelled by aircooled engines. Front and rear views of the new plane, showing tapering design of wings

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oR SENS ate pee Ht ee $5 RARE MINT OE es eas tas TE

Fe Ris asthenia 5 I UT - aoe 2 Sr SET SS nie 48 Popular Science Monthly One-Man Bus Has Periscope Sight

Ra secaiplenee with a periscope, a double- deck omnibus that may be operated by one man successfully has been designed and built by a. New York inventor and has been placed in regular service. The vehicle is of the pay-as-you-enter type, a coin box permitting the driver to collect fares. A periscope directly in front of the driver’s seat enables him to view all parts of the upper and lower decks of the car, and to see signals waved to him by the passenger. There also is a telephone beside him through which he can make announce- ments to the passengers. A safety automatic door by which pas- sengers may leave the car from the rear is zontrolled by a lever at the driver’s right hand. John Catoff, who was associated with the

Clean Shave in the Dark with This Safety Razor EE PaIGNeD especially for use by travel- ing men, a self-illuminating safety razor makes it possible to shave in the dark. In the handle of the razor is a tiny elec- tric bulb, encased in a rubber holder which prevents dampness from rusting it. The lamp is adjusted so that it always throws its light on the spot where the razor is cut- ting. A clean shave in pitch darkness is said to be possible with this device.

A small electric lamp in the razor illuminates the face of the shaver

At the left, the one- man double deck bus, showing auto- matic safety doors and the periscope, through which the driver sees passen- gers on the upper deck of the car Below, the driver’s seat, with door con- trol, coin box and periscope sight

designer, Emil Leindorf, in making altera- tions to the original model, is shown here in the driver’s seat.

nl SLIDING | @ SLEEVE | F if RUBBER _ AIR BAG 5 * Road New Shock Absorber Has Rubber Air Cushion A* EFFICIENT and inexpensive pneu- matic shock absorber for light cars, perfected in Los Angeles, differs from other designs in that it replaces the usual moving piston with a rubber cushion containing air under pressure. The sectional view of the shock absorber above shows the construction. casing or cylinder is attached to the spring shackle, while a sliding sleeve is bolted to the axle. This sleeve merely acts as a guide and container for the air cushion. The cushion bag is built up of gum stock and cord fabric. An ordinary tire valve at the upper end of the shock absorber makes easy the infre- quent pumping up. A special fluid is in- jected to prevent oxidation from the inside. Pressure is maintained at from 80 to 100 pounds, according to the weight of the car. When the cushion becomes worn, it can be replaced easily without use of wrenches and without jacking up the car,

Ponn lar Gaianna Manthle<, An outer .

Surveyor Maps as He Goes With New Instrument A FRENCH inventor is responsible for this ingenious surveying instrument, . which establishes lines and slopes, measures distances without use of a tape and permits the surveyor to draw map as he proceeds. The surveyor may take his sights through the vertical tube in any direction without moving around the table. This is made possible by a complicated arrange- ment of prisms and lenses within the in- strument. The instrument is moved into line by a finely-adjusted milled head. When a line is established on a rod, a ruler at the side of the box guides the surveyor in laying it out on his board. Since the lines are drawn on paper which is ruled to scale, they . show distances with sufficient accuracy.

Spring Guard for Punch | Press Saves Fingers cake of Post Office Department workers employed in the manufacture of mail bags are protected by a spiral spring - guard from injury in punch presses used in inserting eyelets in the heavy canvas. The guard surrounds the punch and moves in advance of it, giving warning of the descending stroke.

spring guard descends ahead punch, protecting the fingers Fe. A of

If al an ave the lif child i Am« so con in a tl The Unive source death if we. care hardly have | our be of ow relate the g leaves We of tee With« the f canno stoma Poo:

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;0eS ; le for ment, . sures armits eeds. sights ection ‘his is ‘ange- he in- i into When at the laying es are cy. ch | tment acture spring sed in: 1 and ing of , they. she scant) CER Ne i a ARS Popular Science Monthly Blindness Lurks in the Teeth How Science Has Restored Vision by Uprooting Hidden Poison Factories eee even blindness and death. HYSICIANS to-day agree that .decayed teeth and infected gums may cause serious diseases, In the following article a national authority on the relation of teeth to health tells what science, with the aid of the X-Ray machine, has learned about the poison factories hidden in the roots of our teeth or around the margins of our gums. He tells why scrupulous care and repair of teeth is one of the most valuable forms of life insurance. By Edwin F. Bowers, M.D. Noted American Authority on Teeth and Health OUR hundred million defective teeth F exist in the United States—about four defective teeth to each person. If all these teeth were cared for properly, an average of 10 years would be added to the life of every normal man, woman and child in the land. Among school children dental disease is so common that only about three children in a thousand have perfect teeth. These recent estimates by the Columbia University School of Dentistry reveal a source of untold disease, misery and even death that might be prevented absolutely if we as a nation would learn how to take care of our teeth. Their importance can hardly be over-estimated. For scientists have proved positively that the health of our bodies depends largely upon the health of our teeth. In fact, so closely inter- related are teeth and health that not even the greatest expert can tell where one leaves off and the other begins. We recognize, of course, the importance of teeth in preparing food for digestion. Without proper breaking up of the food, the digestive juices cannot attack it and complete stomach digestion. Poor Teeth—Bad Nutrition Poorly prepared food—poorly prepared because of bad teeth or lack of teeth—thus may be con- sidered as a primary cause of faulty nutrition, resulting in ane- mia, neurasthenia, and the host of symptoms that follow chronic in- digestion and auto-intoxication from intestinal absorption. There is a very close relation, too, between decayed teeth and a large number of diseases that ap- parently have nothing to do with the teeth, such as ulcers and can- cers of the stomach, rheumatism and diseases of the kidneys. Pathologists tell us that, in many instances, the germ or strain of bacteria found in a diseased appendix was first developed in an infected tooth or an abscessed gum. The infected germ is carried in the blood stream, until it finally lodges in the vulnerable appendix. The relation of decayed teeth to decayed lungs also is a most intimate one. We are spending much _ time, money and thought upon tuberculosis and its pre- vention; yet how many of us realize that many Katherine Bryden, of cases of tuberculosis can Mo fe inn be traced directly to teeth caused total malnutrition caused by blindness and finally improper chewing of the nervous _prostration. food, or from the direct infection of diseased mouths. The germs of tuberculosis almost always enter the sys- tem through the mouth and the breathing passages. Therefore, bad mouth conditions are a fertile source of aid to the ravaging germs of tuberculosis. Many cases of mouth-breathing and ade- noids arise because of neglect of brush, tooth paste and elbow grease, persistently applied. Ulcerated tonsils and swelling of the glands of-the neck, and those very seri- ous diseases of the cavities of the facial bones (sinus abscesses) develop quite fre- quently from an infection of the teeth. In fact, the malignant germs, breeding in infected teeth and gums, together with the poisonous products they engender, may be Extraction of teeth re- stored sight and health absorbed into the blood, or the lymph stream, and thus be carried to every cell in the body. The damage they may do can be measured only in terms of their own harm- ful activity, plus the lowered resistance of the tissues in which they finally lodge. Even total blindness has been traced to poisonous conditions of the teeth and gums. In many instances, perfect vision has been restored by the correction of abnormal oral states. Among a number of such cases brought to my attention is that of Miss Katherine Bryden, of Grantwood, N. J. Miss Bryden was 23 years old last May. Until 12 years ago, she enjoyed perfect sight in both eyes. But in November, 1911, her vision gradually faded, until final- EYELID NERVES \ ly, she became totally blind in the right eye, and retained hardly more than perception of light in the left. Three years ago, Miss Bryden’s health failed utterly. She suffered from nervous prostration and was rarely free from “colds” and throat trouble. Appetite and nu- trition were affected to such an extent that she lost more than 30 pounds in weight. Sight Is Restored Finally, Miss Bryden was ex- amined by a New York specialist in oral surgery and an authority on X-ray diagnosis: He made a series of X-ray photographs of this patient’s mouth. Numerous ab- scesses, as shown on page 50, were revealed. Extraction of all the upper teeth was advised, The results of this extraction were almost miraculous. The patient’s vision improved imme- diately. Her throat trouble van- How the nerves of the teeth, eyes, eyelids, nose, jaws, lips and tongue are interrelatéd through the trigeminal, or fifth nerve, is shown in this diagram i > ee / ished and she gained steadily in weight, in appetite, and in her ability to digest and assimilate food. Her bodily resistance has weet ie ih a Gt a a nak Gch AREY RNS ra Nn Be a Ty ba — ie a aorar ae : ome : 2 ERO at wenpimcneiepe

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| i] 3 1 ci eS a Eerea tS My Ee SANZ. ry be en 50 been so enhanced that she hasn’t had a ““eold’”’ for upwards of two years. The explanation for this miracle of heal- ing is simple enough. The germs and poisonous products that had exerted their disturbing effect on the functioning capac- ity of the optic nerve were removed— therefore sight came back. At the same time, every cell and tissue in the body was relieved of an overdose of poison, and began to function normally. There is hardly an oral surgeon in active prac- tice who cannot detail cases that semingly have not the slightest connection with the teeth, yet which have made complete recovery, following the extraction of abscessed teeth, the clearing up and proper filling of infected root canals, the aseptic treat- ment of pus-laden pyor- rhoea packets, or the removal of a molar tooth—buried cross- wise in the jaw. Neuritis of years’ standing, sciatica, rheumatism, neuralgia, headaches, and many other painful conditions have been overcome almost as though by magic, when septic mouth conditions disclosed by the searching eye of the X-ray were cleared up. I recall another case—that of a healthy, robust looking man, who suddenly began to suffer from neuritis in the shoulder. He had tried all sorts of treatment, diet, mineral water, asperin, and rheumatism medicine, without relief. How X-ray Aids Dentistry Finally, an X-ray of his teeth revealed a huge abscess at the apex of a molar tooth that had caused “gum boils.’”” The tooth was removed, with the result that the very next morning this patient was relieved com- pletely. “The neuritis never has returned. The X-ray, without doubt, is the greatest scientific informer of modern times. It most nearly insures the certainty of deter- mining whether or not a focal abscess ex- ists at the root of a tooth, or whether a root canal is, or is not, properly filled. Nearly every dentist in active practice has seen openings at the roots of apparently sound teeth, through which there is con- stantly draining poisonous material. In- deed, careful investigators now contend that before the X-ray came into general use, fully 79 per cent of all root canals were im- perfectly filled. Faulty dental work—even work done conscientiously and painstak- ingly by able men—may prove a definite source of danger. Crowns that fail to fit the necks of teeth, badly adjusted bridge work, faulty abutments, overhanging fillings that constantly collect food particles and facilitate decay, almost invariably can be checked up by the X-ray. Care of the Dead Tooth In fact, there is no other method by: which a dentist can determine definitely the presence of an impacted molar or wisdom tooth, whether a root filling is perfect, or whether a tooth which he proposes to use as an abutment for a bridge is sufficiently sound for the purpose. Dr. Thaddeus B. Hyatt, of the Dental Section of the Metropolitan Life Insurance Company, has compiled convincing evi- dence of the value of the X-ray in deter- mining dangerous infection. In an examin- Poison Factories decay, sources of infection. Popular Science Monthly ation of 2537 teeth with non-vital pulps, 1404 showed pussy conditions in the tissues surrounding their roots. Strange as it may seem, it is now con- ceded that a dead tooth requires watching more than does a living, functioning tooth. With its source of nutrition cut off by local tissue degeneration, the dead tooth is much more likely to start putrefactive In this typical X-ray photograph of the teeth, the white portions indicate They are poison factories that undermine health changes in its surrounding tissue. Ab- scesses therefore are quite common in these teeth. Of 200 cases of dead teeth, examined by the experts of the Life Insurance Institute, In an early issue, an au- thority on the care and treat- ment of the eyes will tell how to safeguard the extremely sensitive machinery of vision in the wear and tear of modern life. 135, or 67 and one-half per cent showed evidence of infection. The total number of abscessed and infected teeth found among these 135 people was 205; while the total number of teeth improperly filled, and re- quiring immediate dental care, was 193. The bacteria that actually cause tooth A Model Operating 1* THE Veterinary School of the Uni- versity of Pennsylvania is an operating room for animals which is said to be one of the largest and finest in the United States. Here animals ranging in size from dogs and cats to horses and cattle undergo operations of all kinds performed by experts. a eee. lee: CUCU of the Teeth decay finally have been discovered ang isolated by Dr. F. E. Rodriguez, Captain in the Dental Corps, U.S. A. Dr. Rodriguez has isolated three types of bacteria with an exceedingly high acid: producing power. They produce acid fast enough and strong enough to dissolve the hard, limey structure of the teeth, and penetrate right through the enamel into the deep tissue. There is one phase of the subject of den- tal care which only within the last ten years has begun to be understood. This hag _to do with the rela- tion of tooth nutri- tion to food intake. Primitive man kept his teeth in very fair condition. This is proved by the condi- tion of the teeth in the skulls in the Brit- ish Museum and the Smithsonian _Insti- tute. They are wonderfully sound and free from evidence of dental decay. In a large measure, this was due to the fact that primitive man ate his food without cooking it. He tore the flesh from the bones and gnawed these bones in quite as workmanlike a manner as any dog would. Later on—a hundred centuries later, per- haps, he became a grain eater. And on the coarsely cracked grain, baked as hard as a rock in its red bed of embers, he gave his teeth still more exercise. At the same time, he supplied his body with the tooth and bone-making mineral salts which to-day are sifted out from our ground grain, and fed to cattle. Proper diet, with consistent dental care— which include a semi-annual cleaning of the teeth and gums—is a necessity. In addition, the secretions of the mouth should be rendered neutral or alkaline by the use of milk of magnesia, or milk of lime. A good dentifrice should be selected, and scrupulous attention should be paid to maitaining a clean condition of the teeth. Room for Animals The photograph below shows the depart-: ment of the operating room devoted to operations on small animals. The surgical methods employed by present day veterina- rians are said to equal those used for opera- tions on human beings. The chief surgeon is Dr. John M. Adams. ee Se ' i a =) Dogs undergoing operations in the operating room of the University of Pennsylvania Pc By Al OR F= siz Far W Kansas, Nevada will pus of time the da pioneer Indians for the the Ro The celebra 88th a the bi: Twain.

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. the birth of Mark Popular Science Monthly 51 Pony Express Riders to Race Over Plains, Reviving Frontier Days Landmarks of Overland Trail Tell of Scientific Progress By Al. H. Martin OR onethrillingmo- }|° + F ment this month six states of the Far West — Missouri, Kansas, Colorado, Utah, Nevada and California— will push back the hands of time and live again in the days when sturdy pioneers clashed with the Indians in the struggle for the empire beyond the Rockies. The occasion is the celebration of the 88th anniversary of Twain. To repre- the promise that the new service would carry mail from Missouri to the Pacific coast in eight days, instead of the three weeks required by the Overland Stage, in- augurated shortly after the California gold‘ rush of 1849." To the public 63 years ago this event seemed even more mo- mentous than the gov- ernment’s announce- ment, this summer, of a sent most fittingly the romance of bygone days a Pony Express race will be held from St. Joseph, Missouri, to San Francisco over the old Overland Trail, traversed by “Buf- falo Bill” Cody and the other famed mail riders of the plains. Hundreds of horses and scores of riders will be used in the 2000-mile jump, over which a mail service by relays of swift mustangs was begun 63 years ago, before railroads and fast mail trains conquered the magnificent dis- tances of the western plains. Wherever possible, conditions of the past will be duplicated. The riders of to-day, of course, will not meet the perils of attack by Indians and robbers and the going will be better from start to finish. Old Landmarks Still Remain Modern progress has supplied good roads dotted with guiding signs for motorists, bridges over streams which the riders of old had to ford, and well marked, protected passes over ranges of the Sierra Nevadas. But the path traversed will be the same old Over- land Trail which riders of the sixties used to negotiate in eight days. Many of the old landmarks still remain along the route, although their appear- ance has been changed interestingly by the march of modern science. Such a re- minder of the romantic days of the past is the “Pike’s Peak Livery Stable” in St. Joseph, Missouri, from which the riders started on their journeys west- ward. The building now is a machine shop! A landmark of Western progress. From this very building—the “Pikes Peak Livery Stable” in St. Joseph, Mo.—Pony Express riders started their swift journeys westward half a century ago. a machine shop. At the right is the old stage coach in which Mark Twain, Horace The building now houses Greeley and other celebrities rode. From eight to 10 days will be allowed for this month’s race, but the riders, aided by modern conditions, are expected to shatter the best records of those they will emulate. First announcement of the formation of the Pony Express was made in March, 1860. The whole country was startled by & A typical view along the historic Overland Trail. At the left is a rider of the plains with his swift footed mustang ©Paramount Pictures a mii im aft SE el OC nce iP 28-hour coast to coast airplane mail service. In the early days of the Pony Express, tremendous feats. of courage and endurance were required of the riders. The first riders of the service had to make a run of 55 miles before being relieved. Later the length of the successive relays was shortened to 33 miles, three*:horses being used. Riders carried the mails in two water proofed leather pouches, one swung in front and the other behind. Only letters written on the thinnest tissue paper were accepted, and the first postage rate charged was $5 an ounce. It was not exceptional for a single letter to carry $25 in postage, and for the two packs of the rider to contain mail representing postage of many thousand dollars. “Buffalo Bill’s” Lore Ride The longest ride ever made in the Pony Express service is credited to Buffalo Bill. When a lad of 14, he made a run of 384 miles through haz- ardous Indian territory, going on and on because his relief rider had been killed by Indians. This was four miles farther than the longest ride of ‘‘Pony Rob” Haslam, who made the fastest time on record—eight hours and ten minutes for 120 miles. In conjunction with the Mark Twain celebration, Admission Day and the 75th anniversary of the dis- covery of gold in California will be ob- served. The American Legion con- vention in San Francisco and a rodeo at Reno occur at the same time. With the varying activities of these events, westerners expect to present to the Eastern visitor a vista of the West of romance, at the same time showing scientific progress made by the settled West of today. Pepe yaar at et Vee i 4, 4 ‘ it pecan si oo LONE

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7 Hebei ese at eat ge mau setn sh x pet ) . 52 Popular Science Monthly =—, WITH CONICAL SURFACES WITH CYLINDRICAL SURFACES OF CONTACT OF CONTACT ny ANN “Ty Py Sperry, nN 7 ¢ YUU \@ ANUS Z SSS ROLLER CYLINDRICAL) BEARING BEARING Anti-Friction Roller Bearing Needs No Oil The diagrams above show the construction of a ball bearing, a conical roller -bearing and the newly invented combin- ation of roller and ball bearings. This new anti- friction bearing, the parts of which are pictured at the left, has been run 20,000 miles on an auto with- out the use of oil N ANTI-FRICTION roller bearing, which, it is claimed, may be used indefinitely without lubrication, recently has been invented by a New York engineer. The inventor asserts it is 70 per cent more efficient than any type now on the market. The new bearing combines the roller bear- ing and ball bearing principles. It consists of a straight sleeve which fits over a spindle, axleorshaft, and contains twosets of straight rolls, bearing rolls and spacing rolls. The bearing rolls carry the weight, while the spacing rolls or idlers, reduced to a smaller diameter, alternate and revolve in a direc- tion opposite to that of the bearing rolls. Side thrusts are taken up by rotating balls acting between disks and ball retain- ers, while bearing pressure acts on the rollers. As all parts are rolling there is no sliding and no necessity of lubrica- tion. The single bearing shown has been run 20,000 miles with no sign of wear. New Flashless Gunpowder "TE War Department has just an- nounced the successful development of a new powder for use in small arms and artillery. It is said to possess all the driving power of the type now in use, and at the same time it is smokeless, flashless and im- pervious to moisture. It will permit night firing without revealing the position of guns. Typewriter Carbon Paper Handled Automatically | igs a new device for conserving the carbon paper used in making ‘“‘second sheets” on a typewriter, the letter-head and second sheet are placed in the machine, and the carbon paper is fed between them auto- matically from the roller above. When a sheet is finished original and copies are removed simultaneously, leaving the carbon paper wound about the platen. Carbon paper is fed from roller Knock-Down Wheel for Quick Tire Changing NOVEL automobile wheel that will enable the motorist to change a tire— tube and shoe—in not more than 10 min- utes, and with no other tool than a small steel wrench, recently has been constructed. Nuts threaded to the ends of the spokes hold the steel rim in place. When these are Wheel with rim removed How the rim collapses loosened, the rim may ke removed, col- lapsed by the turn of a lever and the tire changed. A movement of the same lever makes the rim rigid when the new tire has been placed about it. Then the tire is pumped up immediately and the rim placed back on the wheel. The new tire in place Toothed Jaws in Vise Hold Round Stock 4 T° THE handy man about the workshop at home there come times when it is necessary to hold some round stock in a vise; yet the occasions for this sort of work are so few as to make it impracticable to own an expensive pipe vise. The device shown in the illustration be low slips into any wooden or iron vise, and will grip and hold almost any size of round stock. It consists of two pieces of steel, con- ‘cave and toothed on their inner faces and joined by a strip of spring steel which allows them to be brought close together or spread far apart. How the tocthed jaws fit into home work- bench vise, and hold round pipe for cutting ‘“‘Stainless Silver’’ Discovered NEW tarnish resisting alloy, called “stainless silver” recently has been discovered as the result of research in the laboratory of a firm in Sheffield, England. Canoe Carrier Folds Into Cushioned Back Rest AN INGENIOUS accessory for a canoe combines a wheeled carrier for use in making portages, a back rest for paddling, and a life preserver in case the canoe should upset. The cushioned device is fitted in the canoe as 4 back rest. When it is necessary to transport the canoe over land, the ap- paratus is placed beneath the bow, the wheels are attached and the canoe then may be wheeled along like a wheelbar- row. The cushions are filled with cork, making them useful as a life preserver. The folding device used as portage carriage and as cushioned back rest Sto, Batted Eipdebeente

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Popular Science Monthly

Interesting People and Their Work “He that works and does some poem, not merely he that says one, is worthy of the name of poet.” —Thomas Carlyle

“ LE dt ddchccccccdldcccecectccdcccccccdcdedededdeccedccseatmbsssis MAKING BLUDGEONS FOR BABE RUTH and other famous home run hitters of the major leagues is the pastime of Joseph G. Kren in a little shop back of his home in Syracuse, N. Y. The wood he uses in turning out base- ball bats for noted sluggers is second year growth ash, sun dried and weather cured. Kren is shown above at work in his shop

A DECOY ARTIST is Elmer Crowell, whose workshop is in the tiny hamlet of East Harwich on Cape Cod. His skill in duplicating the bodies of birds in wood and coloring them has won ' a for him a national repu- BUILDING TOYS IS HIS HOBBY. F. Tadema, > i 4 tation among sports- one of America’s most famous oil and watercolor : & . é “ Ave . . men. No two decoys _artists, is shown above with a miniature of the , é} diet be miaieas ace alee White-Henry-Stuart building, Seattle’s largest busi- / ig af ness block, which he is constructing with simple tools

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aD THESE TWO LOCOMOTIVES WERE BUILT OF SUGAR by Joseph Sommers, head pastry chef of the Hotel Astor, New York City, to adorn the table at a recent 100th birthday banquet of the Delaware & Hudson Railroad. The chef is shown above with his sugar models of the cld and new in locomotives. Note how intricate parts of the engine are reproduced in detail

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Sl ibe ape doen gy sapstie S teee mes POT PRRC Re AAR SE RNAI nF og Beste Rg MNT LRG es {priest By William H. Keats R. KEATS, one of the editors of the New York Sun, learned his tennis from a book on mechanics. Although he started to play the game after he was 30 years old, he has mas- tered it to such an extent that he now is rated as an exceedingly skilful player. He has witnessed every impor- tant tenniscontest at Forest Hills, | ST. Long Island, the tennis Mecca of -CONTACT America. What he says in the oF BALL following article about the me- chanics of the game comes with the authority of an expert. American lawn tennis—a sport that bids Ts is the greatest season in the history of * fair to rival baseball and boxing in national popularity and in world supremacy. In baseball, 72,000 fans this year witnessed the opening American League game in the huge new stadium of the New York Yankees. In boxing, 90,000 spectators saw the “battle of the century” between Jack Dempsey and Georges Carpentier at Boyle’s Thirty Acres in Jersey City. And now comes tennis, to thrill vast crowds wit) amazing exhibitions of scientific skill and sports- manship. At Forest Hills, L. I., the West Side Tennis Club is completing a great bowl of concrete and steel—the first stadium in America devoted exclusively to tennis—with a capacity of seating Here will be played this month 20,000 spectators. Mechanical -- ~or? wes. ee Te ae re P+ @0,,.-°°° the challenge round of the Davis Cup play, in which challengers of 18 nations will compete. Science Wins for American Athletes Americans rule supreme in boxing, baseball and tennis. Why is this? Simply because we are a nation of specialists, We put more brains, more psychology and more science into our play than any other people. No game affords a better example of this appli- cation of science than tennis as it is played by stars of to-day. They look upon tennis as a game of dynamic mechanics, and they study and play it on that basis. Kinetic energy, momentum, gravity, ballistics, elasticity, rotation, motion of translation—these terms sound like a list of chapters in a textbook of physics. Actually they are a concise compilation of the most important principles of tennis; principles that must be understood and mastered by any one who would excel in the game. The truth of this statement was demon- strated remarkably at Forest Hills last September when William M. Johnston, of San Francisco, who recently won the world’s singles championship at Wimbledon, England, met and defeated Gerald Pat- terson, of Australia, in the Davis Cup finals. In that game Johnston set a high water mark for mechanics and science as applied to sport. The little Californian played with such marvelous precision and mechanical accuracy that spectators al- most thought he controlled the ball by means of an invisible string. On one side of the net towered the power- ful Patterson, grim and determined, as he boomed his shots over the net at tremen- dous pace. On the other side of the net was “Little Bill” Johnston, quiet, cool and pale, yet brisk and businesslike in all his actions— Popular Science Monthly Kinks of ‘Tennis How Racket Experts, by Mastering Simple Principles of Physics, Have Won World Supremacy on Courts | ee ee © ‘ ‘ Popular Science Monthly NATURAL CURVE WITHOUT, _ SPIN an sx ACTUAL CURVE “fe ____ HORIZONTAL ty RACKET SLASHES ACROSS ae St BALL FROM LEFT 1 RIGHT Ae AS BALL 15 ASCENDING eBGcbys gee” ?” a> §=6Male. Suzanne Len- glen, the French girl tennis wizard, who holds__ the world’s champion- ship in women’s singles, completing a service stroke Mechanics of the American Twist ser- vice stroke. Slashing of the racket across the ball produces a double spin curve and a baffiing bound In the American Twist service, the racket moves across the ball from bottom to top and from left to right, as shown here. Arrows indicate twist of racket the possessor of the most scientific forehand drive in tennis. ; When the play began it seemed to me, as I sat in the grandstand, that the American could not possibly stand up before the Australian’s great speed and terrific service. But Johnston soon dispelled my doubts of his ability by returning Patterson’s most difficult shots with ease, often for clean passes or placements. In the end the Australian, although he possessed a world of speed and splendid control, was beaten by the one-sided score of 6-2, 6-2, 6-1. Science and a super- knowledge of the mechanics of the game had triumphed for the American star. The secret of Johnston’s success is con- trol of the ball, and the secret of control is spin. Control is just as important in tennis as it is in baseball. But the tennis player can stroke curves that no pitcher can pitch. In the so-called American Twist service, for example, the ball curves three ways. As it leaves the server’s racket it first describes’ an outcurve; by the time it has reached the net it has become a drop, and the bounce becomes an outcurve again. This wonder- ful service has revolutionized tennis. Maurice E. McLoughlin, ‘The California Comet,”’ and National Singles champion Se cl Rete RAMI in 19 expon this is “M plana whick of ab Twist ing ac and fi ball t recei\ right tilted point to lef left t natul surpr The} spinr S ee, es ae

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[Twist acket ball top right, rrows acket orehand D me, as merican ore the service. oubts of ’s most r clean ough he splendid ed score . super- le game ar. s is con- mntrol is n tennis s player n pitch. vice, for s. As it escribes- hed the bounce wonder- . : lifornia. ampiom Fa Gerald “Bill’’ Patterson, Tilden, 2d, Australia’s National New Star Champion i 6 in 1912 and 1913, was the most successful exponent of this stroke. In his own words, this is how he does it: “Mechanically speaking, the whole ex- planation of this service is that the axis on which the ball spins is tilted over at an angle of about 45 degrees. In the ‘American Twist’ this is produced by the racket mov- ing across the ball both from bottom to top and from left to right at the same time. The ball thus has a forward spin, from server to receiver, and also an impetus from left to right which makes it rotate on an axis tilted over as stated. From the server’s point of view it swerves in flight from right to left, but ‘breaks back’ on the bound from left to right. The receiver sees it curving, naturally, from his left to his right and is surprised that it ‘breaks’ directly opposite. The reason for this bound is that the ball is spinning in a plane which lies over at an . Se, angle of 45 de- a grees. When it iB strikes the earth _ . itstrives very hard, | \ due to its mo- tr \ * mentum, to Sy stay in the a Popular Science Monthly Mrs. Molla (> Bjurstedt “~~ Mallory, American Women’s Singles Champion plane of its rotation. Also this ball takes an erratic curve upon breaking, and is par- ticularly hard to meet squarely with the racket.” The mechanical secret of the remarkable control that is possible with this.service is the prolonged contact of the racket with the ball. The ball, which is thrown above the head and a little to the left, is struck a glancing blow while it is still traveling up- ward. At the same time the racket is wiped across the ball from rim to rim, left to right. Service Stroke Highly Important Once service was utilized merely to put the ball into play, but to-day service as played by Johnston, Patterson, William T. Tilden, 2d, R. N. Williams, and Vincent Richards has become an offensive stroke of great importance. Indeed, one _ break- through service means winning the set. What is the underlying principle that governs a “topped” or “‘undercut” tennis ball in its flight? Here is the answer of physicists: A spherical body, ‘rotating on its own axis, encounters more resistance in the air on the side that is moving forward than on the opposite side, and in seeking the line of the least resistance it is depressed slightly away from that direction. 3 In the theory of rotation, the maximum curve will be reached in a ball whose ro- tation is exactly equal to its forward motion. The back-spinning side of the tennis ball will encounter \ more or less friction, according AQ to how much its speed around \ its own axis is greater or The baffling effect of the revolutionary American Twist Ser- vice. stroke is shown above. Leaving the server’s racket, the ball describes a curve and drop. The receiver sees it curving and is taken by surprise when the ball, on the bound, suddenly breaks in the opposite direction. The reason for this bound is that the ball spins in a plane that lies over at an angle of 45 degrees ON Me gt a 6 Ce: tar The decisive Davis Cup Match between William M. Johnston, of Cali- fornia, and Gerald Patterson, of Australia, at Forest Hills, L. I. Popular Science Monthly “Little Bill’? Johnston, of alifornia, who recently won the world’s singles championship less than its speed in forward motion. Another stroke that is as important in tennis as the curved ball is in baseball pitch- ing, is called the Lawford stroke, discovered by an Englishman whose name it bears. This is the fundamental stroke of good ten- nis everywhere. It is a “topped” ball. That is, it travels with over-spin and its action is the same as a pitcher’s drop. The twist is given to the ball by a sharp upward glancing blow, the racket and arm following through and finishing high, on a level with the shoulder. No other stroke permits the player to exert such drive and still keep the ball in court. Another advantage is that on account of its spin it is an exceedingly diffi- cult stroke to volley. Tilden, Johnston and Williams put less top on their forehand drives than do McLoughlin and the two Japanese experts, Kumagae and Shimizu. Kumagae is noted for the accuracy and severity of his Lawford. One of the secrets of Johnston’s amazing skill is his forehand drive, which is the fastest and most “perfect stroke of its kind in the world. His racket follows through on the ball like the lash of a whip, and finishes around his body. “Follow Through’’ Is the Secret Tilden, Mrs. Molla Bjurstedt Mallory, and Mile. Lenglen, in giving mechanical twist to the ball, follow through to such an extent that the racket and arm wrap around the body. Kumagae, who is left handed, not only follows through, but his racket travels with such great speed and freedom that it finishes high over his head and describes two complete circles at the end of his stroke! As in baseball, golf and billiards, the “fol- low through” is the most important secret of suc- cessful tennis playing. It is the “follow through” of the racket that puts spin on the flying sphere and it is this spin that gives control. In other words, suc- cess in mastering the game of tennis depends largely on the skill in which the fundamental principles of mechanics are applied at the mo- ment when the racket strikes the ball. It is the study and applica- as tion of these principles that thakes worid’s champions. See Ped te IE act . SR eS ate Hed RIE PI Ns : iat) EER ESI Sh Se steams tiie ef ee Seine a ven : Rieti ai Bi or orm aaiets ep ateoenhemen ieee teneest sieht es inet pues ere tno a SRL a, Na Fits ae nae Se i" note tS

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56 Roller Skate Sailing New Sport in Germany AILING before the wind on _ scooter- roller skates is a new sport that has become popular on the streets and in the parks of Berlin, Germany, where it was introduced by an English inventor. The skates are made of light metal and have extremely large rubber-tired wheels, resembling the “scooters” so popular with American children. The skater stands on a small platform slung between the wheels, and the skates, strapped to his feet, are braced half way up the leg. The light triangular sail is made by stretching canvas on a bamboo frame. Ina stiff breeze a speed of at least 30 miles an hour is possible. Speeding with the wind, two roller skaters are propelled by one sail Tiny New Animal Swims in Drop of Water MICROSCOPIC animal about one two-hundredth of an inch long has been discovered by L. L. Woodruff, of Yale University, who has named it ‘‘Parame- cium polycaryum.” It is one of the one-cell forms known as protozoa. It moves about rapidly in a drop of water and feeds on bacteria. Strange Fishing Boat Made of Odds and Ends Y UTILIZING all manner of odds and ends such as can be found about almost any machine shop, an Italian workman has constructed a strange looking craft with which he glides along the Po River in Italy. The boat is steered by means of a bicycle handle connected with the rudder. With his feet the operator turns the propelling paddle wheels. A net suspended from a boom is raised and lowered by means of a rope that passes over a hand operated pulley. Made of machine shop junk, this novel boat i$ propelled by foot power Popular Science Monthly =e ~ World’s Largest Bass Drum Taller than Drummer [Ts largest bass drum in the world is eight and one half feet in diameter— taller than the drummer who plays it. The instrument is constructed on the de- sign of a smaller bass drum, from which it differs only in its proportions. To transport it along the street in a parade, the drum is mounted on a small carriage with heavy rubber tired wheels. As it is pulled along, the drummer pounds out a tune. Pocket Movie Camera Ilolds 81 Feet of Film HE development of small movie pro- jection for home use has led recently to the perfection of a pocket. movie camera, ideal for taking cinema photographs on the automobile trip. The camera holds 81 feet of film, and is said to produce motion picture photographs as perfect as do the movie cameras of regu- lation size. . Above, Miss Rose Sturtz is shown dem- onstrating the new camera at the Interna- tional Photographic Arts and Crafts Expo- sition in New York City. New Aerial Camera Takes Ten-Mile Picture IEUTENANT G. W. GODDARD, of the United States Army air service, jg shown below with the new aerial camer which he has invented and which he trieg out successfully in a recent flight in the vicinity of Los Angeles, Calif. The new camera is for mapping purposes, It automatically makes successive ex sures of uniform size on a film 390 feet long and six inches wide. The resulting picture, are joined together, as in ordinary aerig] photographic work, to make a topographic map. From a height of 16,000 feet a strip of land 10 miles wide can be photographed in a single exposure, en- Jo" Lieut. Goddard’s aerial camera ‘‘shoots” pictures through the floor of the plane abling the operator to map more than 1000 square miles in a couple of hours. The entire outfit weighs 100 pounds. New Active Volcano Found | in China Sea A NEW volcano has just been born. Pre- liminary reports have been confirmed by recent advices to the U. S. Hydrographit Office which gives the location of the vor cano in the China Sea near the coast of French Indo-China. Voleanie activity in this region is de clared to be something quite new by Dr. H. S. Washington, of the Carnegie Institu- tion of Washington. The volcano is now 97 feet high and in full eruption. Endless-Tread Auto Climbs the Steepest Grades Y SUBSTITUTING small endless treads for the conventional rear wheels, Andre Citroen, known as the Henry Ford of France, has produced a motor car which he says is capable of ascending any grade less steep than the side of a house. . Andre Citroen demonstrating the ing power of his endless tread auto climb- — Par VE] pre from Pp Die; juris com his | me! ried Te

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-- Paper Tees Aid Golfer to Drive Accurately | the golfer can afford to have his practice fling with these tees made The tees are made from stiff paper, and are so inexpensive that the golfer will not mind hitting them into space and losing them. They hold the ball always at the same height, thus assuring uniformity in ‘the drive, provided, of course, the stroke is always the same. from paper. High School Boy Graduated | by Wireless TH distinction of being the first student in the United States to be graduated by radio goes to Lester Picker, of San Diego, Calif. Confined to his bed by in- juries and unable to attend his high school commencement exercises, he broadcasted his graduation speech from his home. A receiving set with loudspeaker attach- ment, set up in the school auditorium car- ried his speech to the entire audience. Terraced Apartment House Planned by Architect FRENCH architect’s design of the apartment house of the future calls for a structure 10 stories high, built in receding terraces so as to afford light and air to every apartment. The three lower floors of the house are to be occupied by a gym- nasium, a swimming pool and other health and amusement facilities. © Courtesy Building Age Ten stories in receding terraces, will permit plenty of ‘light and air Popular Science Monthly BUCKING automobile which accu- rately imitated the actions of a lively bronco was exhibited recently at the National Western Horse Show in Denver, Colo. Bounding around the arena, the car at times lifted all four wheels in the air and came back to earth with a bang that re- sembled the attempt of an unbroken filly to throw its rider. The bucking action was produced by using wheels with eccentric hubs. Each hub was three inches out of center, giving the Bucking Auto Imitates a Broncho car an up and down motion as it covered the ground.. Since the wheels were not con- nected they seldom moved in the same phase and so imparted queer motions to the car. Whenever the wheels became synchronized, the auto was thrown vio- lently upward, causing all wheels to leave the ground. On a saddle fastened to a strut in rear of the car sat the buckaroo who experienced all the varieties of jolts that any horse could have given him. Zetia oo Prize Winnin Concerts by Radio L Sogeemscdes ZAGER, of Chicago, is shown above persuading “Baby Grand,” his prize-winning radio canary, to sing over the telephone. Long distance singing is no new feat for Baby Grand, which more than once has given radio concerts from Chicago broadcasting stations. Zager has trained the bird so perfectly that it will sing at command, a fact that was most important in maintaining the time ‘schedules at the radio stations where it performed. Zager breeds canaries as a hobby, often having several hundred in the attic of his home. He does not keep them in small cages, as is the usual way, but gives them relative freedom in large flying coops. The . sturdiness which his birds develop from the resulting exercise, he says, is largely re- sponsible for their ability as songsters. Birds from Zager’s cages have taken first prize in the Chicago show for the last two years, winning over 1,500-warblers..-_- Bird Cthee o The World’s Most Powerful - Machine Gun — "PRE most formidable enemy of the air- plane that has been developed is the new .50 caliber Browning machine gun, shown below. This weapon is the most powerful machine gun ever perfected. It fires a bullet weighing a quarter of a pound, and will fire 500 shots a minute. The maximum range of the gun is 9000 yards, or about 5 miles, and the caliber is such that one hit will destroy an airplane two miles away. The anti-aircraft tripod used will permit the gun to be swung through 360 degrees, and elevated from 15 degrees below the _ horizontal to a vertical position. The new machine gun on tripod, ele-

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dae ay ee sg a i Ne Se 4 5 ie a 9 i rs ht FY 4} \ ‘a Be i i t ah 4} bs H The Power of Auto-Sug gestion Success in Every-Day Affairs Can Be Won by Bombarding the Mind with Purposeful Ideas; How Ford and Marconi Did It } ; Professor of Physiological Psychology, Cathedral College, New York City HIRTY years ago Henry Ford com- pleted his first gasoline engine after working on it for two years. He found the thing would run when mounted in a buggy, but it wouldn’t back up. So Ford laid it aside temporarily. But for two solid years he kept thinking and believing that an en- gine capable of going forward and backward at the will of the driver was possible and that he could build it. In 1895 he went to work on his second gas engine. He had nothing to guide him but his own brain— and his brain, like every man’s, re- sisted new ideas. He had to build and invent at the same time. Many times he seemed to be at the end of his resources, but he stuck to his idea and after three years com- pleted the engine he had visualized —one that would go forward and backward. So was born the Ford automobile. Why Henry Ford Succeeded “This thing can be done,” he kept saying. “Iam doingit. I shall keep at it.”’ And this year the Ford plants are turning out something like 1,500,- 000 cars! Henry Ford’s career is the most striking example of auto-suggestion I know of. He had been called crazy. When he completed his first engine and found it unsatisfactory, he was confronted with what would have been insurmountable obstacles to most of us. Balked in his purpose temporarily, he kept thinking “It can be done,”’ and that thought carried him through all barriers; especially through his own mental barriers, which in- sisted there was no solution of his problems. For auto-suggestion, which is merely self- suggestion, means simply the ability to im- press an idea on the mind, and through the mind on the will. It means impressing that idea underneath the ordinary Barrier of opposition raised against the entrance of new impressions. All of us are born with what has well been Popular Science Monthly called negativism. Tella child to do some- thing and it will balk at once. We are will- ing to do the things that we ourselves think about, but when other people offer ideas we do not care to accept them until we have thought about them. This natural barrier against acting out the thoughts of others works very effectively. It is Nature’s way of protecting us until we have given a prop- Henry Ford stands today as one of America’s most striking examples of the power of auto-suggestion to accomplish. ‘The thing can be done. I am doing it,”’ repeated Ford nearly 30 years ago. This year his plants will turn out 1,500,000 cars osition due consideration before acting. Advertisers know that if you say a thing often enough, people finally will act upon the suggestion. M. Coué urges his patients to say to themselves in the early morning and late at night, ‘“Every day in every way Iam getting better and better.”” This repe- tition gets the idea into the mind in such a way that it can be acted upon. Ford’s problem was to get the idea of his gas engine impressed on his mind strongly enough to make him exert more effort of will than he ever thought hé had. He did it, and by succeeding in this first effort, trained himself for meeting and conquering future The Henry Ford of 1903, at the first lap of his spectacular career, driving his speed creation in which he won a thrilling race with the car of Alexander Winton in Detroit ‘his mind he is equal to his neighbor or busi- problems. The value of this early traini in self suggestion was demonstrated : matically when in 1920 and 1921, with assets of only $20,000,000 apparently available, he was called upon to produce $58,000,000 forthwith. Everyone knows of the re- markable fight that followed and of his final success in keeping the grip of Wall Street from his business. “I will run my own business,” Ford repeated. And he meant it, Auto-suggestion, either conscious or unconscious, carried him through, The idea of running his own busi- ness was so firmly fixed in his mind that, so far as he was concerned, there never was any question about the outcome of his struggle with Wall Street. The Habit of Failure ° | The reason most people would have failed where Ford succeeded is that they say they will or will not do something, with the mental reserva- tion that probably they will not be able to accomplish their purpose. When a person says “I’ll try,” failure already is in sight. In most, of us it has become a habit to pro-, pose to do things when we should purpose todo them. As a result we use only a small part of the powers — which we actually possess and we while. We gradually become in- ferior to our full selves. In other words, we allow our inferiority com- . plex to rule us. In the end we lose confidence. Socially we feel inferior to our friends or neighbors, or we feel ‘ inferior to our associates in business acumen. The result is that others take us at our own valuation, and before long we actually are inferior. Auto-suggestion is a good cure for this state of mind. A man has only to make up ness associate—impress it on his mind hard enough to stir his will into action—and he will climb back to where he was before his inferiority complex gained control of him. The power of auto-suggestion is just what M. Coué is using for the cure of all sorts of ills. This power, however, is not confined to curing ills. It can be mer never accomplish anything worth | Re wh applied Just ke someth to do i natura It w telling throug that is and it: Wh experi that v missic tried out st thing in 18 early two 1 noun miles not i met in de he k suce righ FE sup] and and ing ten on. me:

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Popular Science Monthly Repeating to himself that he is master of beasts, the animal trainer gains real mastery which, reflected in his face and movements, finally convinces the animals of its truth applied to all the ordinary affairs of life. Just keep telling yourself that you can do something and after a while you will be able to do it, if it is not entirely beyond your natural powers. It was Guglielmo Marconi’s habit of thus telling himself that he could send messages through the air without the use of wires that is responsible for wireless telegraphy and its offspring, radio. ef When Marconi, at the age of 16, began t experiment with wireless, he was convinced that wires were not necessary in the trans- mission of messages. For five years he tried to put his theories into practice, with- out success. But he kept thinking that the thing was possible and worked along until, in 1895, he got his first patent. With this early apparatus he could cover a distance of two miles. He was ridiculed when he an- nounced he could send messages nine miles. His native country, Italy, was not interested in his work and he met every possible discouragement in developing his apparatus. But he kept telling himself he would succeed because he knew he was right. Finding that he could get no support at home he took his theories and apparatus to England in 1896, and the next year succeeded in send- ing messages 12 miles. In 1898 he ex- tended his operation to 32 miles and on December 12, 1901, flashed the first message across the Atlantic. In 1908, when transatlantic wireless stations were opened for business, the world accepted the new method of com- munication as a matter of course, never stopping to think of the innumerable prac- tical difficulties overcome by Marconi or how he overcame them. To most people it seems an almost child- ish idea that you can just repeat something and have it produce ever deeper and deeper influence, but it is literally and practically true. The average animal tamer mentally repeats over and over again that he is master of the beasts and so gets to know it is true. And this gives him the determina- tion which, reflected in his eyes, convinces the animals he is their master. ‘ Some men, lacking confidence, wake in the morning with a tired feeling, reasonably sure that they will not be able to accom- plish much that day. And of course, they fail to accomplish. A man who fails to be- gin the day by saying to himself ‘I will do to-day what I wasnot able todo yesterday,” has not the heart to tackle his job properly. But if he has confidence in himself, it makes his work easier until it becomes a pleasure instead of drudgery. Further, he learns he has individuality. Many of us never learn this. We do things in the conventional way because we are afraid to be ‘“‘different;” afraid we will be laughed at if we allow our personalities free play. That is a fatal Less than 30 years ago Guglielmo Marconi was ridiculed when he an- nounced he could send messages two miles by wireless. Today, with the suc- cess of radio assured, he has just an- nounced the perfection of a new method for transmitting messages up to 2500 miles not only with-a:very much smaller amount of power and energy, but also cheaply than the ordi- + mistake. What if Marconi had succumbed to ridicule? I know an accountant who has risen high in his profession. He once told me that he started as a clerk in the offices of a large corporation which, had hundreds of em- ployees such as he. They were as much alike in their duties, habits and dress as peas ina pod. He was in a fair way to become - established in this class. Then he took inventory of himself and his job. He dis- covered that the reason he was getting $18 a week, the same as the others, was because there were so many thousands doing the same work in the same way that he could be replaced at any time, much as an auto- mobile part can be:-replaced, by a man just as efficient as he. He said to himself, ‘‘I’m different. I will not be the same.” He kept thinking this until he firmly believed it; then he quit his job. With confidence strong in him, he reached for a higher position in his profession and got it. He has been advancing ever since. Some persons who are afraid that strenuous effort will shorten life,could allay their fears by reviewing the lives of some of our great physicians. I made it a point 25 years ago to know well half a dozen of the older menwho were great workers in New York medicine. Among them were Stephen Smith who died at the age of 99 years and eight months; Thomas Addis Emmet, who died at 93; Abraham Jacobi, who was nearly 90 when the result of an accident took him away; William H. Thomson, who was well above 80, and J. W. S. Gouley, the distinguished ° surgeon, another of the octogenarians. Each one had been an intensely hard worker. These men gave themselves suggestions that warded off tiredness. They pushed through the barrier of beginning tiredness and used up the sum of their energy. In- stead of exhausting themselves, they broad- ened life and made themselves more cap- able, not only of greater work, but actually of longer life. Is YOUR memory poor? Next.month Doctor Waish will describe iri detail a series of simple daily exercises—a ‘‘daily dozen’’ for the mind—that will help you overcome this:serious-handicap.

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eo — Set ees cases os SEEN ERE oa = Tine aera eanden enti Po Popular Science Monthly Torsion Machine Tests Wooden Beams T° OBTAIN exact information as to the strength of wood used for such pur- poses as rudder posts, elevator spars and air- craft beams, the U. S. Forest Service has constructed an un- usual torsion testing machine in its labora- tories at Madison, Wis. The wood to be tested is fastened se- curely between two large disks, which are made to revolve in opposite directions, twisting the specimen under _ test. The amount of torsion, or twisting strain, which the wood will with- stand is recorded in terms of inches or de- grees of arc. DISKS REVOLVE IN OPPOSITE DIRECTION "WOODEN BEAM UNDER TEST my TORSION Y RECORDED a ci Am) yw. | COUNTERWEIGHT | Testing a wooden beam by twisting it between rotating disks Voices Trained by Breath Recorder A BREATH recording machine designed to teach actors, singers, and orators to sing or speak correctly and with maxi- mum conservation of energy, has been in- vented by a Viennese opera singer. An oscillating plate is suspended within a small horn, similar to the mouthpiece of a telephone transmitter, in such a way that it will vibrate when the sound waves of the. voice are directed against it. Vibrations of the plate are recorded by the movements of a needle on a dial, but the apparatus is so arranged that there is no movement of the needle if the breath is used correctly. This adjustment was obtained by observ- ing the effect on the machine of trained voices. Movements of the needle from the position of rest indicate the use of the breath in incorrect quantities. The person using the device perseveres with his efforts until the needle shows that he has mastered the use of his vocal equipment. ; T°? TRACE the migrations of fishes in Phonograph ‘Silencer’ Filters Out Scratches AN INGE- NIOUS “si- lencer” for pho- nographs has been put on the market recently by a Texas man- ——$} ufacturer. As shown in the il- lustration, the device is inserted between the nee- dle and the re- producer. Its design and materials are such that it filters out the scratching of the needle on the surface of the record, it js claimed, while reproducing the record with unimpaired volume and a sweet and natur tone. It may be attached to any make of talking machine using needles. Uncle Sam Tags Fishes to Trace Migrations the oceans, the Federal Bureau of Fisheries has marked with metal tags about 10,000 cod, pollack- and haddock. Dis: coveries about fishes’ habits are expected; Gal M* hobby Mackin a fish with metal tag Liviné Human Cells Dissected in War against Disease FASCINATING field of science which is expected to lead to highly im- portant discoveries in the war on disease has been opened recently by the perfection of an improved micro-vivisection appa- ratus with which living human cells, invis- ible to the unaided eye, can be dissected and studied. The apparatus was developed by Pro- fessor C. E. Thoraldson, of the department of zoology of Northwestern University. It is of brass, small enough to be held in the palm of the hand. Micrometer screws con- trol glass needles and pipettes which cut into a single living cell isolated in a drop of nutrient liquid under a microscope. The movement of the screws is measured in the thousandth part of a millimeter, yet it is always exact, controllable and free from vibration. By his device, Professor Thoraldson says it is possible at last for scientists to remove certain portions of a living tissue cell and yet keep the remnant living, so that its sub- sequent development can be observed. Through pipettes or glass tubes, certain chemicals may be injected directly into the protoplasm of the cells and their effect studied under the microscope. The appa- ratus also is said to isolate pure cultures of bacteria by a much more rapid method than any other previously devised. On the theory that once the complex Prof. Cc. E, Thoraldson at. work with. his micro-vivisection apparatus basic cell could be broken up for study the functioning of the entire body could be better understood, scientists have at- tempted for more than a half-century to devise a means of dissecting a single living organism. Prior to the development of Professor Thoraldson’s machine, their efforts were only partially successful and they had to content themselves with ob- servation of dead and fixed tissues. Since the functioning of a single cell may be taken as the key to all problems of animal or human conditions in sickness or health, scientists say that the Thoraldson apparatus provides means for research which may lead to the discovery of cures for diseases which always have bafiled physicians. The same cell, after dissection Living human cell under a microscope

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ng of the ord, it is cord with d natural make of les to 3 fishes in ureau of igs about k. Dis: »xpected; se tudy the ould be ave at- itury to le living ment of , their ful and vith ob- cell may lems of cness or raldson research of cures bafiled — Galloping Hobby Horse Is Propelled by the Feet ECHANICS have entered the nurséry and have made the time-honored hobby horse run with the speed of a bicycle while still main- taining life-like motion. A large rear wheelis propelled by the rider as he bounces in the saddle, pushing down with his feet on the stir- rups. The wheel is turned by a crank to which the wooden horse’s hind legs are fastened. The weight of the rider’s body, as he sits on the horse, forces the crank down, making a half turn of the wheel. The stirrups are formed by a cross-bar beneath the horse. When the rider shifts his weight to this bar, a lever action forces up the rear of the horse, making the other half turn of the wheel. As the toy rolls along, its ne: resembles that of a live horse. Kettles Made 1 @ from Pennies ¢ SING United States one - cent pieces as their material, two sheet- metal workers in New York City recently held a contest to determine which one could hammer out the smallest kettle. The results of their handiwork are shown in the illustrations. ' Two of the kettles are provided with tiny handles and with spouts that permit the passage of water. All three are so tiny that they can be held in the palm of the hand. Rubber Masks for Actors . Replace Stage Paint [NSTEAD of using paint, powder, lip sticks and eyebrow pencils to give definite character to the features, actors and actresses of the Staatstheater in Berlin eover their faces with thin flexible rubber masks representing the faces of the char- acters to be portrayed on the stage. Since the rubber clings to the face, the mask moves with the wearer’s features, pro- ducing smiles or other facial expressions. — nate Monthly . A Storebousl of N THIS room are filed the thousands of applications for patents registered with the United States Patent Office. As soon as an inventor sends in his appli- © U.: & a Saubabieel Ideas cation to the patent office, clerks go through the files in this searching room to ascertain whether or not application already has been made for a patent on the same device. Radio Champion Hears 35 Stations in 24 Hours ie ALWAYS has been a source of pride to be the only one in the world able to do something that no one else ever has been audacious, patient or original enough to do. As a result there are some very curious records. In Paris, in 1809, the famous Danes, Bap- tiste and Francois, competed in a race on the Place de |’Opera, in which both of them walked on their heads. The latest contest stunt is a “radio golf” endurance record established by Harold Stein of New York City. Sitting at his receiver for 24 hours, Stein brought in a total of 35 stations all over the U. S., Canada and-Cuba with a total of 30,000 miles for the period. champion Harold Stein, golfer,”’ lunches while he listens in “radio Auto “Squirrel Cage” Is New Thriller "T BRILLS a plenty are furnished for the spectator by the “Squirrel Cage,” a new daredevil stunt now being performed in leading vaudeville theaters. As the name implies, the idea of the new thrill producer is taken from the familiar The circular track revolves on roller bearings in a di- 4 rection opposite / to that of “ the car revolving wire cylinder in which captive squirrels do their daily dozen. This human “cage,” though, is a circular track of steel, 18 feet high, revolving on ball bearings when a tiny racing automobile is run within it. The revolutions of the “cage” are produced by the wheels of the automobile revolving in the opposite direction. A speed of 25 miles an hour is necessary before the ap- paratus moves fast enough to permit the driver of the car to loop the loop. This he does again and again, until the audience is held in a state of tension. Popular Science Monthlv Then, when the specta- tors are sufficiently keyed up, they are given their final thrill. A lever is pulled which locks the “cage,” the lower portion of the structure collapses, and car and driver are hurled into space. They are caught in a basket concealed from the audience in one wing _ of the stage.

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ee hc is ESS Sit. ORE TONE GER ‘ TZATENY SYRI eRe RIE Popular Science Monthly ©U.&U. World’s Most Powerful Broadcasting Station HERE is the giant transmitter of the new WJAZ broadcasting apparatus at the Edgewater Beach Hotel, Chicago, said to be the most powerful radio station in the world. Programs transmitted by this ap- paratus can be heard everywhere in the United States. Reports have been re- ceived that the station’s programs have been-picked up at places 3,000 miles away. This range of transmission is surpassed frequently, of course, by broadcasting sta- tions near,the coast, but a 3,000-mile range is extraordinary in a station located so far inland as Chicago. The WJAZ studio is on the ground floor of the hotel and is walled by plate glass, permitting visitors to see how the broad- casting is carried on. Radio Fan Installs $5,000 Apparatus at Home ROBABLY the most elaborate of all home radio outfits in America is that owned and operated by George Freisinger, of New York City, who has installed trans- mitting and receiving apparatus in his home. Being wealthy, he has spared no ex- pense on his apparatus. He has spent to date more than $5,000 in fitting out his station, the call letters for which are 2-ABT. Freisinger, who is a licensed operator, is shown below with his instruments. At the extreme left is a 300-watt transmitter, while mounted on the desk is a combination transmitter-receiver of the navy type, using 20-watt singer tubes for transmitting and a standard honeycomb regenerative hook-up with two stages of audio amplifica- tion for receiving. In the center is a special type of amateur receiving unit with two stages of audio ampli- fication and at the right is a three-stage power amplifier. Plain Teacups Serve as Radio Amplifiers | A® INVENTIVE radio fan has devised a surprisingly efficient loud speaker from his head phones and a pair of tea cups, as shown in the photograph above. The head set is connected with the amplifier and each ear piece placed into a teacup. He re- ports that a clear, bell-like tone of aston- ishing volume is produced. Loud Speaker Ou in Recruiting 4 as a stimulant to recruiting is being used with great success by the New York National Guard. The photo- graph above, taken at Thirty-fifth Street and Broadway, New York City, shows how it is done. Music from the big loud speaker always can be depended on to attract a crowd; then, when the crowd is large enough, a recruiting orator mounts the rostrum and explains to the assemblage the advantages of National Guard Service. Radio Secrecy Attained by ‘‘Scrambling’’ Device NE of the greatest problems of radio telephony—privacy of conversations —has just been solved by engineers of the Bell telephone system, through the inven- tion of apparatus that is reported to have worked successfully over a 30-mile stretch of ocean between Los Angeles, Calif., and Catalina Island. Radio. secrecy has been obtained, through an invention that “scrambles” the conversation at one end and “unscrambles” it at the hearer’s end. In other words, the radio talk becomes a jumble to any outside party who may try to listen in on the same wave length.

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eaker cups, The r and Te re- aston- ng is y the hoto- treet show ways owd; th, a -and tages radio tions f the iven- have retch , and ined, ” the bles” s, the itside same Popular Science Monthly Around the Radio Circuits with Jack Binns | Second Article: The Secrets of Reflex and Inverse Dabs This is the second of a series of three articles in which Jack Binns, our radio editor, is reducing. intri- cate radio circuits to first principles. Here he explains the fundamentals , on which radio frequency and reflex circuits are based, and shows the relation existing between these sup- posedly involved circuits and the simple vacuum tube circuit O THE majority of radio fans, the mention of “reflex” and “inverse duplex’”’ circuits conjures up visions of circuits hard to understand and still harder to design. As a matter of fact, these circuits can be mastered easily once the fundamentals are understood clearly. In the simplest type of vacuum tube set there are three circuits as shown by A, B, and C in the schematic diagram in Fig. 1. A radio wave flowing in the A or primary circuit, produces by induction a similar wave in the secondary or B circuit which, tube 1. If the primary winding of a radio frequency transformer, RT;, is placed in the plate circuit of the first tube, and the secondary of the transformer is placed in the grid circuit of the next tube, as shown in Fig. 8, the current flowing in circuit C will be reproduced in the grid circuit B, of tube 2. This current in turn will be ampli- fied by tube 2 and will result in a stronger current in plate circuit C;, with character- istics similar to the original cur- rent in the A circuit. By adding extra circuits and tubes the current can be strengthened. The current in the last plate circuit then can be rectified and way as radio frequency amplification. The main difference is that since we are dealing with low frequency currents, the trans- formers used vary greatly from those used in radio frequency circuits. In audio frequency amplification the various stages in amplifying the original current proceed in the same way as in radio frequency amplification, with the exception that the F terminals of the secondaries of the transformers connect directly with the minus lead of the A battery instead of being con- nected indirectly with the A battery leads through the B BATTERY ‘B’ BATTERY through the amplifying action of the tube produces a similar wave of greater propor- tions in the C or plate circuit. Whether the wave is amplified by the tube “as is’”—that is, as an electromag- netic wave of high frequency and of an alternating character, or one of low fre- quency, flowing in one direction—depends on the adjustment of the movable arm of: the potentiometer. This controls the char- acteristics of the grid current and the rec- tifying action of the tube, which serves as a detector. In all the photo diagrams illustrating this article the tuning unit consists of honeycomb coils. Any form of tuning coils, ' can be used instead, however. It is advis- able to use variable condensers across the coils, as shown in the schematic diagrams, in order to provide close tuning. These con- densers are omitted in the photodiagrams in order to avoid confusion. In the straight radio frequency circuit shown in Fig. 3 on page 64, a radio fre- quency current flowing in the A circuit is reproduced in the same form, by induction, in circuit B. By proper adjustment of the potentiometer this current is reproduced in the same form but in greater strength in eircuit C through the amplifying action of plicated circuits. reduced to audio frequency in either a crys- tal detector circuit, as shown in the diagram, or in a vacuum tube detector circuit. Now audio frequency amplification, or the strengthening of audio frequency cur- rents, is accomplished in much the same Explanation of Abbreviations Li—primary coil, 35 to 60 turns. L2—secondary coil, 40 to 60 turns. AT, —first stage audio frequency trans- former. AT2—second stage audio frequency transformer. RT; —first stage radio frequency trans- former. RT2—second stage radio frequency transformer. R—rheostat, 30 ohms for new dry cell tube, 6 ohms for old 6-volt tubes and 11% volt dry cell tubes. P —potentiometer, 200 or 400 ohms. A Battery —three 114-volt cells for new tubes. B Battery —22)4 to 90 volts. C2—.001 or .002 mfd. condensers. CD—crystal detector. Ant.—antenna. Gd.—zground. Transforming Standard Circuit into a Reflex Set At the left is the funda- “y '2 mental vacuum tube circuit, shown in photo and schematic diagrams. On this circuit are based all the supposedly com- Above is the hook-up for the single tube reflex circuit. Note the close relation between this circuit and the standard tube "GD hook-up, Fig. 1. The standard circuit is transformed into the single tube reflex circuit simply by adding an audio frequency transformer, a crystal cetector and a radio frequency transformer, in the positions shown potentiometer, as is the case in the radio . frequency stages. In the straight vacuum tube circuit shown in Fig. 1, the potentiometer is ad- justed to the point where rectification or detection takes place. Instead of this, however, an amplified radio frequency cur- rent can be made to flow in the plate circuit by proper adjustment of the potentiometer. This is what is done in the reflex circuit shown in Fig. 2. Disregarding the trans- former winding shown in the grid circuit of this diagram, we shall trace what happens to an incoming wave. The current flowing in the A circuit is reproduced in the B circuit and by proper adjustment of the potentiometer is ampli- fied by: the tube and produces a radio fre- quency current in the plate circuit. The primary of a radio frequency transformer is inserted in the plate circuit and the phones and B battery are shunted by a condenser to bypass the radio frequency - currents around the phone windings. By connecting a crystal detector in series with the secondary winding of the radio fre- quency transformer, RT,,.and the primary winding of the audio frequency transformer, AT;,, a rectified low frequency current can be made to flow in the detector circuit.

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beri Se rr aN A ee an stannic te nce ih RRA N A ST

aoe at _ wnt aghove agg interfere Fig. 4 2 then is introduced into the with eacn other. yok BL UP 6 P id circuit B of tube 1, am- _The same method of tap- “A : F Eg 5 cD Dlified by tube 1 and made ~ pies 3° from oe a cult — scam % bow Aly i to actuate the phones placed Cacao Rage i: in the plate ‘reuit Co ’ ae . tube 1. as in the single tube reflex cir- , 4 Th ae : : 2 Cc. | e same principle a cult, noel - erg ith a GD. R , : "RT, plies when more than two larger number of tubes. @ R stages are used. In such In the two yi reflex cir- - cases the output of the plate cuit shown in Fig. 4, the cur- ¢ ile Mig rent flowing in the primary - circuit of any tube is — circuit is amplified through two radio frequency amplify- ing stages and passed into the J detector circuit D. The 2 audio frequency rectified cur- rent then is introduced into the grid circuit B, amplified by the tube, and tapped off from the plate circuit C and introduced into the grid cir- cuit Bj of tube 2 by the transformer AT». It is then amplified by tube 2, resulting in agreatly strengthened audio ANT. Popular Science Monthly

windings, so that the circuit between points 1 and2 might just as well be open. The use of these bypass con- densers, shown in the dia- grams as Co, is very’ im- portant. The inverse duplex cir- cuit merely is a modified

C2

Radio Frequency Circuit In this straight radio fre- quency amplification cir- cuit, two tubes are used as radio frequency amplifiers, while a crystal is used for detection. Note again how this circuit is based on the standard tube circuit shown Straight Reflex Circuit —Here two tubes act as both radio and audio frequency amplifiers. After the radio frequency current has been rectified by the crystal detector, it is fed back into tubes 1 and 2 to be amplifiea at audio frequency

and if you understand the reflex circuit, it should present few difficulties. In the inverse duplex, the out- put of the detector, instead of being introduced into the grid circuit of the first tube and being amplified pro- gressively in the same order as the radio frequency cur- rents, goes through the amplifying stages in the reverse order. The output of the detector circuit as shown in Fig. 5 is introduced into the grid circuit B, of

BATT

form of the reflex circuit, °

This the c ordin sists dome

frequency current in plate circuit C;. This By), a fixed condenser Cz of .001 or .002 duced into the grid circuit of the preceding fin current then will actuate the diaphragms mfd. capacity is used to bypass the radio tube instead of into the grid circuit of the a of the phones placed in this circuit. frequency currents flowing in the circuit, succeeding tube, as is the case with the - _ It will be noted that wherever the wind- thereby preventing them from going _ straight reflex. In the straight reflex circuit ings of the audio frequency transformers through the high resistance windings of the __ the first. tube of the series handles a weak are introduced into circuits in which radio audio frequency transformers. The low or radio frequency current and a weak audio Fe frequency currents are present (such as audio frequency currents, however, find an frequency current, while the last tube ey between points 1 and 2 in the grid circuit easier pathway through the transformer handles a strong radio frequency and a be Fig, 5 I Duplex Circui strong audio fre- lo nverse Duplex Circuit quency current. This ~ - Here the operation is the arrangement, therefore, e} oie ty bl, sl fp a same as that of the reflex cir- has a tendency to un- th BATTERY TUBE AT, TUBE | ee’ cuit, except that the rectified derload the first tube le A 1 1 2 current is amplified first by 2 and overload the last tl ay F RI, tube 2, then by tube 1, in- tube. In the inverse i ANT. G np 'o G RY stead of the opposite order. P - ait : ; ‘ Also, the telephones are duplex a better balance bt es 2 PG Co % placed in the plate circuit of is obtained, since the i R RT, tube 1 instead of tube 2 first tube will handle a R wealt radio frequency ¢ P. ANT aes | current and a strong i WS dlaale -_aleuah audio frequency cur- % ft Ep Rig Frrmmmg URE om 5~A, CD rent, while the last tube . bh] @ c Q ee: will handle a strong ( B CG D radio frequency cur- B . ZR re rent and a weak audio «a a Rl, frequency current. ‘BATT. ; a a 2 Next th Jack ex mon ac GD. G Binns_ will | explain es Ly the design of timed ort ail radio frequency and ; | neutrodyne circuits. 66 Popular Science Monthly Pomme ere ae hl ORM nme

a a So eT Soe i min. tae Ls. xt. 2

Ty

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‘ircuit might Bi of lified nt in tube o the ,am- made — laced ding the the cuit eak idio ube da re- ‘his ore, un- ube last nce the lea ney ong ur- ube ong ur- dio ack ain 1ed nd its. This fork attachment ‘“‘takes the cake.’”’ Slipped over an ordinary table knife, it as- sists in the well known domestic juggling feat of serving layer cake Knife and scissors grind- ing at home is made easy by the machine shown above. All that is neces- sary is to place the blade between the two rollers and turn the crank. Even fine silver table knives can be sharpened in this manner without injury For persons with poor eyesight, the ingenious needle threader shown below holds a fine wire loop that may be in- serted easily through the eye of a needle. The thread is placed in the loop and quickly drawn through the needle’s eye Popular Science Monthly 65 New Inventions for Household Convenience A Page of Useful Ideas for Greater Comfort in the Home Either a long or a short handle can be inserted in the block of this floor mop. The block serves also as a handle A toothpaste cabinet fastened to the wall is the latest in bathroom con- veniences. The tube is inserted in the cabinet. A durable tape connected with an outside hand key rolls up the tube as key is turned, ejecting paste Popular Science Monthly WT, *T7T 4 A safety device for handling hot baking tins consists of narrow strips of metal attached to the sides and ends, into which fits a metal bar with wooden handle A large family wash may be hung in a small kitchen by use of the triple hanger shown above. Thirty-six arms that may be folded or extended provide 40 feet of hanging space SSRN AR lps] 195 9 in wringing the mop (_——— This new oven thermom- eter measures heat just as a clock measures timie. The temperatures of either gas, coal or elec- tric ovens are read on a dial. Accompanying the thermometer is a chart showing the correct heat required for baking vari- ous articles of food The onion mincer shown below is designed to save the housewife tears. The onion is dropped into a covered glass jar, where it rests on a_e small wooden chopping block. Four cutting blades operated by a spring plunger do the mincing

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isis aha ee rae eT a ee amen eraser ew: sae 2A: MORTAR TF Sac SAL kas aaa Beauty Made to Order by Machine] R

MEDUSA? Curls that stay curled are produced by this electrical permanent waver — an entirely mew beauty device. First the hair is wound on curling rods, moist- ened with a permanent wave lotion, then wound with flannel, until little pipe stems stick out all over the head. These are in- serted in hermetically sealed heating tubes, suspended from a chandelier as shown above. After steaming for seven minutes, the hair is unwound and shampooed. And there are the coveted curls CURLS FOR A WEEK At the right is the latest machine for drying delicately the water waves that make the hair a sea of curling bil- These waves are formed by moisten- ing the hair with water lows for a week. Popular Science Monthly

GE LLL My Le Lia

Vudu DOOMED

\

A COAT OF SUNBURN WHILE YOU WAIT From Paris comes this new appliance. Powerful re- flectors bathe the skin and hair with ultra violet rays, said to produce a glorious vacation tan in a few minutes. It is claimed the rays also nourish the hair

DUNCE CAP? NO! It’s a beauty cap— the newest invention for drying the scalp and skin after the hair has been waved. An electric heater and blower circulate warm air through the pipe and into the cap, where it thoroughly dries the scalp of the beauty “patien’ 9

NA | hol pie ratus— toaster sort—t it appe or it bl it is ce If y< ance, | Try to Heat ably a electri: pair, fe fine V wiring produc curren wire | This | held it two s quence: Bef wheth that t] cord 0 to fai wires cords quent kinke ing a articl mont! cord cable, likely heate Wh Aft cord and 1 dism: faces ery. sprin likels temp place new and that will They a fev certs agai inst: shou orde orig’ T swit shov top | sock sock the pow

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Popular Science Monthly le] Repair It Yourself Simple Ways to Mend Worn Electrical Heating Appliances at Home ? NO! cap— vention e scalp the hair d. An rr and © warm he pipe p, where iries the | beauty — - Pra ae eee eee De os ibe i Se ERS Be ee nad Spe SB; - By Victor H. Todd Member American Institute of Electrical Engineers hold there is at least one piece of electrical appa- ratus—usually a flatiron, a toaster, or a heater of some sort—that won’t work. Either it appears to be “‘burnt out” or it blows a fuse every time it is connected. If you have such an appli- ance, don’t throw it away. Try to fix it yourself. Heating appliances prob- ably are the easiest sort of electrical’ apparatus .to re- pair, for they contain neither fine wires nor complicated wiring systems. The heat is produced by passing. electric current through a winding of . * wire or a resistance strip. ——_ This heating unit usually is held in place by only one or two screws and in conse- quence may be removed easily and replaced. Before deciding that the heating element, whether coil or strip, is burnt out, be sure that the trouble is not caused by a defective cord or plug. Flatirons especially are likely to fail to work from this cause, for the wires inside the insulation of the flexible cords connecting them with the sockets fre- quently are broken by being carelessly kinked and twisted. The methods of find- ing a defect in a cord were described in my article on fixing household motors last month. Be sure, though; in replacing your cord that you use an asbestos insulated cable, since cords insulated with rubber are likely to cause an offensive odor when heated, and to develop short circuits. When to Replace Switch and Plug After you have satisfied yourself that the cord is not defective, look next to the plug and the cut-out switch. These should be dismantled and the contact sur- faces carefully cleaned witli em- ery. If the blades or the contact springs are badly discolored, it is likely that heat has destroyed the temper. If so, it is better to re- place the switch or plug with a new one. Any attempt to clean and rebend blades and springs that have been sdftened by heat will result only in a makeshift. They may make good contact for a few weeks; then they are almost certain to produce an open circuit again. If a new plug or switch is installed, the contact surfaces should be cleaned with emery in order to avoid a recurrence of the original trouble. To test the cord, plug, and switch, rig up .the apparatus shown in the illustration at the top of this page. It consists of two sockets—a test socket and a lamp socket—connected in series from the wall plug. Insert ‘a: large power lamp in one socket to pre- ik ALMOST every house- Dismantling an electric iron.. After two bolts in the handle are removed, the heating element can be inspected readily vent blowing of the fuse. In the test socket insert the plug of the heating appliance lead. If any short circuit exists either in the plugs or the wires, the lamp will light. If it does not light, wiggle and twist the wires where they are connected with the plugs. If the lamp flickers now, it denotes an imperfect connection that will develop heat and trouble when the heating appli- ance is in use. If, after defects in cord and plug have . been remedied, the appliance still fails to heat, it probably is burnt out. To deter- mine whether this is so, place a small test lamp in the lamp socket, and to the test socket attach two leads terminating in tape- wound nails. Now touch these leads to the terminals of the heating appliance. If the test lamp lights, the heating circuit is in good condition. If it fails to light, the next step is to open up the appliance and locate the trouble. If it is an electric iron that is being ex- ” “~~ peas Cnr aemaamn Failure of the electric percolator may be due to the melting of a protective fuse or the opening of a thermo- Static switch in the false bottom of the appliance wea TEST CIRCUIT 23> PLUG | ma) RESISTANCE LAMP SAFEGUARDS FUSES | | TEST SOCKET. LAMP SOCKET Wa” ~a ee wo sci —- TEST LEADS aks (TAPE WOUND NAILS FOR TESTING CIRCUITS) This simply constructed ap- paratus for testing heating appliances consists of two sockets connected in series from a wall plug. In the socket at the right is inserted an electric lamp. The appli- ance to be tested is connected with the socket at the left. With each terminal of the test socket is connected a test lead ending in a tape-wound nail. These leads are used to connect terminals of the heat- ing appliance into the circuit amined, this step should be comparatively simple. First remove the bolts in the handle of the iron that hold the top and bottom of the appliance together. The heating element usually is wound with a flat strip of resistance metal on 2 mica card, placed above the base of the iron, Iron May Need New Element Before proceeding further, carefully ex- amine the connection between the strip and the terminals. If this connection is open, it may be reconnected; but if the open circuit is caused by a break in the actual winding, do not attempt to weld or braze the joint; it will only make a bump and cause the strip to burn out. A new element may be bought at a reasonable price and reinserted, making the iron as good as new. If pos- sible, obtain the heating element recom- mended by the manufacturer of the iron. This may be put in place with a sheet of mica above and below the heater and the iron tightly bolted. Then trim off any rough mica edges that project. Upon replacing, test the iron for “grounds.” To do this, con- nect one side of the test line with the plug and the other test line with the base of the iron. Use a large lamp in this test, connecting the repaired iron at the test socket. This will cause the iron to become warm if the lamp lights, indicating a short circuit. This must be found and corrected before the iron is put to actual use. If your coffee percolator is out of order, it may be because you carelessly permitted the current to remain on after the coffee had boiled away. To prevent the heating element from burning out when this occurs, a fusible strip or a quick-break thermostat is placed in the bottom of the tank (usually under a false bottom). When the apparatus is overheated, this strip melts or the automatic switch opens up. If the “open’’ is due to either of these causes, you need

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ey ram peng 68 merely obtain a new strip and solder it in place, or clean and reclose the thermostatic switch by hand. In percolators, the heater, if burned out, may be easily removed and replaced. Never try to solder the resistance wires if broken, as the operating tempera- ture will only melt the solder. Heating pads should be handled with care as their heating elements consist of very fine wire wound on asbestos rope. With proper care a pad will last many years with one or two cord renewals, but with severe use, it may not last a month. “Opens” in these pads may be found by unwinding the outside wrapping of asbestos until the break is exposed. This wire may be cleaned, twisted together, soldered, and retaped. But don’t be too eager to rip apart and unwind when the pad does not heat, for the trouble may lie in the automatic switch or ther- mostat in the pad. Remove the outside covering and expose the thermostats (there are usually two). Try them with the test lamp. If an open circuit is found, look for broken leads, and open the ther- mostat if necessary, carefully clean- ing the contacts inside with a fine Popular Science Monthly file or emery cloth. Replace and try again. Carefully anchor the cord by using plenty of strong thread or twine, weaving it in and out through the resistance ropes. In apparatus with heaters exposed to the air, such as In repairing any electrical heating appliance, such as the waffle iron shown above, you will find usually that the removal of a screw or two will permit the entire heating element to slip out easily toaster stoves and luminous heaters, the heating element is easily burnt out. Know. ing this, manufacturers design the appa. ratus so that a new element may be inserted readily. The removal of a few screws wil] permit the damaged element to be taken out and a new one inserted. So don’t let your inoperative elec. trical apparatus lie on the shelf gathering dust. So many men who have no working knowledge of elec. tricity, allow its ‘‘mysteries” to scare them. And yet, taken step by step, such repairing as described in this article is very simple. A little thought and a little labor soon will have apparatus working as well ag ever before. The hints I have given in this and the preceding article should be sufficient to enable any one to re- pair any of the electric utensils to be found in his house. Possibly, though, I should utter a warning— if your electrical appliances are working satisfactorily, let them alone! Don’t tinker with them unless they are actually out of order. This is the second and conclud- ing article of Mr. Todd’s series. Carloads Weighed while in Motion pact pedenavagpe using large quantities of coal, stone, and similar materials always have lost much time through the necessity of halting the materials in transit to weigh them. Now there has been devised .a scale by means of which any sort of material, whether carried by car, bucket, or on belts, may be weighed in motion. In addition, the scale automatically supplies records both of the weights of individual units and of the total amount of material carried. This is accomy lished by an ingenious sys- tem of suspension and gearing. A portion of the conveyor is suspended in a way that may be compared with the ordinary plat- form scale. From this extends the weighing beam, counterbalanced by a steel float in a mercury bath. This float permits the beam to move from its zero position as the weight of the materials falls on the suspended por- tion of the conveyor. The conveyor is geared to the weight in- dicator so as to transmit to it the beam motion in proportion to the speed of travel. The result is that the two factors of speed and load produce an accurate indicator reading. GEAR MECHANISM OPERATES SCALE } Platform of scale that weighs suspended like an ordinaty beam scale. 70 material in motion, showing how portion of track is SUSPENDED PLATFORM es Inset shows beam and weight indicator Popular Science Monthly Traits of Character Read by Lever Machine pl you be depended on in an emer- gency? Will you persevere in a difficult task until you have completed it, or will you quit? Professor Thomas D. Howard, psycholo- gist at Northwestern University, claims that science now can tell these things about you, and can define unerringly other of your characteristics by means of a char- acter-reading machine he has invented. Traits of character, he asserts, are re- vealed by the manner in which the person being studied operates a set of signals con- trolled by hand levers and foot pedals on the machine, in response to dictation of. orders from the examiner. Self-reliant, alert persons will pull the right levers and push the correct pedals un- hesitatingly the instant they are informed what signals are desired. Persons of weak | and flabby character will fumble around and make mistakes. Egotistical persons will blame their errors on the machine. Per- sons who lack perseverance will seek to abandon the machine after a few mistakes. Other differences in personality and char- -acter are .revealed with equal plainness. .

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aters, the it. Know. the appa. e Inserted crews wil] be taken d. ative elec. the shelf men who ge of elec. erles” tg on step by scribed in A little soon will aS Well ag n in this should be me to re- tensils to Possibly, yarning— neces are let them th them r out of conclud. series, nh emer- ult task vill you sycholo- claims 's about ther of a char- ted. are re- person als con- dals on tion of. ull the als un- formed f weak | around ersons e. Per- eek to stakes. d char- inness. . Popular Science Monthly 69 World’s Only Bed of Epsom Salts Won by Engineering Skill By Philip Johnston HROUGH modern T engineering _ skill the world soon will be able to avail itself of one of its most re- markable chemical de- posits—a vast bed of magnesium sulphate, the chemical compound known commercially as Epsom salts. This deposit—the only one in the world that contains magnesium sul- phate in a pure state—is logated amid the arid wastes of Wingate Pass, near the west side of Death Valley, California For years after its discov- Nature’s snow-white treasure. balancing device unnec- essary. Sway and vibra- tion are eliminated by guide rollers running on horizontal planks on each side of the trestle and three feet below the rail. The cars are designed to carry five tons each, and it is expected that trains of 20 cars will attain a speed of 12 miles an hour when the road is electrified. At present, the monorail is being used only for construc- tion purposes, power be- ing supplied by a special tractor capable of haul- ing two five-ton cars up a 10 per cent grade. Here are lumps of pure Epsom salts In its course from the ery it lay untouched, sim- found under three inches of soil in deposits near Death Valley, Calif. mine to the railroad at ply because of its inacces- sibility to any form of commercial transpor- tation that could be devised. To-day the resourcefulness of engineers at last has suc- ceeded in bringing the desert treasure across rugged mountain ranges and through rocky passes to refineries where it is made avail- able for everyday use. - _.T. H. Wright, of Los Angeles, uncov- ered the deposit while prospecting in the walley: many years ago. He realized its ‘value, and scientists who examined it confirmed his estimate. But they were helpless to-move it. The nearest railroad ‘was more than 70 miles away. Building :a connecting railroad line over the moun- tain ranges which intervened manifestly was impossible. Use even of the hardy mule teams which hauled borax from other parts of the valley was impracti- cable here, for the roads and trails ‘scarcely could be negotiated by a pack animal. Monorail Line Offers Solution The development of the motor truck offered no solution of the difficulty, for, even if it were possible to build automo- bile roads, the trucks themselves would be unable to withstand the wear and tear of frequent trips to and from the valley. Yet in spite of all obstacles, Wright continued to work on his problem. Re- cently he perfected a revolutionary type of monorail that promises the only prac- tical solution. Construction of his road has progressed to a point which-seems to indicate that Epsom salts from the Wingate Pass deposit will be placed on the market within a few months. The single rail of Wright’s railroad is hung on a trestle. The cars are suspended from the rail, making any gyroscopic Monorail cars hauled by a special tractor used in construction work .on the monorail line into the Wingate Pass Epsom salt deposits of California.’ The upper photograph Popular Science Monthly shows part of the remarkable railway winding in and out among rugged mountains Trona the monorail cars frequently will be required to climb 10 per cent grades and round 40 degree curves— feats that would be impossible with any. type of standard or narrow gage railroad. No earthwork is necessary in construction, for the height of the trestle can be varied according to the contour of the ground. The cost of construction is said to be much less than that of a truck road. The world gets its supply of Epsom salts at present from Germany and the United States. The German product is mined from great depths, and requires three separate processes of crystallization to remove chemical impurities. Filtering then is necessary, to take out particles of earth that are mixed with the solution. Methods of Preparation Simplified The preparation of the usual American product is even more difficult. _Magne- site, or magnesium carbonate, a hard rock found in various parts of the coun- try, is first crushed, then treated with sulphuric acid. Magnesium sulphate is formed in the process, but in an impure filtration, crystallization and evaporation to be purified. Preparation of the salts found in Win- gate Pass is extremely-simple as com- pared with methods used elsewhere. The salts are dissolved in water, all dirt and silt settling to the bottom. Then the tem- perature of the liquid is lowered slightly, causing a small percentage of sodium sulphate to crystallize out, leaving a mother liquid of magnesium sulphate. After filtration, this is 99.8 per cent pure. After the water has been evaporated, the salts are ready for the market. It is esti- mated that Epsom salts can be refined in this manner for about one fifth the cost of obtaining them from magnesite. The visitor to the deposit observes only a bit of desert landscape, interspersed with small hills that appear to be composed of clay. But the soil on these hills is only two or three inches deep, and under it lies a hard crust of pure magnesium sulphate, white as snow. The deposit covers 1400 acres. That it has remained intact is due to the ab- sence of rain, which would have washed the salts away. state, requiring several operations of Se eee god eae SS Heng eo ny hate ee ee BE ee en eae SRT I

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i RE ; if 4 it g a Popular Science Monthly 500, 000 Miles in World’s Best Equipped Auto \ N J ANDERER III, official scout car of the American Automobile Asso- ciation and accredited represen- tative of the government National Parks Service, is said to be the best equipped and most dependable car in the world. This remarkable automobile, fitted with every conceivable appliance and accessory for efficiency and service, has made 16 trips from the Atlantic to the Pacific, and has covered 500,000 milés of highway in the United States during the last seven years. It works as a pathfinder, inspecting auto- mobile routes, finding new trails and lo- cating impassable roads. An endless tread attachment, running on rollers located beneath the runningboards, enables the car to traverse the roughest country. Other equipment includes: Powerful jacks, capable of raising the car, which weighs 7400 pounds, five feet from the ground. Unusually powerful headlights that il- luminate the road for 1500 yards. Special compressed air shock absorbers. A compass, grade meter, altitude meter, mapmaking instruments and special ther- mometers that record temperatures inside and outside the machine. A battery recorder that indicates the charge and the amount of water in the battery. An apparatus that makes a complete road log of every trip the car completes. New Automatic Gear Shift Controlled wondered why somebody didn’t in- vent an automatic gear shift that would operate mechanically without elec- tricity or some other out- | ee years automobile drivers have The Wanderer III. Note the elaborate dashboard equipment at the right Treated with radium, all the registering and recording instruments can be seen al- most as clearly at night as in the daytime. One of the most striking features of the Wanderer III is a new electrical lubricating system. Simply by pressing an electric button the driver can oil the entire chassis while the car is in motion. well as the neutral position. When the lever is set for any position, a number of arms operate to move a preselector mechanism into the proper position for that speed. side power agency—a gear shift suitable for any car and one cheap enough in price for the average pocketbook. At last a group of Mich- igan automobile men claim to have perfected just such a device and have incor- porated to manufacture it. While automatic gear shifts have been in opera- tion on several makes of cars for some time, they At the left is shown the arrangement of the steering wheel shift lever that replaces the usual long arm lever above the transmission have depended for opera- tion chiefly upon electric- ity. The new apparatus is mechanical and its action is positive, although the personal element so necessary for the proper control of the car is not eliminated. The driver still can feel the movement of the gears and can control the accelerator accordingly. The usual action of the clutch and the arrangement of gears have not been altered in the new invention. The usual long arm shift lever has been eliminated, and a small lever arm at the center of the steering wheel takes its place. There are several advantages in this arrangement. One of these is the fact that it leaves more room in the front seat and it becomes easier for a driver to get into the seat from either side. Another advantage is that it is not neces- sary for the driver to release the wheel when shifting gears. He can shift the speed con- trol arm as readily as he moves the throttle. This lessens the possibility of losing control of the car. On the shift lever sector there are a number of letters indicating the positions of first, second, third and reverse speeds, as 72 a CLUTCH “4 ROLLER SS Automatic gear shift assembly. When steering wheel shift lever is moved, it operates a preselector mechan- ism, setting arm W in position for desired speed. Then, when clutch pedal is depressed, the clutch roller passes over a cam, operating arms so that arm-O moves the gear forks in transmission box into proper Note plan of hand and pedal brakes engagement. Popular Science Monthly INSTRUMENT BOARD HAND BRAKE at Steering Wheel When the clutch is depressed, a cam is moved.to operate-a second set of arms which causes the previously set shifting arm to engage the gear yokes and move them into the proper position. Upon the release of the clutch pedal the engine again is hooked up with the transmission system and the car is driven through the set of gears selected with the shift lever. Since the shifting cannot be accom- plished before the clutch has been disen- gaged there is no danger of stripping the gears. At present there are many drivers who ruin the gears by trying to shift when the pedal is not completely down. This is obviated in the automatic gear shift because the design of the shifting cam is such that the the pedal is fully depressed. Because of this feature, it is possible to change the prese- lector from high to second speed while going up a hill and having the shifting mechanism in immediate readiness for a change. This eliminates the possibility of stalling the car while changing gears, a fre- quent occurrence with the present methods. At present it is necessary to remove all power from an auto- mobile during the period in which the shift lever is moved. With the new arrangement, it is necessary only to throw out the clutch and let it back again. The car will not have slowed up appreciably during that shorz interval. In starting the car the lever is placed in first position. Mov- ing forward through the neutral position it is then placed in sec- ond speed, and finally in third. device will operate only when’ He

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cam is f arms ng arm > them release rain is system set of iccom- disen- ng the lrivers - when This is c gear of the at the when: sed. , it is prese- econd ll and anism for a s the e car . fre- the ry to auto- d in oved. nt, it y out gain. d up shors lever A ov- utral sec- hird. Popular Science Monthly 71 How to Get Your Money’s Worth % Ry REAR AXLE running gear for any flaws, as indicated above. ' By Harold F. Blanchard © Noted Automobile Expert F YOU are about to buy your first ] automobile, you probably are con- fronted with at least four perplexing questions. How much should you pay for acar? What make is best for you? Should you buy a new or a used car? Should it be a closed or an open model? Scores of prospective purchasers have asked me these questions. The last three are somewhat difficult to answer; first, be- cause there is not much to choose between various makes of cars at any particular price in ‘this day of standardization. Then the question of whether the car shall be a new or a used one can be decided only after careful consideration of the values offered. And, finally, the question of an open or a closed model depends largely upon indi- vidual tastes and needs. But the first item can be answered with scientific exactness. The price When You Buy a Car INSTRUMENT BOARD CRANK-CASE == In buying a car, especially a used one, have a mechanic help you inspect the vital parts of engine and ' Then drive the car yourself to test its performance a $2500 car; if $15,000, a $8750 car. By purchasing a car which lists at 25 per cent of your income for one year, you bring the total expense of upkeep well within your means. If you are edrning $2000, the yearly cost of running a car, assuming you give it the average care, will be $276.60 or 13.38 per cent of your income; if you re- ceive $5000 annually, and buy a car accord- ing to your means, your total running ex- pense will amount to $473.20; while if your business pays you $20,000, the total car upkeep cost will figure $1488 or 7.44 per cent of your income. : On a mileage basis the cost of running your car, all expenses considered, will vary, according to the initial cost, between 4.46 cents and 24.80 cents, as tabulated on page 72. The figures in this table are designed to represent an average case in each particular class. The initial cost of the car includes war tax, freight, and all extras. Also it is assumed that the car is driven 30,000 miles over a period of five years, and that at the end of that period it has a value of from $100 to $600, depending on its original price. The cost of gasoline is figured at 25 cents a gallon, while the mileage a gallon varies from 22 miles for the $500 car to 10 miles for the $5000 car. Some cars may exceed these figures; others may fail to reach them. But it may be assumed that they strike a fair average. There always will be some question about oil consumption. Some owners obtain 300 miles or more per quart and others get less than 50 miles; it depends on the condition of the engine and the construction of the lubricating system. Averaging up these factors it has been found that 100 miles per quart of oil for cars valued at less than $2000, and 150 miles for cars above $2000 is a fairly accurate estimate. Oil and gas are the first things the aver- age motorist thinks of in computing his operating costs, but there are that should be paid has been other expenses that must not be figured out closely by economists and statisticians. They agree that you can afford a $500 car on an income of $2000, and that it is not advisable to purchase a $5000 car unless your income is $20,000 or more. A careful analysis of these figures shows that you can afford to spend a sum equal to 25 per cent of your annual income —not every year—but one yearin | five. Thus, if you receive $5000, you can afford to buy a $1250 car; if $8000, a $2000 car; if $10,000, ID you know that failure to keep the steering knuckle of your car properly oiled may result in fatal accident? In an important article next month will be re- vealed scientific secrets of automobile lu- brication, learned by experts through long experience—facts that not only will help you to cut down car costs, but may save _ you from possible injury or. even death. You can’t afford to miss this article. overlooked. Tire cost is an im- portant one. Since cord tires now are used largely, the average car may be expected to run approx- imately 12,000 miles on a set. Consequently tires must be pur- chased at about the 12,000 mile mark and again at 24,000 miles. This means at least eight tires with tubes and flaps, in the five year period—tires costing from $22 to $48, according to the class of car. Then there are the items of Popular Science Monthlv 79

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72 painting, upholstery, top repairs and re- placements. The insurance figures also represent average requirements. If you own a $500 car you are likely to be satisfied with fire and theft protection. But the greater your possessions, the more you are likely to feel the need of safeguarding yourself against damage suits. And that explains why the figures under this head vary from $20 yearly to $200 yearly. Total repair figures range from $172 to $410 and include valve grinding and carbon removal every 5000 miles, bearing and other adjustments, one set of new piston rings, brake lining, Popular Science Monthly up”. basis and never on.an.‘“‘as is” basis. Don’t be fooled on the tires. If you figure you will have to buy a complete new set of tires within 2000 miles, probably you will not be far wrong. Then be sure there are no big defects such as cracks in cylinders, crankcase, or rear axle housing. Get a re- pairman to determine these points if you cannot trust your own eyes. If possible, remove the cover plate from transmission and rear axle and inspect the condition of these parts. Examine the car to determine whether it has been in a collision or a fire. Evidences of straightened members will in- America. It is considered by many the ideal all weather model, as satisfactory jp summer as an open car ‘and much more go in winter. They point out that “the top jg always up” and there are no side curtains to bother with in case of sudden storm. One reason why more motorists do not have closed cars is because of the additional initial expense. Fortunately, within the past year and a half, great strides haye been made in the economical construction of closed bodies, with the result that there are several closed cars selling for within $100 of the corresponding open models, Thus the greatest drawback battery repairs and replace- ments. Now in purchasing a new car on a scientifically econ- omic basis, the fact to be kept constantly in mind is that your yearly expense figure should not greatly exceed that listed in the table. If your income is $2000 you After deciding how much you are to pay for your car, your next problem probably will be to decide whether to scientific cost averages compil What You Can Afford to Pay for a Car N THE first column of the table below, pick out the figure representing your yearly income. will read what you reasonably can afford to pay for a car and what it should cost you for upkeep annually. This table is based on by expert economists and statis- ticians, and assumes that the purchased car is driven 30,000 miles over a period of five years. What It Should Cost You to Run a Car | The table above is based on the following cost figures over a five-year period. Opposite this figure you to owning a closed car is being eliminated. But the increas. ing popularity of the closed car does not mean the passing of open models. These will always have their supporters, Having determined the price you can pay for a car and whether it will be an open or a closed model, the selection of the particular ifications should range in im- portance according to your personal preference. j may spend $276.60 yearly for Total Percentage Total — make remains. all items of expense. Depre- ee. — Seowie A Roache r Mile The standard cars built ciation on a $500 car over a Upkeep Car Upkeep (in n Cents) to-day, even more than those period of five years is $400, $2000 $500 $276.60 13.38 04.46 built two years ago, generally : that is, $100 is the estimated 3500 875 368.60 9.83 06.14 are satisfactory, so that the : efficiency value at the end of 5000 1250 473.20 9.46 07.89 selection of a machine in i this period, provided the car 8000 2000 662.40 8.27 11.04 any given price class may be ; has been carefully used. 10,000 2500 790.10 7.90 13.19 determined by considering : Adsice to B 15,000 3750 903.80 6.03 18.40 omen cones ae ae t a 20,000 5000 - 1488.00 7.44 24.80 re t Trying Out a Car If you live among steep hills, you are likely to want a good hill climber, or if you live on the plains you may prefer a car with ability to slide along easily at high speed. Take your demon- stration on the roads on which you expect to travel. buy a new or used one. If you aj Value _.,,0il Gasoline Cost o . Li- ved absolutely nothing Gost of 30,000 ‘oars Baionde Miiends One Ti ire woo eo about automobiles, you do ar Miles Yearly Gajion Gallon Tube Once ly well to buy a new machine. $500 $100 $20 100 22 $22 $50 $172 $5 Then follow the instruction 875 125 30 100 20 26 60 190 7 book implicitly in taking care 1250 150 40 100 18 30 70 205 12 of it.: By this procedure you. j/ 2900. 300 75-150 16° 30 80 245 15 are likely to operate with the 2500. 400 100 150 14 40 100 270 16 minimum expense per mile. To a lesser extent the same 3750 500 150 150 12 40 125 325 17 holds true of cars a year old, 5000 600 200 150 10 48 150 410 20 and of some cars two years The springs of the car that you favor may work very old. But as a general rule, used cars more than a year old should not be purchased by inexperienced motorists, be- cause such cars are likely to develop many little troubles. These may not bother the man who is “motor wise,”’ but they are sure to cause much trouble and expense to the novice. Then, too, used cars three, four, five or more years old are not always bargains. A cheap car more than five years old is likely to cost more to repair than it is worth. For example, a man I know recently bought a 1918 six for $100. He spent $300 trying to fix it up and eventually sold it for just $100. Another man paid $300 for a better car, spent $600 in repairing it, and now, after investing $900, he has a five-year-old “machine in fairly good condition. But think of the fine one-year-old cars $900 will _ buy, or the fine new cars, for that matter! ~ Figure Cost on “Fixed Up” Basis In deciding to purchase a used car, ask yourself “‘Is this car for $300 as good a buy as some other? . It will cost $200 to fix it _up. Now $200 plus $300 is $500. Isn’t there a newer car that.I would prefer for $500?” Probably there is. When determining whether an old car is a bargain, always figure its cost on a “fixed dicate the former, and charred wood in the body framework often will indicate the latter. If the body structure is sound, fire is not serious, but a collision jars the whole mechanism, throwing the car out of aline- ment. A car that has been in a collision and repaired, should be purchased only after the most searching examination of its details. Before you buy, you should drive the car you intend to purchase. Its performance should be carefully noted, and any defects run down to their source. The starter should be used long enough to determine that there are no broken teeth on the fly- wheel and all gears, including reverse, should be tried, as well as both brakes. The most common form of deception in selling used cars is to misrepresent the age. Then too, badly worn cylinders sometimes are concealed temnorarily by filling the engine with heavy steam cylinder oil, or even by packing the pistons with grease. The easiest way to determine the condition of the cylinders is to have the crankcase drained just before the demonstration and then filled with medium oil—at your ex- pense if necessary. A great many people are undecided whether to buy open or closed cars. The closed car is becoming the more popular in 74 Popular Science Monthly well on relatively smooth roads but very disappoint- ingly on rough roads. Also take your demonstration at your usual driving speeds, and with your usual quota of passengers. The riding of the car, as well as its ability to climb hills, is directly affected by the num- ber of passengers. Be especially careful that the driver’s compartment is comfortable for you. See that the brakes are powerful and easy acting; that the clutch pedal and gearshift lever suit you; that the accelerator pedal i is rightly placed; that the steering gear is correctly positioned and that the seat and back cushions are the right size and shape for your comfort. Buy from Reputable Dealer Finally, other things ‘being equal, you should buy your car from a dealer with a reputation for good service, because if you expect to sell your car after a year or so, the second hand value will be determined largely by the care and service it gets. Some cars have a used value much higher than the average. It depends on how the car has been used as well as on the popu- larity of the machine. The popularity of a machine in any given price class is an accurate gage of its worth, because popu- larity is based fundamentally on worth.

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many the factory jn h More go ‘the top ig curtains to rm. sts do not additional] vithin the "ides have nstruction that there or within n models, drawback ar is being 1e increas- the closed he passing These will upporters, ined the for a car ill be an 10del, the particular ars built han those generally that the achine in ss may be »nsidering and per- iree class- ige in im- | to your Car yng steep to want a or if you you may ability to at high * demon- roads on 0 travel. e car that ork very - smooth sappoint- ake your 1g speeds, assengers. ability to the num- > driver’s you. See and easy gearshift r pedal is g gear is seat and ind shape aler jual, you er with a ase if you or so, the stermined > it gets. ch higher | how the the popu- arity of a ass is an use popu- worth. Non-skid cleats of drop- forged steel, somewhat re- sembling the “spikes” of baseball shoes and locked over the tread of the tire by non-rusting chains, form the latest innovation in automobile tire chains. The special adjustable locking device is shown above Protection from over-inflat- ed tires is offered by this new control device for ser- vice stations. The dial gage is set at the desired pressure. When this is reached, the device automatically cuts off the air ._ Anew automobile lock fast- ened to the steering post con- sists of a steel fork that swings upward on a hinge to engage a spoke of the steering wheel Popular Science Monthly Aids to Car Safety and A special locker for the golf bag is just one of many con- veniences built into the body of this new sporting road- ster. These include a buffet concealed in one door, and an ice chest Attached to the windshield, this automobile compass is insulated from the magnetic influence of the metal and electrical apparatus of the car. Possibility of error is pre- vented further by an inner compensating mechanism Automatic control of the cooling system is provided by this thermostat, shown in cross section, which is clamped into the hose at the point indicated by the heavy arrow This novel air pump, clamped to the runningboard, is driven by the automobile engine through an arm attached to one of the rear wheels Popular Science Monthly 73 Comfort To prevent small boys from stealing rides by sitting on the rim of the spare tire, this spiked plate has been ~ devised. When bolted to the tire rack, it offers a seat about as inviting as a picket fence To permit the driver of a closed car to signal in stormy weather, this special window is made in two sections. The bottom section is hinged to open out- ward as the driver thrusts his arm out A new three-speed trans- mission attachment for Ford cars, resembling the transmission in large standard cars, is said to increase gasoline mile- age by eliminating the wearing drag of trans- mission bands 75

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Popular Science Monthly Hints on Repairing Your Auto ' K JHENEVER you need a scraper in connection with repai:s about your car and have no sharp tool at hand, you will find a discarded piston ring will usually do the work very well. It makes an excellent tool for scraping a bearing and for cleaning carbon from cylin- der walls and is an aid in finishing many jobs quickly and accurately. The ring may be used whole or br ken in half. Use both hands in handling it and cut with either edge of the ring, as in Fig. 1.—J. W. R. MOTORIST who did not feel in- clined to dismantle certain parts of hi car to insert spacing washers in order to take out the rattling play, par- ticularly at the spring shackles and steering knuckle, found that washers avoid having to do it, wedge the cap and the transmission case apart, as shown in Fig. 10, and pack with strands of candle wicking.—L. Y. RR SPoRe removing a leaking tire from th rim, mark the casing and valve stem, as shown in Fig. 5. Then, after re- moving the tube and locating the leak, lay

made up of pieces such as the one shown in Fig. 2 served satis- factorily. He cut a number of pieces of sheet metal of this shape, in- serted them between the parts from opposite sides, and bent over theends to lock them into proper place. —R. H. KAsPer.

BENT TO FORM HANDLE 3. Petcock handle O TEST the oil level on a Ford without the usual difficulty of opening the petcock by hand, make the tool illustrated at Fig. 3,

* from a section of dis- carded brake rod about 2 ft. long. Simply bend one end at an angle to serve as a handle. The regular clevis at the other end, when slightly hammered together, will fit over the petcock handle and enable the handle to be turned without the ordinary inconvenience, then there is no excuse for not testing the oil level regularly. A dis- carded brake rod can be had for the asking at almost any garage.—G. F. S. Ww EN too much play exists in the cone clutch of your automobile, a repair can often be made quite simply by using a hack- saw blade as shown in Fig. 6. The blade is forced between the cone and the cone clutch lining in such a way that the leather is sub- stantially built out. Thesaw teeth serve the purpose of preventing the blade from work- ing out, and the leather is raised sufficiently to — +4 tight seat when the clutch is let in.—C. M. —— the gasket on the ball joint of a Ford transmission czse is torn, it is o take out the rear end in order to renew the gasket. This is a time- consuming job and one the average car owner dis- likes to un- dertake. To CANDLE WICKING 10. Ball joint gasket 76 TT eT a

4. Reducing noises in brake rod joints HOOD CATCH 7. Simple method for locking hood i lage use of bolts and lock washers wil] often overcome annoying brake rod noises. The usual loosely fitting clevis ping used at the ends of brake rods have suffi. cient shake to cause a certain amount of unnecessary noise and wear. One owner overcomes this by substituting machine bolts, nuts and lock washers, as shown in Fig. 4, in place of the clevis pins and split cotters. When the bolts are perceptibly worn, and there is any indication of noise, they are renewed.—H. A. L. HE electric alarm illustrated in Fig. 9 is a useful device to prevent backing an automobile into tke rear of a garage. The contacts are placed in two recesses prepared when the

concrete floor is laid, or chipped out

HOOD

pooeroren= ee eeee a eee i

*—cONnTACTS~ 9. Electric alarm for backing car

GREASE-GUN

PIPE. BUSHING _ FY SOLDER 11. Greasing hubs mo. "a4 . i. eg

g ( t' 4 1 t t I ¢ f 1 (

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O ashers will brake rod clevis ping have suffi. amount of One owner zy machine 3 shown in Ss and split erceptibly lication of A. L. strated in (0 prevent . tke rear are placed when the ipped out erwards, se recesses bridged by oy 4 in, -oden ks. The ight of backing closes an tric bell 1it and the is then back just igh more elease the ing con- stop the -—C.F.G, ,-YLAND ‘ist was > a ditch lision in left front S car was glancing } Car ap- at an uble bar ff center off a car eel. This ny repe- ncture, a air that ea quill, ole in its ouncture leak out of a car llisa imber of ared for. a small A pipe THREAD TO FIT GREASE~ GUN ubs Popular Science Monthly 75 Home Workshop Arthur Wakeling, Editor Easily Built Crib and Play Pen N EVERY home where there is a small i baby, a combination crib and play pen is one of the most necessary and useful p’eces of furniture. It can readily Le moved from room to room, away from a drafty window, out on the porch, into the yard, on the roof of an apartment house, or wherever needed. If it has an adjustable mattress frame, : like the one illustrated at the right, it can be used with equal convenience in place of a regular high bassinet at night and as a screened-in play yard for the baby’s wakeful hours. In construction the crib shown is little more than a series of quickly and easily made frames covered with gal- vanized steel wire cloth, such as is used for fly screens. The 7% by 134 in. stock for the frames may be of cypress, pine, whitewood, spruce, or any other soft wood. All the joints are doweled to- gether. The largest frame, which is the one for the back, is 2 ft. 1 in. by 4 ft. in size; the front consists of two 12 in. by 2 ft. 1 in. frames, and a third 2 ft. by 2 ft. 1 in. frame makes the door. A variation. of this ar- rangement, shown directly below, is a door made in two parts, hinged to- gether, the lower section being hinged to one of the side frames. This design is convenient whenever the crib is to stand alongside an adult’s bed at night, because the upper door can be partly, if not wholly, opened without pushing the crib away from the large bed. The end frames are 2 ft. 14 in. by 2 ft. 1 in. Their vertical members are % in. square See OR DOLPHIN x oll \ — MATTRESS FRAME, ——_ L-IRON BRACE ’ The general construction of the crib and ils details of the corners and frame joints instead of % by 13% in. The folding top consists of four frames, each 12 in. by 2 ft. 2 in. in size. A 2 by 15 ft. piece of galvanized wire cloth is required for covering. It is tacked on the inside of all the frames except the top ones. where it is tacked on the outside. It goes in a shallow rabbet in the top frames, and the edges are covered with a thin strip of beading set flush. The rabbets can be omitted and the wire and beads planted directly on the top, but this is not nearly A screened-in combi nation é = crib and play a 2 pen with fold- : ; ing top as neat in effect. On all frames except those for the ‘top the edges of the wire are covered with small beads, as shown below at the left. The two center frames of the top are hinged to the outer frames with ordinary butt hinges, but special hinges have to be used for hinging the outer frames to the body of the crib. Commercial dolphin hinges, such as are shown, or homemade rule joint hinges may be used. Double- acting screen hinges 134 by 134 in. are particularly good for this purpose. The bottom frame, of 2 ft. 14 in. by 3 ft. 104% in., may also be covered with netting. The mattress frame is a trifle smaller and is corded, as indicated, or covered with duck. It is attached to the lower frame with 14-in. brass rule joint stay or support hinges, which can be purchased at any large hardware store. The ornamental wheel brackets are cut from hardwood and are doweled to the lower frame. Regular bassinet wheels of solid wood, pressed steel, or wire, with A very light spruce pla » the details Take ee Re ane heavy rubber tires are used, as preferred. The crib is finished with one enamel undercoat and two or three thin coats of white or cream enamel. Complete details of this unusually fine crib are contained in Blueprint No. 26 of POPULAR SCIENCE MONTHLY’s series of blueprints, which will be sent to any reader at a nominal charge of 25 cents. Simple Play Pen Requires Only Six Light Frames A SIMPLE play pen can be made with only six frames. How this is done is illustrated in the photograph and details below, which show one designed and built by Mr. E. E. Scott, of Pittsfield, Mass. ; : This play pen is 48 in. long, 26 in. wide, and 25 in. high above the wheels, which are doll carriage wheels with “oversize” tires. The ends and sides are constructed like ordinary window screens except that.an end-lap joint is used-for the sake of strength. The sides are further reinforced with inter- mediate braces, as shown. Spruce is used on account of its lightness. Make up the frames, chamfer the edges to improve the appearance, and tack on ordinary wire fly s¢reen. Half round bead- ing, obtainable at almost any lumber yard or sash-and-door mill, should be nailed over the edges of the wire. The sections should then be joined with three wood screws in each joint except the lower half of the hinged section, which may be held with two screws at each end. The upper half is hinged to it with three hinges and suitable hooks are provided at the top. Construct a pair of trucks of maple or other hard wood, as shown, and attach Agar" (2) END FRAMES Details of frame, trucks and corded springs for play pen shown below at left them to the bottom frame with heavy wood screws 3 in. long. It will not be necessary to use axles the full width of the bed; they can, indeed, be large spikes driven into holes bored through the wheel supports to a diameter 1/32 in. less than the size of the spike, or heavy wood screws can be used. ‘ Home Workshop Department of Popular Science Monthly 77 j | eae eek ena ET none Soe phi. IEE ERATE Ue See CTD ee mee Vane IIS RE EOeO TS Ce nee ee ee Oe ee ee eee e ngs ge - as e " ie icicle acest namie Abilis: sp _— See

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serena Oger Neat 90 ee ooo eeeccaaererne:.F eRe ch ee eee oa oe ie ee gor a cet Ce aN aN Sen ee mpm a: eee ee ger Di NSA ae Pe taal acta neaiinieia ie Tac : ’ Da PAiaa ees a ae oat ar SSR OI 16 Popular Science Monthly How to Build a Supersensitive Set Cheaply OUDER. signals, greater sensitivity, more selectivity, more compact sets —these are the rallying cries of radio experimenters. Each new set has thousands of adher- ents. Some radio fans pin their hopes on the old reliable single circuit regenerative receiver; others boast triumphs achieved with single tube super-regenerative receiv- ers. Many experts stand by the triple cir- cuit regenerative set, while others extol the virtues of the Reinartz, the Cockaday, the neutrodyne, the Flewelling, and the other more recent circuits. ~ The average radio enthusiast undoubtedly would like to try them all and then make a selec- tion, but cost, and lack of time and technical skill prevent. To lend a helping hand to Home Workshop readers in just this situation, POPULAR SCIENCE ~~ MONTHLY has es- tablished an ex- — ;. perimental work- \4 Ms : shop in which ‘SB. = receiving sets of SS A various types are being built and tested. From month to month I shall give complete information regarding the construction and opera- tion of these sets, together with all pos- sible information regarding their advan- tages and disadvantages. As the first of this series I have chosen the Flewelling circuit, since for the sum expended and the ease with which it can be constructed, it is easily one of the foremost of the supersensitive receivers. The Flewelling circuit, as Jack Binns explained in POPULAR SCIENCE MONTHLY last month, may be looked upon as akin to the Armstrong super- regenerative hookup. As far as the actual arrangement of the parts of the circuit is concerned, there is very little difference between the Flewelling and the single circuit regenera- tive receiver. The only extras are a bank of fixed condensers and a variable resistance of the same type ordinarily used as variable grid leak resistances. With the exception of the slight change in the wiring introduced by this additional apparatus, the circuit is exactly that of the single circuit regenera- tive receiver. Unique Coupler Used for Tuning In order to cover the range of wave- ° lengths now used by broadcasting stations, the tuning elements should consist of a pri- mary coil of about 50 turns of wire shunted by a 28- or 43-plate variable condenser, preferably of the Vernier type, and a tick- ler coil of from 75 to 90 turns. As it is not possible, ordinarily, to obtain or make a variocoupler having 75 to 90 turns on the rotor for use as the tickler, most Flewelling sets have used honeycomb coils as the inductances. While these coils serve the purpose, they are rather cumber- some to use, since they must usually be mounted on the front of the panel. They also have a disadvantage in distance work caused by the capacity of the hand in mak- ing adjustments. . This is more pronounced than when a tuning coil of the variocoupler type, mounted in back of the panel, is used. The special type of variocoupler used in the set illustrated can easily be made. The stator is made in two sections, each section By Joseph Calcaterra Of Popular Science Monthly’s Radio Staff being wound independently with 54 turns. The lower coil, which is tapped, is shunted by the variable condenser, and used as the tuning coil, while the upper coil is connected in series with the rotor winding to form the tickler. The first tap is taken at the sixth turn of the lower coil and a tap is then taken at every six turns thereafter, making nine in all. The taps are led to the tap contacts of an inductance switch. This can be one of the new type having all the contacts in the rear of the panel, which eliminates the trouble of drill- ing independent holes for switch points, or a regular switch, with contact points on the panel. In either case the nine taps at every. ———————— ela sana caneae The completeFlew- elling receiver is shown in the small - -TICKLER ROTOR © illustration above, C) + ns —_L T- and the back of the panel in the larger view. Note the uniquetuning unit, the two vari- able resistances, and the small con- denser “‘bank’’ nt ey CONDENSER ; ANK - ; RESISTANCE AERIAL = 4 08+ 92 PHONES oR! =--R The hookup shown in two ways. The lower diagram corresponds in arrangement to the wiring of the set itself , six turns will be sufficient, since the con- denser will easily provide the finer tuning, The size of the tube used is not very im- portant and may be 3 4 to 4 in. in diameter, The length of each section is 214 in., making a total for the stator of 414 in. The rotor may be any convenient size, V4 to 34 in. less in diameter than the diam. eter of the stator tube. The wire used for winding both the rotor and stator sections may be any size between No. 24 and No. 20 single cotton covered. The rotor is pivoted so that it is between the stator windings, In order to concentrate the windings ag much as possible, it is desirable to use a bank winding of two layers on the stator coil. This type of winding is no more diffi- cult than the ordinary method of winding single layer coils. : Start winding the coil in the usual man- ner for the first three turns. Then, instead of winding the fourth turn next to the third, carry the wire up at the end of the third turn and wind it so that the turn lies on top of and between the second and third turns. The fifth turn is brought down at the end of the fourth turn so that it lies be- side turn No. 3. The sixth turn is then brought up so that it lies on top of and be- tween turns Nos. 8 ae, ; and 5 and beside No. 4, and so on. In making taps you will find it easier to tap off only on the turns of the top layers. If you have ; started the top layer j with the fourth turn, each sixth turn will be on the top layer. The taps can easily be made by twist- ing the wire in a small loop at the point where the tap is to be made, the wire at that point, and soldering the twist so as to prevent it from untwisting. Care must be taken that the bottom turns are wound on tightly in order to prevent any possibility of the top turns’ wedging down be- tween them. The taps should not be taken at exactly the point where the wire is brought down from the top tothe bottom layer or vice versa but should be taken a short distance after the wire is brought up to the top layer or a short distance before it is brought down to the bottom layer. Drilling for the Rotor Shaft A short piece of brass 1/16 by % in., or any other convenient size, is bolted on the front inside part of the stator tube sections and another piece is placed at the back, to keep the two parts lined up and together. Holes the size of the rotor shaft are drilled to provide bearings for the rotor. The sec- tions are assembled after being wound. If the new dry-cell tube that operates on 3 volts and consumes .06 amperes is used, it will be necessary to provide three 1)4- volt dry cells in series to provide the fila- ment current. In this case the ordinary standard type of filament rheostat cannot (Turn to page 92) secnastinsinsanasveacai — 78 Home Workshop Department of Popular Science Monthly A gaamhlindg a High Dawrar Mirrncrnna baring —

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ply » the con- er tuning, L very im- diameter, 1., Making lient si the dima e used for r sections nd No. 20 is pivoted windings, ndings ag to use a he stator nore diffi- f winding sual man- 1, instead 0 that it f and be- Nos. 3 side No. taps you easier to ' on the he top ou have op layer ‘th turn, urn will the top The taps sily be y twist- - wire in loop at nt where is to be baring — ft in., or on the ections ack, to gether. drilled he sec- nd. ates on $s used, se 14- ‘ he fila- dinary cannot Home Workshop Department of Popular Science Monthly 77 How to Identit By James S. Godfrey mahogany when you see them? And do you know offhand the differ- ence between a piece of burl walnut veneer and a crotch figure, or what distinguishes fiddleback from striped mahogany? To know these two greatest of cabinet woods intimately and recognize them in their various forms and figures is a valuable accom- plishment. Everyone who is in- C=: you always identify walnut and Microphotograph of the end ain of black walnut magni- fed 7% times (above) and the flat grain of walnut (at right) Photographs furnished by Forest Pro- ducts Laboratory, U.S. Forest Service terested in furniture—and who is not?— should have this knowledge. The home worker, who has little choice but to use either walnut or mahogany for his finer pieces of wood-craftsmanship, is certain to find useful every scrap of information he can pick up regarding these woods. The first essential is to be able posi- ty Walnut and Mahogan tively to distinguish walnut and mahogany from other woods. To depend upon the super- ficial appearance of the finished surface of the wood is hazard- ous. Even experts can be de- ceived momentarily by cleverly treated substitutes. There is, however, a reliable test for both walnut and mahogany in the size and arrangement of the “pores” or small tubes found in the cross section or end grain of the wood. These can be seen with the unaided eye although a magnifying or reading glass is useful in studying them. If possible the end grain should be sliced very smoothly with a keen blade before examination. Microphoto- graphs of the end grain of black or American walnut and true mahog- any magnified 7144 times, appear on this page. They are published through the cour- tesy of the Forest Products Labor- atory, Forest Service, U. S. Department of Agriculture. Typical panels of burl walnut veneer (above at left), crotch veneer (at right); stump figure (below at left), and sliced wood (at right) Mr. Arthur Koehler, who is in charge of the Office of Wood Technology, very kindly lent his assistance ~ in the preparation of this article. Note carefully the size of the pores and their arrangement. Then turn to page 105 . and examine the microphoto- Specimen mahogan at left), fiddleback (at right); raindrop veneers—crotch figure (above c ure (be- low at left), and striped (at right) graphs of yellow birch and red gum. These two excellent hardwoods are the two woods most commonly used as sub- stitutes for walnut and mahog- any. Their texture in the cross section is so very much finer, however, that there is no chance of mistaking them for walnut or mahogany. Pores Always Visible These characteristic pores of walnut and mahogany appear on the flat surfaces as fine but rather long lines, as seen in the two photo- graphs of the plain wood on this page. When the log is cut diagonally, as the specimen of wal- nut shown in the upper illustration on page 105, the pores appear as short dashes, but — they are still quite distinct. In fact the pores are al- ways present, no matter how bold the figure of the grain or how light or dark the finish. (abov: Popular Science Monthly Flat ~— of mahogany 'e and microphoto- graph of the end grain (at the right) While more than Peostomnnha tursiched, by Rovest sixty different spe- Products Labqatory, U. cies of timber have been sold as mahogany at one time or another, the lumber now ordinarily sold as mahogany is either true mahogany from tropical America, “African mahogany,” or “Philippine mahogany.” The first two are distinguished by a dark amber-colored gum partly filling the pores. True mahogany has continuous, light con- centric lines on the cross section usually from ) to in. apart, as shown (enlarged) in the microphotograph while ‘African mahogany”’ never has these lines. ‘‘Phil- ippine mahogany” has no dark masses of gum, but has fine white tangential lines that under the magnifying glass appear as rows of small openings filled with a white material. Both walnut and mahogany furnish splendidly figured veneers. These are used for decorative purposes in fine furniture and cabinet work. Four typical figures of each wood are shown on this page. There is a speci- (Turn to page 105) 79 ft MW | A) 9 — a 0 HU Nm 1 Sr. phe: Deakas a = a ne in le ‘ H it i : H i { “ Li {|

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78 Home Workshop Department of Popular Science Monthly Assembling By Ernest Bade, Ph.D. O instrument is more important in the home laboratory than a micro- scope; few instruments are more expen- sive. We therefore asked Dr. Bade to design one that could be made without much technical skill or any large outlay of * money, and the result is the remarkable instrument described in this article. —THE EDITOR. AKING the stand for this micro- M seope is really the most difficult part of the work. In this case toy construction parts have been used but plain metal strips or wooden parts will serve the purpose. The base is a flat plate with two short arms rising from the center of both long edges. The tops of these arms are provided with holes through which a rod is later passed to carry the upper part of the micro- scope. The upper part consists of a shelf, a hol- low square for holding the microscope tube, and a micrometer screw for moving it. Care must be taken that the shelf for carrying the specimen Sct - Rear view of the finished microscope (above) and the instrument tilted to How the objective lens is made (above) and mounted (at right) obtain direct light (at right) rack with teeth that mesh with the worm. Therefore, by turning the worm, the holder can be raised or lowered as desired. The microscope tubes are made of heavy paper or cardboard. The outer and larger tube is attached to the hollow square so that it is immov- will lie directly beneath the tube. For illumination a large hole must be left or made in this shelf since a mirror is placed on the base to light up the object that is tobe viewed. The shelf is also provided with an upright to which the micrometer screw is attached. In this case the screw is a toy’ worm gear, although a rack and pinion could have been used as well. The shelf is hinged to the base by the rod already men- tioned. The sliding tube holder, which is held in place by two rods on which it slides, has a Taken with the microscope, this photograph shows the structure of a piece of wood en- larged approximately 75 times a High Power Microscope able. Into this a short tube is fitted; it must be quite firm. The lower end ig covered with a cardboard ring through the center of which a small hole is burned with a hot needle. This is the nose piece, or ob- jective. For the eyepiece, or ocular, an- other tightly fitting tube is made, as long or longer than the outer tube. The lens for the nose piece must have qa short focus, if it is to enlarge to any great extent. Since such an objective is excep- tionally expensive, it is just as well to make a substitute at home, although the results will not compare with those obtained by the use of a real lens. Take an ordinary thin glass rod or a glass tube and, holding it over a bunsen burner, melt the end into a small round ball. Draw the melted ball away from the rest of the glass with a pair of forceps, taking care that the ball remains perfect. This ball is to act as the lens in the nose piece. It is more than probable that the first ball will not be perfect, nor will the second or third, but at any rate try them and if they do not work, make some more. This is quite easy to do, does not take long, and one out of a dozen will do the trick nicely. The glass ball is pasted over the hole burned in the disk. Take care not to soil this ball and do not paste any paper over or in back of it. The eyepiece can be any short focus lens, a focus of approximately 2 in. being sufficient. Attach this to the lower part of the upper inner tube and begin focusing by gently raising or lowering this tube until a large field of light is obtained. It may be necessary to lift the eye 6 in. or more from the eyepiece to get results. By experimenting with several old lenses at hand, you may succeed in making a compound eyepiece. Pipe Frame Supports Motorized Home Workshop Bench By Frank N. Coakley OMPELLED to use a corner of the cellar or garage or some equally restricted space, the amateur machinist is often at a loss as to the best method of arranging his bench and machine tools. A compact and effi- cient layout, making use of a framework of pipe and pipe fittings, is that illustrated in Fig. 1. The combination bench with a 10 in. lathe, a 10 in. drill press and a bench grinder take up less than SIDE VIEW Fig. 1. shaft. REVERSE AND FORWARD CLUTCHES DRIVING PULLEY f =| ,-1 Ye’ SHAFT > CLUTCH LEVER STANDARD SHAFT HANGERS 40 sq. ft. of floor space. For the lathe shown, a the standards are 6-in. pipe. A smaller machine cme | 3 aah would not require such heavy supports. Stand- ard shaft hangers gener- ally give better satisfac- tion than the usual amateur arrangement of babbitted pipe tees. The bench frame is connected to the ma- chine stand by means of 8-in. pipe flanges bolted to the 6-in. standards. FRONT VIEW Side and front views of the motorized workbench arranged for a 10-in. bench lathe, a bench drill, and a grinder, together with the necessary counter- The entire bench requires less than 40 sq. ft. of floor space Popular Science Monthly The bench legs are 3-in. pipe. The outside board (Turn to page 101) BI Qua of the bench top is 134- | -_

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Popular Science Monthly 79 itted; it end is ugh the ed with e, Or ob- lar, an- as long i. _} : a. tit Z , | WAN a [Asse TE MN MG ) Wilts ar \\\\ wgoee Ss bad a t have qa — ny great te KW i | ra glass _ burner, |. Draw st of the sare that is to act first ball >cond or Sa FAN i Cae Ca . a a ct a dean | This Beautiful Book on d if they This is tlie ts yng, and 5 me Wood Finishing the hole t to soil per over ‘ E a rt focus E n. being r part of 7 ye, wert — C= complete instructions for finishing all poe tees pelt aM id new. It may Explains just what materials to use and how to app y st , e ~~ - Re expensive soft woods may be finished so they are as beautiful as hardwood, | lenses book is the work of experts—illustrated in color. Gives covering capacities, etc. aking a nch jo H N SO ea Johnson’s Wood Dye is for the awe connie onan oe Sea a re 6-in. sive softwoods may be finished sot a are - beau - on - ac a8 HA machine J . d D is very easy to apply—it dries in 10urs an t ohnson’s Wood Dye is very easy j gre : smudge—penetrates deeply bringing out the beauty of the grain. Made in fourteen rs gener- popular shades all of which may be easily lightened, eS satisfac: darkened or intermixed. Full instructions on every ie: palpi Wining ma eee ian a2 label. | “The Wood Finishing Authorities” i ees. * ska eck on Wend Peabtetnd ond teeeee’ Bonutifying. i on oO nis ° agg Ss. C. JOHNSON & SON , sepiaaoarihe - the =ma- , m eases WANE... .. 0.5.0: 5cccecedsecbouesines means of “The Wood Finishing Authorities z 8 a RACINE, WIS., U. S. A. Maa PS... .0snseh agen i eng i GNM os cc cuan shes tacoweenaaeennel ij WEST DRAYTON SYDNEY, ff 3 raplin! eRCANADA MDDX. ENGLAND rte j lie Oe OE a, coos nbdepenns sce vencekiahl oaepteunee D is 200 ee Se ee ee ee > 101) Popular Science Monthly 81 +H lh,

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PE Ss ee —7eegas te 80 ————— that all machinists and bench hands meet in the ordinary course of their shop work, the 6-in. bench grinder illus- trated is, I feel confident, one of the most unique and useful machines of its kind. Resembling in main essentials an ordi- nary bench grinder, it is a many-purpose machine. It not only serves for the grinding of lathe and other machine tools, but it easily accomplishes the side surface grinding of small work within limits close enough for most practical purposes, and, with equal facility, handles light hand milling operations. On occasion it also does drilling, wood turning and buffing. A glance at the assembly drawings below will tell any machinist the possibilities of the machine much quicker than columns of explanation. While it is in no way in- tended to replace larger and more accurate machines, the grinder has a wide field in performing small odd jobs that are essen- tially bench operations—the kind of work that often ties up a large and expensive ma- chine that could profitably be used for more important purposes. Valuable for Automobile Repairs - Aside from its value in the shop, this grinder obviously is an exceptionally useful tool for the home ma- chinist, model maker and automobile repair man. They are fre- quently handicapped for lack of facilities for doing the surface grind- ing and milling that is so easily accomplished with this grinder. The base casting, 1, which is detailed on a following page, is Pre: the countless small grinding jobs eee athe So acetal wre wade : EAS ap es oer ~ ms _ ms _ 7 9 5a vine 7 speci epizemenrene me etrvmrn tater ee et al mr? ms — se pieuinenlig 2 ~ Pp mn RO RRR Rm r awe nt mE : ga ces TLE By B. R. Wicks Machine Designer and Shop Foreman The complete grinder, showing the grinding table in use. he table is supported, when necessary, by an adjustable leg, indicated in e end view below wood turning and turned pattern work. How this is accomplished is indicated dia- grammatically on another page. The spindle is not only equipped to hold a 6- or 7-in. emery wheel, but also has a No. 1 Morse taper for use in various ways. The auxiliary arbor, 7, of tool steel, is inserted in the main spindle for holding small wheels, milling cut- ters, saws and the like when necessary. Perhaps the most un- usual feature of this bench grinder is the adjustable slid- ing grinding table for side surface grind- simply a development of a conventional bench grinder base. It is cast iron, finished asmarked. The pattern can be somewhat simplified by making the bearing for the motion link belt shaft, 37, separately, and welding or screw- Hea asec eg OR ONE TNE OO AIOE OS “ ing it in place. The spindle, 3, which is machine steel, runs in a bronze spindle bush- ing, 2, and is keyed at one end to a special cast iron driving pulley. This pulley, 9, is de- signed to take a face- plate up to 12 in. in diameter for a con- ing table with its supporting leg appears in the end view. _ ie erinder mete, winiats 200, neg pe on Sonata Pages, are assembled. . : t ° “ete . . 4 : hee siderable variety of al tool rest for ordinary tool grinding, is shown in the front and top views, and the special swivel Note the table operating lever, 38 A Six-in-One Machine of Simple Construction that Does Tool and Side Surface Grinding, Hand Milling, Drilling, Wood Turning and Buffing ing, 41. It can be set at an angle either way, and is provided with T-slots and stud holes. Handy attachments for straight and taper work may be added, and the table serves for either grinding or milling. The table spindle, 42, is graduated for convenience in setting the table at an angle, and is locked in relation to the table slide, 21, by the binder, 29, and tightened by the handle, 25. The grinding table is sup- ported by the adjustable-support shown in the end assembly view. This is to relieve the strain on the cross slide, 19. The table slide, 21, is a sliding fit in, and feather-keyed to, the horizontal cross slide 19, and a screw feed is provided by the simple arrangement shown most clearly in the top assembly view. Swivel and Slides Give Flexibility The cross slide, 19, travels in the cross slide swivel, 18, which is graduated and can be set at an angle. This swivel is held in position in relation to the frame by the binder, 15. The cross slide is held in rela- tion to the frame by the screw 12, and thrust block, 13. It will be noted that the alinement of sliding parts is maintained throughout by keys and keyways. Both 19 and 21 have 8/16 by 3/16-in. feather keys, and the grind- ing table spindle, 42, a %-in. square key that slides in the head of 21. These keys must, of course, be perfect sliding fits with- out any shake in their keyways. The back-and-forth stroke of cross slide 19 is controlled by the operating lever, 38, through the medium of a short shaft, 37, and a motion link, 30. Two dogs, 35, which slide on a flattened rod, 34, and are locked in place by two 3/16-in. screws, 36, regulate the travel of the stroke. In case of emergency, a useful and fairly accurate lathe for small work can be obtained by mounting the grinder, a toolpost, and a tail- stock of some kind upon a firm support. A bench machine of this type should preferably be mounted not directly on a wooden bench but upon an iron plate. Work-holding and guiding attachments of a type similar to those used on larger machines can readily be made up or improvised as occa- sion arises. Some work will require a small angle plate. One 1\% by 2 in. is a good size. A straight edge or an adjustable straight edge for taper work, 214 in. long, is (Turn to page 86) The convention- Better Shop Methods Department of Popular Science Monthly

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[UL ) — ee eee eee eee a ee Ee ee ee ee SESE EEE oo Eo ee Popular Science Monthly 81 TOC RR } j Ha H HaB : Bares tie) es ing, either d stud raight id the lling. ed for angle, slide, by the $ sup- wn in relieve TIC TACTIC LAL CARA n, and s slide yy the rly in ity . Cross nd can eld in yy the n rela- » and ent of ut by have grind- e key > keys with- a You Can’t Beat a Starrett Caliper id are Starrett Calipers and Dividers are famous everywhere for oe their fine workmanship, reliable accuracy and the sensitive ay “feel” so necessary for precise measurements. ‘k can és r the Whatever your work, if you have a need for Calipers or Dividers = i you can find exactly what you want in the Starrett aoe pues. ne of | special features, sizes, prices, etc., are all fully covered in the Star- 7 > rett Catalog No. 22“W”, We will be glad to send you a copy if rect] aged your hardware dealer can’t supply you. _" THE L.S. STARRETT CO. ATHOL, MASS. nts of The World’s Greatest Toolmakers Manufacturers of Hacksaws Unexcelled those . —_ chines " \ ide up ; © O~ iC) occa- ( Some 1arre C 0) ire a : aces _ One good - edge , : E able taper ng, is 86) at Popular Science Monthly 83

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nM RLU RTI ane mem ee mCP RB Att Dp AR ERRORS: merece NEF Piha ag EA I Ee Reg ne EH ec wes eas — Ae pene ae a map oe I mt itt Res aces eee ee ated sere scott non te oaeinticetite or re ~ eR Te errset ensteneen 82 Better Shop Methods Department of Popular Science Monthly From Machine Shop Apprentice to Production Engineer HIS is another striking message of encouragement for mechanics that came to POPULAR SCIENCE MONTHLY in its recent contest, ‘‘How I Got that Better Job.’’ The writer, who is well known and contributes frequently to technical magazines, asked, for personal reasons, that his name should not be published.— THE EDITOR. HE man who is constantly looking for better methods is the one who is going to get the better job. The truth of this has been indicated by little flashes here and there along the road of my own ex- \ perience. My decision to go after the better job was prompted by my spoiling some valu- able and important work in my ’prentice days. I was planing three surfaces on twenty duplex steam pump bodies, ar- ranged in a triple line on the bed of the ma- chine. These had to be exact in total height and in relation to each other. That day I must have been dreaming, for suddenly I woke up to the fact I had cut down too far and spoiled all twenty castings. Impetuous by nature, I got my coat and, ready for the road, approached the boss. “‘Where are you off for?” he demanded. “Home,” I answered. “Sick?”’ * “T guess so. You see, I’ve spoiled the castings I was working on, so I thought I’d save you the trouble of firing me.” After a pause of several years seemingly, he said: “You young fool, take off your coat and hat, and throw those castings into the scrap heap. Put another batch on, and heaven help you if you spoil them! And remember this,” he continued: “The man who never spoiled anything, never made anything, but see to it that you do a better job than you ever did before.” That night I made up my mind to prove to my boss that I could do a better job, with the result that in two weeks I was able to suggest to him the idea of a fixed step gage that resulted in quicker work, with less chance of error. From then on I decided to find better methods of doing things. For example, there was often confusion and wasted time in handing out orders, so I suggested a series of six files mounted on a board, with the most important rush job mounted on file No. 1. The men were told to take the order on the lowest number. Ingenuity Solves Many Problems — On another occasion a leak developed in the water main but it was not desirable to shut the waier off to make the repair and I suggested a way it could be done. The next time it was a new method to slot the heads of round head screws, of which we made a great number. I designed a simple form of milling machine with a sliding car- riage and a boy in the tool inclosure room operated it in his spare time. “Do as quickly as you can, all the opera- tions possible,” became my motto. We then had a number of shafts to turn, which required two cuts. The lathe operator used one tool at a time, but I rigged up a double toolpost, one tool doing the roughing cut; the other, the finishing cut. This same idea was developed in various ways, as many as six tools being used at one time. I also ap- plied the idea to milling cutters, placing them in gangs wherever I could. About this time I moved up to the drafting office, spending my time on jig and fixture design. In the case of a cylindrical cast- ing that had eight evenly spaced holes around the circum- ference, I cut the production time way down by the use of avery simple fixture. For some unknown reason the firm was content to lay out each casting separately before drilling and it took a man 15 minutes to lay out one piece. I mounted the casting on an arbor, which was inserted in a block having a tongue on it. This in turn was mounted on the main jig casting, which had eight radial slots cut in it. After drilling one hole, the operator, a boy, not a man, pulled the block out of the one groove and moved it on to the next until all eight holes were drilled. Cutting Down Handling Costs After several years in the drafting office I was made assistant chief, and later moved to another firm as chief. In this plant a huge basement was used for storing stock parts. Unfortunately, there was a brick wall partitioning off a certain part of this basement and, when it was necessary to take parts from one section to the other, the usual practice was to put them on a hand Ready to quit Several tools are used simultaneously when- ever possible, as in the case of this gang milling set-up truck, take them up the elevator, across the plant and down another elevator. “Why not knock a hole in the wall, and make an archway?” I thought. The sim- plicity of the idea was almost ridiculous, yet it saved a large sum of money. I left that firm to go to a position as manager of the works; then, still in search of better things, I moved on to engineering service work. My advice is: Keep your eye on the better job. Read good magazines. Keep up with the times. Don’t work according to the time clock. Get away from the idea you are giving your boss too much time and too much profit. We are always learning, and if we keep an open mind, we always will learn—learn to do and to get that better job. Brazing High Speed Steel Tips on Lathe Tools SF igaek shops could get along with fewer solid lathe tools made of high-speed steel if it were thoroughly understood that the brazing of high-speed steel tips to ordi- nary machine steel or mild tool steel bodies is a relatively simple process. The prin- cipal difficulty comes in the slipping of the tip from its seat before the flux has set, There are four methods of brazing that can be used in the average shop; brazing by the use of a commercial brazing compound, heat- ‘or fire-welding by using a flux com- posed of a mixture of powdered borax and steel filings, brazing with a thin sheet of copper or brass and powdered borax as a flux between the point and the shank, and oxy- acetylene welding ; with any suitable jal Je flux. a, / The shank is usually a piece of machine steel cut from commercial barstock,although _. mild tool steel will TP Pound on ready for give better service. The end of the shank is milled to a suitable depth and the tip, which is high-speed steel, is cut from bar stock. It should be surface ground on one side to present a clean face for brazing. If the surfaces are not thor- oughly clean, the tip is apt to become loose, The brazing compound is placed between the tip and the shank and the. two are bound together with soft iron or copper wire. Brazing is accomplished in a high- speed steel furnace, preferably one with a chamber for preheating and another for bringing the tool up to the proper tempera- ture for hardening. If this type of furnace is not available, the tools may be preheated in any furnace. Preheating is necessary to enable the flux or brazing compound to flow readily over the entire surface, and also to avoid cooling down the high-speed furnace by the intro- duction of cold steel. . The parts, wired together, are placed in the first furnace or chamber and brought up to a dull red heat. When removed, the tip should be tapped lightly with a hammer to distribute the flux evenly ‘between the surfaces. The tool is then placed in the high-speed furnace and brought to the cor- rect heat for hardening. Care should be taken to see that the tip does not float from its seat while this is being done. When the correct temperature has been reached, the tool is removed, cooled and ground to shape.—H. L. WHEELER, Westwood, Mass. Simply Made Depth Gage Rage simple depth gage illustrated has a certain originality about it that will appeal to men who make their own tools. The body is 3% in. square steel about 3 in. long. Three holes are drilled in it, as in. locking screw. The depth rod and locking pin are only short lengths of -in. drill rod. The locking screw has a_ tapered point.—C. M. W. ‘ shown, one of ot DEPTH ROD-& DIA them being , a Ff tapped for a 3/16 Better Shop Methods Department of Popular Science Monthly

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eel Tips | With fewer high-speed rstood that ‘ips to ordi- steel bodies The prin- ping of the ux has set, razing that brazing by compound, 2 flux com- | borax and in sheet of borax as a

a ready for ting 0 a suitable speed steel, | be surface . clean face e not thor- come loose, ed between 1e, two are or copper in a high- one with a nother for or tempera- of furnace > preheated ble the flux sadily over oid cooling ’ the intro- 2 placed in id brought moved, the a hammer tween the ced in the to the cor- should be float from When the ached, the ground to ood, Mass, Gage ated has a _ that will wn. tools. el about 3 d in it, as one of . being for a 3/16 ‘ing screw. lepth rod cking pin nly short ; of %-in. od. The r serew _ tapered —C.M.W.

Popular Science Monthly 83

Write us a post card— and we will send you free this 52 page catalogue of radio sets and parts. It also contains explanation of radio terms, map and list of broadcasting stations and much radio information, including an explanation of successful hook-ups and circuits. You will be amazed at the low prices |! Ward’s quote. A complete set for $32.50 & | equalling sets at $60 elsewhere—a $23.50 =< set that under favorable conditions has = ius of 500 miles and more. ' ports catalogue contains everything for the expert and amateur. Complete sets and every improved part for building sets, all the most up-to-date de- vices—at the lowest possible prices. Headquarters for Radio Montgomery Ward & Co. is headquarters for Radio, selling se heen direct by mail without the usual ‘‘ Radio-profits.’”’ Why pay higher prices: Ward quality is the best and the prices will often save you one-third. Everything sold under our Fifty Year Old Guarantee,— Your Money Back if You Are Not Satisfied. Write today for your copy of this complete 52-page Radio Book. _ Write to the house nearest you. Address Dept. 5-R Chicago Kansas City St.Paul Portland, Ore. Fort Worth Montgomery Ward & © = The Oldest Mail Order House is Today the Most Progressive =

Popular Science Monthly 85

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ee NRRL te nearer Pare aa ee ee SPeRREANEE Cr Taner LT ee eee ee 5 —— Ngee He SPR ce ens 8 — og? a : ~ “tee reese sia ee Peer ome ie ee ee tsa moment” menrrenvigrenatraare cts aes OPPO pc BARI athe Oat hl a sa Tee cmb Better Shop Methods Department of Popular Science Monthly So great and so constant is the growth of demand for telephone ser- vice that the Bell System invests throughout the country an average of three-quarters of a million dollars every working day for new telephone plant. New aerial lines are always under construction or extension, new sub- ways are being dug and cables laid, larger building accommodations are under way, more switchboards are in process of building or installation, and added facilities of every descrip- tion being mustered into service to care for the half million or more new subscribers linked to the System every year. This nation-wide construction, this large expenditure of funds, could not be carried out efficiently or eco- nomically by unrelated, independent telephone organizations acting with- out co-operation in different sections “ tet, _ “ 9y> é te he him | ‘ “Ys w J Construction Day by Day of the country. Neither could it be carried out efficiently or economically by any one organization dictating from one place the activities of all. In the Bell System all the associated companies share common manufac- turing and purchasing facilities which save millions of dollars annually. They share scientific discoveries and inventions, engineering achievements,’ and operating benefits which save further millions. But the manage- ment of service in each given terri- tory is in the hands of the company which serves that territory and which knows its needs and conditions. By thus combining the advantages of union and co-operation with the advantages of local initiative and responsibility, the Bell System has provided the nation with the only type of organization which could spend with efficiency and economy, the millions of dollars being invested in telephone service. “ BELL SYSTEM” AMERICAN TELEPHONE AND TELEGRAPH COMPANY AND ASSOCIATED COMPANIES. One Policy, One System, Universal Service, and all directed toward Better Service $25.00 in PRIZES See top of ‘page 4 in front of book for details 49 have averaged *7000 > Per Year for Three Years—Have Made Over $90 PROFIT in One Day’’ That is the statement of Frank DePries, one of our live-wire representatives. Keeton of Mississippi made is first sale. $252 on come with us. $118 in one week. Conant quit a $6,000 job to Vickers of Alabama made ») AGENTS WANTED _ We need more men like these, because the demand for ae Super Fyr-Fyter is growing by leaps and bounds. Sells to garages, sto Ag Bags homes, hotels, auto owners. Approved by the Sederevitens. I are willing to work and amb 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 COMPANY 1714 Fyr-Fyter Bldg., ambitious to some real money, get our i sie. Dayton, Ohio es Square Tester Is Useful Toolroom Checking Fixture By Henry S. Laraby FF eons the cylinder method of check- ing squares is popular with mechanics because the cylinders can be carried around in their toolkits and take up little room, something larger is required in the tool- room for setting squares and testing various precision tools. An excellent form of such a square tester is illustrated. The blades are adjustable and can be reset at any time without much difficulty or expense. Slots for the blade should be carefully finished to the exact size without any play. The tapping also should be carefully done so that the screws are tight and yet can easily be turned with a wrench. The frame can be made of cast iron or machine steel left soft or tool steel pack hardened. In the latter case, the slots can HUSA, PRN CAP SCR \ 10) / —— x @ 6ig 63 NO. 5 TAPER ‘ PIN are —— j! Lh i" ss HH Da a Se oir AMS) Me 1 ae Fad NN - TAPER” it & SNUG ree ' FIT je 2344 SHEET STEEL FRAME -CAST IRON OR MACHINE STEEL TEMPLATE FOR -, SETTING TESTER 6e m ve 2) a 1 i 28 SECTION A-A Eo BLADE - TOOL STEEL PACK HARDENED Details of the square tester and the templet used for setting and checking it be ground out. The plates are tool steel, pack hardened, and ground to fit the slots. The blades should be numbered so that they may be tried in rotation when setting the tool. The method used in setting the square correctly the first time is by means of a sheet metal templet, made as shown, and as perfectly square as possible. Blades 1 and 4 are then set with its aid and the other blades adjusted, working around from blade 1. When blade 4 is again encountered, any noticeable error will be four times the error at blade 1. The templet is then altered and the blade set again until all the angles are exactly 90 degrees, after which the tool is ready for use in testing other squares. The templet should be kept in a box with the square for reference. If the square testing frame is made of tool steel and pack hardened, it will be black in color, and with the brightly polished ground and lapped blade will present a handsome appearance. A hard- wood case with a cover should be made for it. Making an Oilstone Cut Fast AN OILSTONE will cut much more quickly if fine emery powder is ‘“‘worked” into it by rubbing it in the abrasive on a cast iron block. ee er eae ae ee a Better Shop Methods Department of Popular Science Monthiy | See rl FED

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a oolroom of check. mechanics ied around ttle room, the tool- Ng various lare tester adjustable lout much the blade the exact ping also the screws »e turned st iron or teel pack slots can om \PER IN SNUG FIT -CAST IRON HINE STEEL ~ TOOL STEEL HARDENED d the ing it 01 steel, he slots. so that 1 setting > square ins of a wn, and Blades and the nd from intered, mes the nd the fles are he tool ;quares. ox with nade of will be rightly le will \ hard- > made ast juickly into it a cast Popular Science Monthly Measuring Diameters with a Self-Registering Indicator ALIPERS and a scale are used ordina- rily for measuring the diameter of shafts unless a micrometer large enough for the purpose is at hand. The caliper method is slow and the mi- crometer method is useful only for station- 1 oF a \t Mieco “she AA 1-IN. DIAM 2-1N, DIAM. shafts or cylin- Either stationary or revolvi with this gage drical parts can be meas: ary shafts. As a substitute, the tool illus- trated will measure quickly either a revolv- ing or stationary shaft or circular part. A 90-degree V groove is cut at one end of a steel plate and an indicator is pivoted as shown, to bring the head near the center of the notch. The long arm of the indicator registers opposite a scale, which is calibrated by standard plug gages. The contact faces should be hardened.—G. A. Shaper Serves as Punch Press 7° FILL an order for a larger number of small metal parts, in each of which several holes were required, the foreman of a small machine shop rigged up a shaper to serve as a punch press, as illustrated. The die, bolted to the shaper table, car- ries at its back a heavy plate with a dove- SLIDES IN BLOCK How the punch attache ment is set up TOGGLE LEVERS + DOVETAIL--~ tail groove in which the punch block slides. This block is attached to one end of a toggle joint, the center of which is fastened to the shaper ram by means of the sliding arrange- ment shown. As the shaper ram moves forward the toggle causes the punch to descend.—R. H. KAsprr, Philadelphia, Pa. Chair Springs Reduce Fatigue PRINGS attached to the legs of chairs have been found to counteract the fatigue felt by workers in fac- tories where the use of heavy machinery causes a_ certain amount of vibra- tion. Operators who do assem- bling, testing, and similar tasks while seated at a bench, ° find the vibration tiresome and an- noying. These springs reduce fa- tigue effects to a Spvines absorb the a = ration and pre- minimum.—A.'M. vent its tiring effects ee Automatic Drill No. 185 { SS Mr. Punch— Price $2.50 GOOD TOOLS: “Let me bore a hole— then you won't split the wood” says Mr. Punch ‘When you want to put in a screw, don’t start it with a few sharp cracks of a hammer. You're liable to split the wood — especially on delicate work. Let me bore a hole first.” Mr. Punch, the Automatic Drill, is equipped with eight different size drill points, ranging from 1/16 to 11/64 inch. Just pick the size point you want—you’ll find it in the handle —fit the point into the chuck, and Mr. Punch bores the hole. Length, 10 inches; weight 8 ounces. Sold by good hardware stores every- where. If your dealer hasn’t it, write us. Free: Catalog No. 15. Write for it. Illustrates and describes each of the 1500 Good Tools made by Goodell- Pratt. A postcard brings your copy. GOODELL-PRATT COMPANY Tocnith Greenfield, Mass., U.S. A. (eee) ) HOC Cy.4 ust 1500 . | | ee | eee thy Better Shop Methods Department of Popular Science Monthly LE RS FAN TRAE ONIN SPREE 87 EL, CEN 1 ES I IT OLY EOL FS SS ORION |

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86 Better Shop Methods Department of Popular Science Monthiy ' / Unique Bench Grinder. 18 : : . a 19 : . (Continued from page 80) = ; a valuable accessory and, of course, screw | . Hh —— a. plugs will be required. The details of these = 1 Coes Tw : parts are omitted, as little difficulty should 26 i be experienced in making them up ag a 4} necessary. 29 it A 30 ct; How the grinder 31 Bid is used as a lathe 32 i] : ; 33 it} A____af 35 te au ) . it = Hy ae a: a EX x t a 37 \ A Precision Measuring Screw : § 4 2 e e « 39 The first point of superiority of Brown & SHarpe Micrometers , The complete bill of materials for the a | In the accuracy of the measuring screw lies the first point of grinder itself is as follows: 4 oe : ; 4 | superiority of eae Sharpe Micrometer Calipers. ey en : Years of experience in the manufacture of precision tools, com- ; os peers Peonpe bined with special machinery developed in our own plant to meet 5 ed eee es Gee the particular requirements of the work, give the measuring 5 Loose flange, cast iron i screws of Brown & Sharpe Micrometers their superior accuracy. 6 Spindle nut, machine steel. case hardened ot 7 Arbor for small wheel, tool steel ; Ask your dealer to show you a Brown & Sharpe Micrometer, and 8 os ol oe and nut, machine steel, case ing feel the ease and smoothness with which the screw turns. The ep oe closeness of fit between the screw and the nut insures smooth, uni- 10 Spindle driving pulley key, cold rolled steel form action of the screw throughout its entire length. 11 Spindle driving pulley retaining screw, tool steel, hardened Mechanics have recognized the superior accuracy of Brown & 12 Thrust block binding screw, tool steel, Sharpe Micrometers for over 70 years, and rely on their dependa- cag ould veliad ctedt bility and lasting qualities for good work and long service. Retaining screw for dog slide, tool steel, Our No. 28 Small Tool Catalog lists over 400 styles of Brown & —_ re hardened idl s02 Eira ica aie ier area neato 15 Cross slide swivel clamp screw, machine steel A Sharpe Micrometers. 16 — saeeting aneie, machine steel, case Watch for point 2. ne ana aac It will appear soon BROWN & SHARPE MFG. CO. rs — aie } in this magazine Providence, R. I. 0. 6a. Brown & SHARPE TOOLS $ OIL HOLE 26 7K ont] 7 t PIPE TAP REAM - £15 THD. TAP Stromberg-Carlson lt : ae. Radio Head Sets : ax 3 is fe Are balanced as to volume—both ears get the message. This means that the receivers are mated —a feature which permits _the users enjoying the sensation of hearing equally well from both receivers. Stromberg-Carlson Head Sets have three more distinctive features, which you will like:— The receivers are layer wound and layer insulated—to stand up under high plate voltages. The ear caps cover the ears—excluding * outside noises. . The adjustment rod telescopes, therefore 00 on aws it does not catch the ladies’ hair. 4 Order Stromberg-Carlson appa- This book, just off the press, gives al! the ratus through your electrical dealer latest information on saws. Tells how to speed ——— up metal-cutting and get longer and better eimai ae A aiding reg ee in- Stromberg - Carlson f ion on selecting the right saw for ever job. Shows Atkins metal-cutting saws pink Telephone Mfg. Co. machines, and explains their use. Also, con- Rochester, N. Y. tains scores of helpful hints and tables. This book is based on the experience of prac- tical saw makers and users. It is valuable to every man who uses or buys saws for cutting metal. Send for it NOW. E. C. ATKINS & CO., Inc. Dept. D-20 Indianapolis, Ind. Makers of ‘‘Silver-Steel’’ Saws and Tools Sp ee: ays re - CE ASTRA IEEE TRINA Wat eee The main frame, fully dimensioned for con- structing the pattern and machining the casting, and detail of the bronze spindle bushing Better Shop Methods Department of Popular Science Monthly i > Unique Bench Grinder ® -~

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Better Shop Methods Department of Popular Science Monthly 87 _—_—_ der 17 Shim for spindle adjustment, sheet brass : 18 Cross slide swivel, machine steel 19 Cross slide, machine steel ) 20 Cross slide key, machine steel 21 — and — slide, aeenee ta 22 eed screw clamp, machine stee Tse, Screw 23, Feed screw clamp key, machine steel ils of these 24 Slide binders, machine steel, 2 required Ity sh 25 Slide binder handles, bronze, 4 required ity should 26 Feed screw, machine steel mM up ag 27. Feed screw hand wheel, machine steel 28 Cross slide head, machine steel 29 Cross slide head binder, machine steel 30 Motion link, machine steel 31. Motion link roll, tool steel, hardened 32 Motion link roll washer, machine steel 33 Motion link roll nut, machine steel, case hardened 34 Stroke adjusting dog slide, cold rolled steel 35 Stroke adjusting dogs, machine steel, case hardened, 2 required 36 Dog adjusting screws, machine steel, case hardened, 2 required. 37. Motion link shaft, cold rolled steel 38 Operating lever, cast iron, file finish : 39 Operating lever binding screw, machine steel, ‘ case hardened . © s for the 40 T at rest and spindle, cast iron and machine : stee 41 Grinding table, cast iron 42 Grinding table spindle, machine steel 43 Grinding table binding screws, machine steel, . case hardened, 2 required | i “@, 0°. > © = All parts are finished all over except as ’ irdened otherwise noted. ) In Radio These parts are shown in the accompany- | | } | H | | | Steel, case A A ys ° ing details except No. 14, a headless }4-in. G ie een oe i) Construction--- screw, tool ; ‘é ° ° oa a TTT Ch: verate of ne | P The tools you work with are fully as important as aan |p ¥ spindle, table | I your skill in manipulation. For instance, here isa tool steel, elf slide; and at- | PI group of files that all radio builders actually need: hi _™ 1 : : ‘steel, case vie] |! Lf yd ( NICHOLSON 8” Round File. NICHOLSON 10” Haif Round 11; |. . for enlarging holes in panel Bastard File---for smoothing peep i; qe ! boards. _ holes in panel. a NICHOLSON Tungsten Point NICHOLSON 6” Flat Bastard © B. oF File---for surfacing contact points. File---for miscellaneous work. aa a L NICHOLSON 8” Cabinet File--- NICHOLSON 10” Flat File... : |! (S35 J000 for finishing ends and edges of for smoothing panel edges and ee Ee tity be 282" wooden cabinets. beveling. x ] — ove ae = Vt Je Whatever the filing requirement, there’s a NICHOLSON Tot 3 | aay : File for the job. Skilled mechanics and wood workers Ba nee | \|Zs prefer NICHOLSON Files because their sharpness, accu- ri — ig AE racy, uniformity and endurance: assure better results. = Z ; = Y, =i ! 3 4 e's q) % . Be sure the name NICHOLSON is ») egg es 3 fe q stamped on the tang of every file you buv BG =H 1 Bes NICHOLSON FILE G PROVIDENCE. RLUSA. ||) NICHOLSON FILES iE | -a File for Every Purpose a Better Shop Methods Department of Popular Science Monthly — ae J &

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: : ; ' meepeeper asta SRP REGIS ge ta tte eimai. Fr ——— : esti Osh tomer wae any oe gy AS dt iS aati, lsc Ba a tl 2 Be a scenester aaeumchirra aieatched cha eae eke teece E jn vuas ati SL ee ee ee th RR ah Ca See te PL EP ee cee OEE TS Ae pa $e, These SARGENT PLANES ERHAPS it’s a new radio cabi- net nearing completion, or it may be only a bureau drawer that’s been sticking! But whatever it is—if it’s made of wood and needs smoothing or finishing—the Sargent is the plane that will do the job right, in a jiffy. The Auto-Set Bench Plane makes shavings fly. With, against, or across the grain, it cuts the wood without hesitation. It is light, true, keen, time-saving—unsur- passed where the job is difficult. The Sargent Steel Block Plane is particularly good for ’cross grain and end work because of the 50 Water Street Sargent Auto-Set Bench Plane Sargent Steel Pocket lane Sargent Steel Block belong in every workshop low angle arrangement of cutter. It is light, unbreakable, indestruc- tible, and a capable finisher. And lastly comes The Sargent Steel Pocket Plane, so often called “the craftsman’s pet.” And a more practical and useful favorite never existed. It cuts like a veteran, is true as a watch, and in close quar- ‘ters proves its great convenience. ~ Your workshop is incomplete without these tools of the master craftsman. For detailed informa- tion concerning them and other kinds, write for the Sargent Book of Planes and see these models at any good hardware dealer’s. SARGENT & COMPANY Hardware Manufacturers New Haven, Conn. Our big stocks of standard makes of radio sets, parts and supplies enables us to make prompt shipment from stock. Play safe— buy standard equipment from a reliable house. No cut price material. Send $1.25 for Univer nier for close tuning—men- tion size of Condenser or Variometer shaft; $2.00 for 6-phone plug. JULIUS ANDRAE & SONS CO. In iness since 1860 119 Michigan Street Milwaukee, Wis. RADIO YY has been looking o Z this nop for both —=—— gud home use. Operates on A. D.C. current. GUARANTEED one sol Boot Sent anywherein U.S. or Canada Parcel Post prepaid on receipt of money order for $2.2 F ‘ANS Send Fc stamp for ourlist of RADIO ARGAINS a RADIO BARGAINS 17 N.LA SALLE ST.- Fok = $(er-Xere) Better Shop Methods Department of Popular Science Monthly Unique Bench Grinder (Continued from page 87) 20-thd. setscrew; No. 25, 4 binding levers to fit the 5/16-in. slide binders, 24; No. 82, a washer 13/16 in. in diameter, 1{ in. thick, with 4-in. reamed hole; No. 33, a \%-in. 24-thd. hex. nut; No. 36, two 3/16-in. 82- thd. adjusting screws, 34 in. long, with a square head bolt 1 3/16 in. long over all, t bh 1", ie: Sys ee earenisy ~ie # 7 rat | i \ ——_—_.., knurled heads 14 in. in diameter; No. 39° ' x i O BN » Alea) ——i 2 vif eet | NO "kK, iV O: +e U4! el! neat Oy OF |: 6! [Ou |i i : : it | ih How the tool and Finger tables, the table _. motion lever, and other parts are made threaded for 5/16 in. with 44 in. 20 thds. will provide the necessary power. Shop Features for October N IMPROVED toolpost for the lathe will be described by H. L. Wheeler. - In ‘Machine Shop ‘Kinks’ I Have Found Useful,” H. W. Bente will write on mechanical shortcuts of wide utility. Discussing the subject of bab- bitting, Joe V. Romig will give many time-tested tricks in hand- ling anti-friction metals and in casting both large and small bearings. threaded for \% in. with 14 in. 20 thds.; No. 43, 2 square head binding screws It might be added that the bushing on the emery wheel should be .005 larger than the spindle so that the wheel will slide on with- out cramping and the flanges should be tightened just enough to hold the wheel firmly. For best results the wheel should run up to 2500r.p.m. A 4- or %-hp. motor eumueniiaens Ra Aut jllustr The the wi and ¢ run sl used, Dia spec Ther part shor’ axle, shaft driv a shi nect reel sam As s that the may the be ; ano Th

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levers No. 32 _ thick, _\-in, in. 32- +; with No. 39 ver all, 20 THD. F igen a ) thds.; screws thds. ron the nan the n with- uld be . wheel should - motor er for bed nks’ W. ‘ical ~ab- give and- d in mall —_—_—_—____ Better Shop Methods Department of Popular Science Monthly el Auto Differential Acts as Speed Changer in Factory Ho an auto differential is put to in- genious use in an industrial plant is jllustrated in the accompanying diagram. The machine carries two reels of wire, the wire being wound from one to the other, and conditions are such that the wire must run slack at all times. At first a friction cone speed changer was used, but it gave unsatisfactory results. Diagram of a simple method for regulating the speed of one revolving part to suit another Then an auto differential was clamped to a part of the machine in such a way that two short shafts, replacing the halves of the axle, were held in a vertical position. Each shaft carries a sheaved drive pulley. The drive shaft of the differential is replaced by a short shaft carrying a pulley that is con- nected by a belt with the line shaft. Each reel carries an adjustable brake. Both halves of the axle revolve at the same speed as long as the tension is equal. As soon as one side receives a heavier pull, that side revolves slower and the speed of the other side increases. With slight changes, this arrangement may be used on many machines where the speed of one revolving part must be adjusted automatically in relation to another.—R. H. KaAspEr, Philadelphia, Pa. Simplified Lathe Tool Holde O CLAMP- ING screw is needed with a tool holder constructed on the principle of that shown in the accompanying il- lustration. It is made of a piece of machine steel. “SU , ch cee The hole for the \/ Soup stock tool bitisbroached Requires no clamping at an angle of 10 - screw degrees to the long axis. The central opening is then drilled and filed and the saw cuts made as indi- cated. The pressure of the tool post de- presses the tool holder enough to grip the tool bit firmly.—L. M. B. Screwdriver for Tight Places ONE of the most useful tools in my emergency kit is an offset screwdriver with very short bits, made as shown. It was formed from a straight bar of steel about 4 in. square, the ends being drawn thinner. A short portion at each end is turned down at right angles to the shank and one end is turned flatwise. The tips are dressed to screwdriver shape. This device will turn screws wherever there is room for swinging a quarter circle or more at the side.—CHARLES A. PEASE, Monrovia, Calif. Useful in repair work Count Your Gains! A COUNT of what you are getting—from men or machines—is the first step toward getting more. Start out to register gains, and you soon have the gains: Veeder Counters will record them. Here are Production Counters, that tell what your machines produce and ought to produce. Automatically giving you the records which make for improvement—both in developing ma- chines and machine operators into better producers. Hand Talley Counters for counting by the mere pressure of your thumb, anything from packages to people! And Speed Counters for finding revolutions-per-minute of machinery. EVERY needed counting device of the finest manufacture, may be found among eee. COUNTERS This Small Rotary Ratchet Coun- ter (No. 6) counts reciprocating move- ments of the lever, as required for record- ing the output many small machines. When the lever is moved throughan angle of 40 to 60 degrees, the counter regis- ters one. The further 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 regulating the throw of the lever. Price, $2.00. (Cut nearly full size.) Small Revolution Counter of similar model, also $2.00. * Speed Counter Here’s the handiest instrument for finding revolutions-per-minute of a shaft or flywheel. You hold the tip of the counter against end of revolvi shaft; press lightly when the seal hand of your watch comes to O; release pressure when minute is up. A spring clutch controls the recording mechanism. | en | (Cut less than \ size.) The Veeder Speed Counter enables you to keep motors, engines, generators, line shafting and machines operating at efficient speeds. Price, with two rubber tips (as illustrated) $3.50. . ed e The above Revolution Set-Back Counter records the output of any machine where a shaft-revolution indi- cates an operation. Sets back to zero from any figure by turning knob once round. Supplied with from four to ten figure-wheels, as required. Price with four figure-wheels, as illustrated, $10.00 —subject to discount. Cut less than one-half size. Set-Back Rotary Ratchet Counter, to record reciprocating move- ments as on punch presses, $11.50 (list). Hand Tally The Hand Tally illustrated below is used for counting anything from . number of people attending a ball game, to number of packages in an inventory. In the public place it counts persons; in the factory or store it counts stock; in the “open” it may count anything from cattle on a ranch, to poles on a telephone line! Registers one for each pressure of the thumb lever; counts up to 10,000, then repeats. Can be set back to zero from any figure by turning knob once round. Size, exclusive of finger ring, 2 inches greatest diameter. Price, $5.00. Scores of counters not illustrated here await your looking-over in the new Veeder booklet. Costs you nothing to see them—beyond a letter requesting this 80-page book. Let it go in today’s mail. The Veeder Mfg. Co. 44 Sargeant Street, Hariford, Conn.

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90 Home Workshop Department of Popular Science Monthly The Most Useful of My Tools—and Why | VEN as a mother By Joe V. Romig or father will hesi- PLY vt ° SION ALL CS TAMAR wacggpenrrs the ground by means of a stick clamped to raneige ig RD PLE ee LIE ai et LEA ROR. TERS NING | a PHO ey Nt i oa - MLA ATR a August Budde bought this Millers Falls Brace in 1882 He says it’s “good for 40 more years” E old brace shown here has done good work in its time— and lots of it. We refer you to Mr. August Budde, of Paducah, Kentucky, from whose letter we quote: “In. 1882, being then a young carpenter, I needed a brace. I went to a local hardware firm, Geo. O. Hart, and told them I wanted a good one. They sold me a small 6” brace made by the Millers Falls Company. I have used this brace constantly in my work since that time, and am using it now. It is good for forty more years.” Millers Falls tools that have seen years of service—and are good for years more—can be found in every city and town in the United States —and in most foreign countries. If you want a brace or a drill or hack saw that will last a lifetime, look for the name “Millers Falls” on the tools you buy. Every tool so marked is made of fine materials by men who know their business. MILLERS FALLS COMPANY Millers Falls, Mass. Manufacturers of Carpenters’ Tools, Hack Saws and Automobile Tools. MILLERS FALLS TOOLS tate in picking out the favorite child, so will a mechanic hesitate in naming his favorite tool. He loves them all, yet one will be usually of greater practical worth than all the others. My favorite tool is a 50-ft. steel tape line. This I always carry with me in my vest pocket, day and night, weekdays and Sun- days. In a %% by 2%% in. nickel case, it weighs about 5 oz., lies flat in the pocket, is a beauty to look at and a beauty to use. Both for overall length measurements on short or long work, I prefer it to a foot rule as it can be used in cramped places, between shoulders, and through open- ings. I measure diameters, as well as circumferences, and find it more reliable than calipers. Just try taking the measurement of a large diameter by finding the circumference with the tape. The only precaution necessary is to subtract twice the tape’s thickness after dividing the actual measurement by 3.1416. Around my home I find it a most valu- able tool. Here is what I have measured: chicken netting, window screening, rugs and carpets, shades and curtains, cistern chain, wash line, fencing, oilcloth, leather belting, shafting, and lumber. A neighbor one day asked me to lay out his garden in a geometrical design after the style of an old-fashioned flower garden. The center was quickly found with a tape line, and a stick with a nail in the top acted as a pivot for the curves. Flower beds of uniform size and perfectly round are made by looping ‘the eye of the tape line over a nail on a central stick and scribing a line on the tape line at the desired distance. I have known a friend of mine who works on the third floor of an office building to whistle to the tobacconist across the street, order his favorite brand of chewing tobacco, and haul it up with a tape line—to save himself going for it. Another neighbor, who was bothered how to draw some new electric wiring through a conduit, used a tape line and the job was quickly done. Early in the summer I used my tape line on one occasion to lower a cherry bucket from the top of a high tree. This saved many trips tothe ground. While out driving one day with a friend, we were run into by a car driven by a speed maniac who misjudged his half of the road and side- swiped our auto. After the accident he pro- tested that he had been on his side of the road and that it was our fault; that we should have turned out and given him his share. A crowd had gathered in the meantime and we had plenty of witnesses, so I took out my tape line and measured the total width of the road at the side where the acci- dent occurred. Then I laid off one half of the width at several points and drew a line through that. It was then clearly shown that the offender had been at least 6 in. on cur side when he struck us. A sketch was quickly made and all dimensions filled in. Several witnesses signed this, and, when the case came up in court, the jury quickly settled in favor of the tape line evidence that I supplied. Yes, sir, the tape line is my favorite tool. N THE article above, Mr. Romig tells about the most useful of his tools. Mr. Romig has many good rea- sons for the selection of the tape line as the pride of his toolchest. In his letter to the Editor he describes a surprising number of uses for it around his home. But all home workers do not agree. Some prize most highly the saw, others the hammer, others the ax, the plane, the chisel, the file, the screwdriver, and so on. Now then—which is the most useful of your tools» Which one do you use most? Why? And ‘how? Undoubtedly you have some uses for your tools that nobody else has thought of. Tell us about it in a letter of not more than 400 words. | Three Prizes Offered for Letters on “The Most Useful of My Tools” We offer these prizes: $25, first prize; $15, second prize; $5, third prize. The competition closes September 20. The winning letters will appear in the January issue. It doesn’t matter how you write the letter—typewriter, ink, or pen- cil; whether you use one side of the sheet or both; or whether you speak from the standpoint of a pro- fessional or an amateur mechanic. Each letter will be judged by the Board of Editors solely on the prac- tical worth of its argument, and their decision will be final. No letters will be returned unless ac- companied by a self-addressed, stamped envelope. Address Tool Contest Editor, POPULAR SCIENCE MONTHLY, 225 West 39th St., New York. Home Workshop Department of Popular Science Monthly a Sr aa

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Home Workshop Department of Popular Science Monthly 91

Vh Would You Like to Own y This Automobile? y means Guoors running and good looking as mped to this car is, it was about ready for the

Be an Electrical Expert—

e junkman a few months ago. It was that ‘din orks type of “used” car that can be picked up « ' on to for less than $100—sometimes a great deal A e ] ; one i pees. less. If you are of a mechanical turn of i : acco, mind and know how, you often can remodel : “oo such an auto into a thoroughly serviceable Hy eighbor, machine. a re How to do it will be told in-a series of Hi i a articles beginning in the October number of I y in the | : r I used if e line on casion to i a cherry if from the Ky a high HY This i | many i to the if ile out | one day How the home worker can remodel a car, ty . friend as this one was rebuilt, will be told in a ik ? remarkable series beginning next month ty ere run a niac who , : H | nd side- POPULAR SCIENCE MONTHLY. This series | t he pro- was especially written for the Home Work- i le of the shop by Ray F. Kuns, Principal of the Ha that we Automotive Trade School, Cincinnati, : him be Ohio, who rebuilt the car illustrated. ©A481023 HS Mr. Kuns will tell what to look for in | 1eantime purchasing a used car, how to dismantle it, SP Bie: Electrical Rs . oT took | | how to overhaul the frame, the spring iniecouse” he Best Electrical Home- the total assemblies, front axle, steering gear, rear CC. Adams, B.S. neral ie ole axle, universal, brakes, and transmission; Electric Compa. - St udy Course 7 hat e half of how to dismantle, inspect, and repair the Merten Areadt, E. Ee ectrical ew a line engine and electrical equipment; how to Tat. oney an Buy y shown rebuild the units into the car frame, make ‘Pecteaper of Sheckdesl Engineer. yo i : fered tn on body and top repairs, paint the auto, and if Ensinessi 2, Dartmouth College This is the most practical Electrical course ever offered. : run in the engine Winfield Dexter Bearee,B.S.,£.£. Over 20 world famous engineers—note their names and etch was F Statieticlen— Railway and Traction positions—have prepared our special instruction papers. filled in. Electric Company. This practical training course will help the ambitious man { P J. Bushnell . vehi Blueprints to Aid You in ” patent alth Edison = dalari 33, 200 $3 papost Y. r quic y men omm 'nwe: son alaries to a ear ° pany, Chicago. t th d t at all | in the electrical field. M skin: bent nit rta SGGunA! ainterprmtaranen pecaats te . N PLANNING your fall work, do bed eg pag ne ae ae with Leer electrical training—can earn. That is just the kind of tra‘ning rite tool. not overlook POPULAR SCIENCE Louis Derr, S. B., A. M. we are equipped to give you. MONTHLY’S invaluable blueprints, Professot of Phiysice, Massacho- Be an Electrical Expert se titut ° a. . The El 1 Expert is the B}G PAY MAN. All Electrical li bi ————7 any one of which can be obtained for Wilion Esty, S. Ba, M. A Electrical and ak other trade oF profesion offers as man chances for quick advance: An 25 cents by using the coupon below. Engineering, Lehigh University. ment. Do YOU want to be in the BIG PAY CLAS SS? Here is your chentees W. 4. Freedman, C. 8.8, & ioaiondonae,: We can make you a Certified Electrical : : Department of * Electrical ost Blueprint Service Dept. Bngis‘ing, University of Vermont’ §=—»- Qwm Your Own Business—Earn While You Learn Popular Science Monthly H. 8. Gow, A. Disibitin Com ; A ea weeks ry you sons yas cum nash good money ott the side by doing a in jo tartt n 225 West 39th St., New York ——- eg clscestenl sepelr sat thatetatien tebe, Tune Sys you a fine start towards am GENTLEMEN e Ward arrison, ° just how to do it when you are ready. ba uminating’ Engineer, General first Send me the blueprint, or blueprints, et to Satisfaction or Money Bock $5, —— checked below, for which I in- Flectrical Enginee?, The? Cater ‘ad ane RC TRICAL SAY we can m we ‘ e . “9 » te rae wi COMO) 3 a:< cents in stamps or coin: waukee. ANTEE it. YOu gre not sbeckutely ; No. a THe — “ Robert a Lary Ph.D. Se. DB. Practical Hlectsical Course, we will refund ‘tters So. BS ener ar Cc Fota tnaten e Laborat 7 ng de tome every cent you paid us 2. Smoking Cabinet,.... ....... 2c O Pras, of thn ieverd of Bangreek: Free Electrical Outfit i . oe Table... . ‘i - John Mills, A. M. r We give absolutely free a real Electrical write % : are 9 alse Savoie ¢ Engi Ameri hone an Outfit—containing a high-grade motor, 6. V. T. Radio Receiving Set..... asc “{] Telegraph Company. tos bridge, electrical st, etc. pen- 8. Shaving Cabinet............. ae O David Penn Moreton, E. E. It is not @ plaything. but a practical ex- 9. Arbor with Gate and Seats..... 25e¢ O Associate Professor of wocions nai hypo outfit, "that would cost you : the 10. Porch Swing ................ ae O Brelocering, Armour Institute « American School 0.00 retail. you 11. Bench and Tilt: Top Table. .... ec O Arthur N. Nelson The American School is | Make Money by Joining 12. Electric Washing Machine..... 25c ~~ . Superintendent, Interior Wiring not a money-making cor- the Big Pay Class | pro- ke A eee 2c O Department, Commonwealth Edi- poration, but like resident © Dig v ° 14. Toy Train, Horse, and House. .25¢ O son Company, Chicago. schools and colleges, = You wish yo were init now. You can be anic 15. Home Workshop Bench 2c O Henry H. Norris, M. E. chartered strictly as init a yearfrom now. Send in the coupon i , 5 : egg Sia Formerly Professor of Electrical ‘*Educational ‘Institution, for full information and get our free 7 the 16. Inlaid Radio Cabinet Caer dons 25c¢ a) ay | re University. not for profit.’ 300- page B ulletin. 17. Cedar and Mahogany Chest...25c 0 Dana Pierce, B : More than 200 famous American School - - £Ciepnone iabdie and otooil..... e rs ms ucators # = spent iS Getinkeas Gack ase Piscreaibocineer, Under tare’ | CRgincere ad esata | Dept. E675, Drexel Ave. & 58th St., Chicago and ae se O ro, struction papers for our So oS eee c E. W. Seeger, M. E. ae AMERICAN SCHOOL. Chicago No ; 21. Colonial Writing Desk........ 25e¢ O Electrica I Engineer, ba! Cutler- For overa quarter of a | Dept. E-675, Drexel Ave. & 58th St. ’ 22. Girl’s Cabinet and Desk....... aoe AJ + ncn century, Big | Engineers, J 4 f of your 300 page bulletin S ac- : 23. Pergola Garage.............. 25¢ O eg 4 Educators and Business | 50 jolow ie ieee opportunity for me ‘ ee GO OSE —E ee eee ce O George E. : E. Shaad, E. E. Men have recommended eclectricity. Thi t puts me under ’ sas of ical Engineer- the American School. The in Electricity. is request p ssed, | 5 Lem Pe ogd a a Beets = s ig —— of Kansas. know that our long experi- | ° obligation. . Baby’s Crib an ay Pen..... ic 8 E., M. S. ed nal -in- i : Mislecateal sal enatncn, Western stitution guarantees better Ree eco. crave chakueccunues. agaiamis } jectric WY t GMs iin 5 oi PEs 6s OAH 4s + EL o READ bid a vee A. G. Turnbull can be given —“ any eclinatcn ademnh,.. Lo. te. ak icisscvateccctascce tieoos : Departme’ or ro : r is sd Edison Company," ma ane MMU Soce cvcnaspenses ao obs ebbersy State . 3 SOOM Es eos UE dob Lee ose Te RRR OR See Cie BRE SION anes 6 5 vin cia ctecnenadtines wee CE ad j 7 Home Workshop Department of Popular Science Monthly 93 | A marvelous new fuel — eS oe) ee eee er ee ee | yy”. —~ ; fi

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Page 76

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4 7 This lever controls Automatic Feed. Frié- tion Feed runs drill rapidly down to work. Then you shift lever to horizon- tal and Ratchet Feed takes hold, keeping pressure steady and uniform. Gear Shifter YAnt if “Y ANKEE” Bench Drill Nurses small drills Small size drills can be safely used in tough material with the “Yankee”’ Bench Drill. Automatic Friction and Ratchet Feed takes the place of human skill. You can’t overfeed. Just turn the crank. Friction Feed runs drill rapidly down to contact. Time saved. Then Ratchet Feed takes hold and gives absolutely even pressure. Drills saved. No. 1005 (illustrated) Two speeds; 3-jaw chuck holds drills up to 4 in. Entire length, 28 in. No. 1003 Single speed; 3-jaw chuck holds drills 183 j in. up to 34 in. Entire length “YANKEE” VISE No. 990 For use on bench drills and other machines. Machined true on all sides. Swivel jaw. Jaws 2 % in. wide, 1 % in. deep.

Dealers everywhere sell ‘‘YANKEE’* Tools Write for Free Book Tells all about “Yankee” Ratchet Hand and Breast Drills, Ratchet Screw- drivers, Ratchet Chain Drills—and all the inge- nious “Yankee” Tools.

NORTH BROS. MFG. CO., Philadelphia, U.S.A. “YANKEE” TOOLS i. ememmmuaeal Home Workshop Department of Popular Science Monthly

Building a Supersensitive Radio Set (Continued from page 76) be used; a 30-ohm rheostat is necessary. A 22'%-volt B battery can be used for the plate circuit but better results will be ob- tained with the use of a battery of from 45 to 90 volts. Both the upper and lower sections of the stator should be wound clockwise. The upper terminal of the upper section (1, in the wiring diagram) connects to the resis- tance R1 across the condenser bank and to the phone terminal 3, while the lower end, 7, of this winding connects to one of the leads from the rotor. This connection is very important, since, if the connections are re- versed, the set will not work at its full efficiency. The other end of the rotor wind- ing connects to the plate terminal of the tube socket. One terminal of the condenser bank re- sistance, Rl, connects to the ground ter- minal and the other to the tickler coil wind- ing, 1. The stationary plates of the condenser, 2, connect to one terminal of grid leak, R2, and also to the aerial post. This terminal of the grid leak is then connected to the upper terminal of the bottom stator section, and from there a wire runs to one terminal of the grid condenser. The other terminal of R2 is connected to the other terminal of the grid condenser and from that point a wire goes to the grid terminal of the tube. Binding post 3 serves for one terminal of the telephones and 4 of the other. Post 4 also serves as the positive terminal of the B battery. Post 5 is the connection for the negative of the B battery and the positive of the A battery; 6 serves for the negative ter- minal of A battery. The panel used was 7x10. Operates a Loudspeaker This set is very sensitive and can be used with ‘any small type of aerial. In some cases, for the reception of local signals, it can be used without an aerial at all. It should never be forgotten, however, that when using any type of set, the results ob- tained are usually in proportion to the efficiency of the aerial. With'an aerial 60 ft. long, local stations were brought in by this set loudly enough to operate an ordi- nary loudspeaker so that speech could be clearly understood over.a fair sized room. It is important in wiring the set to make sure that no long leads are used. While short, direct leads, crossing and crisscross- ing, do not look as well as long ones running parallel to each other, they give better results and greater freedom from noises caused by the inductive feedback between different parts of the circuit. Bus bar wiring, either bare or covered with “spaghetti” tubing can be used, but for all general purposes, No. 18 annun- ciator or bell wire, which is cheap and easy to work with, will give good results. If the set is used with an ordinary aerial, the tuning is not very critical and is done by varying the wave-length adjustments and regulating the regeneration. When these adjustments have been made, further adjustments of the values of the grid leak resistance and the other resistance across the condenser bank will help bring the sig- nals to full intensity. If the set is used with a loop aerial, one end of the loop should be connected to the : aerial post and the other end connected to the ground post. Another method is to con- nect one end of the loop to the aerial and a ' regular ground to the ground post. When used without an aerial, the ground wire should be connected to the aerial post. Where these comparatively inefficient types of aerials are used, the set becomes very critical in tuning and great care and patience are required to get good results. In such cases a distinct whistle, which varies in pitch and intensity as the adjustments are made, will be heard in the receivers. This is a characteristic whistle present in super- regenerative receivers. If the tone of the whistle is low and prom- inent, it can be decreased in strength and increased in pitch by increasing the resis- tance of the resistance elements. If it is too high, it can be lowered by decreasing the resistance. When the set is properly ‘ad- justed a high pitch whistle is present but it is not very noticeable and does not interfere seriously with reception.

Picture Frames Easily Nailed in Machinist’s Vise HE simplest fixture for making picture frames is an ordinary machinist’s vise. After the molding for the frame has been cut in a miter box to the right lengths, one piece is placed in the vise, as shown. The front jaw fits into the glass rabbet and one corner of the jaw is placed exactly flush with the end of the rabbet. The outside edge of the molding is protected with a strip of cardboard or wood from being damaged by the other jaw of the vise. The piece to be nailed is held against the mitered edge of the molding in the vise with

}.MOLDING IN VISE y CARDBOARD TO —__ PROTEC T MOLDING VIEW LOOKING DOWN

—

MOLDING TOK. * BE NAILED | SS

ii “NOTE THAT VISE JAW qi 1S FLUSH WITH END OF RASBET | AND SERVES ASA STOP WHEN SECOND PIECE IS NAILED UP TIGHT How picture molding is held in a machinist’s vise for gluing and nailing a frame together

the sharp corner projecting back a trifle, as indicated by the dotted lines in the small diagram. This is because nailing tends to draw in the joint. Holes for the nails are. then drilled through one piece and a short distance into the other with an automatic hand drill or other tool. Both mitered edges are thinly covered with hot cabinetmaker’s glue,and the joint is nailed. It is automatically lined up | because the front jaw of the vise acts as a stop. When two pieces are joined, the other pair are put together, and then both pairs are nailed in precisely the same way. Care should be taken not to use too much glue, and if any accidentally gets on the face of the molding, it should be removed imme- diately with warm water. This little trick of using a machinist’s vise is invaluable when frames have to be made in the home workshop.—A. L. C.

Home Workshop Department of Popular Science Monthly

Page 77

when you want a_ cool - ; kitchen. —-} 2 Cents to Cook a Meal ih Even if Oxo-Gas did cost more than coal, it Maosgok your furnace an_ still pay to use it instear Fo eow e enn Save’ of coal. With Oxo-Gas you work and coal money, have heat when wanted enjoy .greater comfort and as long as wanted.

Let your coal range be an Oxo-Gas Cook as with city gas. purpose, with no_ coal> scuttle drudgery and no smoke, soot or ashes. But as a matter of fact, in- stead of costing as-much, Oxo- Gas is so cheap as tobe practically incomparable with the cost of coal. Just think—one gallon of kerosene will’ make enough Oxo- Gas to heat a range or heating stove eight to ten hours. The average cost of kerosene being from 8 to 12. cents a gallon, the cost of cooking. or heating with Oxo-Gas is but 1% to 2 cents an hour. 2 cents worth of gas to cook a meal. Write for Free Book S<‘entists who have experimented with. it, house- keepers who have tried it, declare Oxo-Gas to be one of the greatest things ever accomplished for mankind, Wherever this remarkable gas is introduced it creates a sensation. Already more than one hundred thou- sand homes throughout the country are now using this new marvel-fuel. You owe it to yourself to learn allaboutit! . Write today for our free book on Oxo-Gas,

Agents Wanted! Gives you all the facts— tells you how Oxo-Gas is made, how used in any coal range, heater or furnace; what it costs, etc. Besides cook stoves, heating stoves and fur- naces, Oxo-Gas_ appli- ances may be had for Hot Water Reservoirs, Garages, Camps, Yachts, Shipmates, Water Stills, Some choice territory for Oxo-Gas agencies and dis- tributorships still open to thoroughly _ responsible parties. Your own localit may yet unassigned. 4 you can qualify. we offer you «1 genuine < unity to make $10, a year and more, Just write and ask us for our agent's proposition and we will discuss the matter with you either by mail or in person.

Hot Water Coils, Pressing Machines, Revolving Bake Ovens. Indicate on the coupon the particular use for Oxo-Gas you're interested in and we will send you full information, postpaid and free, with no obligation. Clip and mail coupon now. GLORIA LIGHT CO. 103-113 N. May St. CHICAGO Branches in 40 American and Foreign Cities = ——K—H_ es ewe ee ee ee oe THE GLORIA LIGHT CO., | : 104 103-113 North May St., Chicago, Illinois. GESTLEMEN: Please send me free book on Oxo-Gas, the new-day fuel for cooking and heating. (Check particular appliance you're interested in.) ‘0 Cook Stove 0 Garages

oOxoO- GAS O Hot Water Coils and Heaters 0 Camps O Pressing O Furnaces 0 Yachts Machines O Shipmates 0 Revolving Reservoirs O Water Stills Bake Ovens Serer eee eee eee ee ee ee | | I t | | i] ' © Hot Water 2 | ! L] t i] t Home Workshop Department of Popular Science Monthly 95

Page 78

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Home Workshop Department of Popular Science —— “Red Devil’ ise mg, ha cleayvance and bore uith or against the grain of any wood. Style 2400—10 [16 in. shown re, the Gaff! HEY give you a power- ful grip at just the right place—a non-slip hold on that rusty nut, that screw- eye you want to turn, that rod you want to loosen, that wire you want to cut. “Red Devil” Pliers give long time service and satis- faction—drop forged of steel —will last for years. Made in 100 styles—one for every purpose. “Red Devil’’ Slip Joint Plier shown above, the most use- ful tool of its kind for the home, workshop or car. The handles fit the hand with- out pinching—the thin nose reaches hard-to-get-at places —the slip joint widens the range of objects that can be gripped. “Red Devil’? No. 1024—61% in. —at all good hardware dealers, or if not in stock, send $1.00 and dealer’s name for a sample tool. The ‘‘Red Devil” Me- chanics’ Tool Booklet is a handy reference guide for users of good tools— send for it—it’s free. SMITH & HEMENWAY CO., Inc. Manufacturers of “Red Devil’’ Tools 264 Broadway New York, N. Y. “Red Devil” Glass Cutters—the glaziers’ Standard tools

How I Built a Small Garage (Continued from page 93) a tedious way to do it, but we obtained good results. To put on the siding and shingles was an easy job. If possible, a builder of a similar garage should buy siding in lengths to fit without unnecessary sawing, but I was un- able to get the right lengths. The doors were of the simplest variety or “made in,” that is, siding in 8-ft. lengths was nailed to the door frames, just as if the opening were.to be closed permanently. The doors were then completed by sawing through the middle of the siding and swing- ing each half on hinges. When the garage is painted it will be quite presentable, and as useful as a much more expensive one.

Unique Portable Aerial VERY owner of a portable radio set would appreciate an aerial that winds up without kinking into a space no larger than a pocket steel tape. To make such an aerial is not difficult. Obtain 100 ft: or more of copper ribbon about 14 in. wide from a dealer in brass and copper or any large electrical supply house. Then get a pocket tape line holding 100 ft. of cotton tape; an old or secondhand one will do. Pull the tape out and cut it off abopt 6 in. from the very end. Fasten one end of the copper ribbon to this short length of tape line with two small paper fasteners. COPPER RIBBON

TAPE MEASURE A cheap cotton tape measure is converted into a reel for 100 ft. of aerial ribbon Then reel up the aerial and fasten the small ring from the end of the tape line onto the end of the ribbon. Two small insulators and some cord are also necessary. Then, when you wish to put up the aerial, tie an insulator to the end of the ribbon and fasten it to a tree or post. Unreel the aerial, fasten the other insulator to the crank and tie it to any handy sup- port. For a lead-in use a simple lampcord with a battery clip soldered at each end. —JOHN A. MAHON.

Oilcan Serves as Automatic Reservoir for Poultry Pen A FIVE-GALLON oilcan that does not leak may be used as a reservoir for the drinking water pan in poultry yards or hen-houses. A hole is punched in the screw cap and the can is filled with water. It is then turned up- side down and placed on «& / wooden block f in such a way that the cap is over the drink- ing pan and a trifle below the top of the pan. When the pan is filled to the level of the cap, the water in it prevents air from entering the reser- voir and stops the flow of water. As the pan is emptied, more air enters and in this

| way the pan is automatically kept filled as long as there is water in the reservoir.— E. R. SmitH, Walla Walla, Wash.

You Are Welcome Everywhere

Everyone should possess the ability to play some musical instrument. It will greatly increase your popularity and personal satisfaction. You are wel- : come everywhere with a sweet-toned ~ BOESCHE: Saxophone It is the one instrument anyone can learn to play— easiest of all musical instruments to master. With the aid of the first 3 lessons, which are sent without charge, the scale can be mastered in an hour; ina few weeks you can be playing popular music. A Wonderful Entertainer The Saxophone is the most popular instrument, for nag entertainment, church, lodge or school. You oy weeny add to your income if you aomze. xophone players are always in demand for dance orchestras, EE Trial—EASY Payments You may try any Buescher Saxophone, Cornet, Trumpet or Trombone or other Band or Orchestral Instrument six days in your own home without obli- goto. y perros —z = Ti. for A = none pepmente, en or free axoph: 10) ° = tioning instrument in which you are nee (89) BUESCHER BAND INSTRUMENT co. Makers of ee hae de in Band and Orchestra Instruments 3189 Buescher Block Elkhart, Indiana

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Page 79

here ly some se your tinted ashen, elope: cilities ror, l send U.S. isfied. co. ian: “RY nd sold. ladeiphia Home Workshop Department of Popular Science Monthly 95 Reinforcing an Open Wrench with a Clamp HEN it is necessary to use an open end wrench for unusually heavy work, the jaws can be protected from spreading and possibly breaking by means of a steel clamp placed across them, as shown. This was done recently in the case ofatankcapthat. had become cor- roded and was exceptionally hard to remove. It was necessary to use a long pipe extension to ob- tain sufficient leverage to turn the wrench, but no harm was done to the wrench jaws because of the reinforcing effect of the clamp.—M. P. V. 4 WRENCH-°"" A clamp strengthens the wrench jaws High Jumping Standards T= uprights, A, of these high jumping or vaulting standards are straight pieces of 1 by 3 in. lumber. For jumping standards the height is usually 6 or 7 ft.; for vaulting, about 13 ft. The supports, B, also 1 by 3 in., are nailed to the uprights and braced by the pieces C. Brads 1% in. long are driven into one edge of each up- right at intervals of 1 in., as indi- eated, and are allowed to pro- ject 4 in. to sup- port the cross bar support, D. This is made of heavy wire, bent as in- dicated to sup- port the 1-in. square cross bar. To raise or . lower the wire \wnr supports, they \ a are simply lifted The jumping bar is quickly UD and pushed raised or lowere back until the wire loop clears the end of the brads sufficiently to move freely.—HuGH CARD, Lexington, Ky. Broom Hanger Made from a Wire Ceiling Hook EEDING a broomhanger not long ago, I tried in several stores to buy one, but without any luck. I found, however, that it would be a simple matter to make a substitute from an ordinary wire ceiling hook such as is to be found in almost any clothes closet. By bending this as shown, I made a broom hanger that is doing the work as well as any that could be bought in the _ stores. —W. W. PARKER, Lead, S. D. A Slow Setting Plaster OME workers sometimes will find useful the painters’ and plasterers’ trick of mixing dry plaster of Paris with vinegar instead of water to make it retain its workable qualities for a longer time. It is then similar to putty and does not set so quickly.—M. C. E. Ten Days Bring surprises when you combat the film Make this test Here is a test which will be a reve- lation to you. It has brought to millions the glistening teeth you see everywhere today. Ask for it and watch the results. They will amaze and delight you. Why teeth discolor That viscous film you feel on teeth is what hides their luster. Much of it clings and stays. Soon it becomes discolored, then it forms dingy coats which brushing does not effectively remove. Film also holds food substance which ferments and forms acid. It holds the acid in contact with the teeth to cause decay. Germs breed by millions in it. They, with tartar, are the chief cause of pyorrhea. Few escape these film-caused troubles under old-way methods. Dental science has found two ways to effectively fight that film. One acts to disintegrate the film at all stages of formation. One removes it without harmful scouring. After many tests, these methods were embodied in a new-type tooth paste. The name is Pepsodent. Now careful people of some 50 na- Avoid Harmful Grit Pepsodent curdles the film and removes it without harmfuPscouring. Its polishing agent is far softer than enamel. Never use a film combatant which contains harsh ¢grit. Pepsadent REG. U.S. The New-Day Dentifrice Now advised by leading dentists the world over siesta Save Your Tools and Save Money! A place for ever Tool aed = H. Gerstner & Sons 345 Columbia St., Dayton, Ohio tions employ it daily, largely by dental advice. Watch the results Some results are quickly seen and felt. No one can doubt their bene- fits. But Pepsodent also multiplies the alkalinity of the saliva and multiplies its starch digestant. Those are Nature’s agents for fighting acid and starch deposits on the teeth. Every use of Pepsodent gives them mani- fold effect. That is why Pepsodent is in world- wide use. Those who once see and feel its results will never go with- out it. Make this ten-day test. Note how clean the teeth feel after using. Mark the absence of the viscous film. See how teeth become whiter as the cloudy coats disappear. This is vastly important to you and your family. Cut out coupon now. 10-Day Tube Free THE PEPSODENT COMPANY, Dept. 209, 1104 S. Wabash Ave., Chicago, II. Mail 10-day tube of Pepsodent to ee ee ee ee ee ewceeeedeseeeseessusesodeocoowued Seeueanye se ece ONLY ONE TUBE TO A FAMILY OLD PIPE BENDERS Standard of the World HAND and MOTOR OPERATED 14 Sizes of M: wae} Gem © bed ce ow way. Per bend. : sage. Fr Sie insrate $7 igs $5 cent S ae 8 pine $1:00" Send for Catalogue. a AMERICAN PIPE BENDING MACHINE CO. S1 Peari St. One year to pay. Boston, Mass. ere mort nna ever published. TWENTIETH CENTURY Recipes, Formulas and Processes This book of 800 pages is the most complete Book of Recipes Hints, Helps, Practical Ideas and Secret Proc- esses covering every branch of the useful arts are given. Popular Science Monthly, 225 W. 39th St., New York Book of A mine of information, up-to- date in every respect. Con- tains an immense number of formulas that every one ought to have ‘that are not found in any other work. Price, $4.00 Popular Science Monthly

Page 80

Seeneae TT ° eS PU CE ae Rieti settee hts rsh BULLDOG Pipeless Furnace Puts the Bulldog Pipeless Heater in Your Home Then Only $10 a Month! If you are even thinking of a furnace, write for our free catalog. The Bulldog is one furnace you MUST investigate. true pipeless furnace. Comes completely erected, A really extra develop- ment in heating. A distinct forward step. Factory connections in both East and West. We ship from nearest point. Do not neg- lect to write for our catalog now before you forget. Two Hours to Install Any man knowing how to use a hammer ind saw can make the installation in this time. ular shape (one of the com- mon sense principles) allows through any door. The man desiring a warm, cheerful home at the very minimum os ane een and fuelexpensecannot afford consider the purchase of any furnace until he finds out about the Bulldog. So write. Fits Any Floor Height depth t or cellar may be — the Bulldog fits it. The feature) takes care of this. When you read this alone Should be stant ts ealachss sufficien: a to choose the Bulldog. Pee write today for our offer and our catalog. Mail this coupon, one jessauscesssaccees Babson Bros. eesesenesccencscs: 19th and California Sts.. Dept. 13-66 Chicago Withest eblicating » “7 if any way, please send me Dow catalog down offer on the Bull TB cecctacdvetssease SOCCES COREE COCSCCCCECESeECeES Popular Science Monthly Address.........0. onal The Science of Fire Fighting (Continued from page 37) Street, New York, an excellent fireproof building, caught fire from an explosion of potassium stored there. One incident of the extinguishing of this fire was unique in the experience of the oldest fireman present. After a tremendous quantity of water had been poured into the building, its great walls began to bulge like a giant football under the pressure of an air pump. There seemed no explanation of this phenomenon, for there had been no explosion after the one that started the fire, and the firemen were certain the walls were not collapsing because their supports had been burned away. At last the walls cracked, hurling great chunks of masonry and a huge flood of water into the streets. Scientific investigation brought the ex- planation of this weird happening. The bulging and bursting of the walls was caused by the swelling of great rolls of news- print paper as they absorbed the water. Ammonia Fumes Are Dangerous A most dangerous fire from a fireman’s standpoint is one occurring in a large meat market or a large restaurant where am- monia is employed in the refrigerating ap- paratus. In the past, many firemen have been overcome and some haye died from ammonia fumes when fighting fires of this kind. Science, however, has furnished them with protection. It has perfected the gas mask, and it has brought about laws compelling persons using ammonia for refrigeration to equip the freezing apparatus with pipes which, in case of fire, carry the deadly fumes beyond the roof of the burn- ing building. Nitric acid, employed in a great number of industries, also gives off fumes under heat which may cause death when inhaled. This is even more dangerous than am- monia, because it is odorless and conse- quently cannot be detected by the fire- fighter before he has absorbed enough of it to cause unconsciousness. Chlorine gas, which the fireman frequently encounters in fires in bleaching establishments, is like- wise poisonous. Chlorate of potash, com- monly used for sore throats, becomes highly dangerous under heat, for it will ex- plode and also give forth a poisonous gas. Some chemicals present serious problems for the fire-fighter because when they burn they cannot be extinguished by water. Un- slaked lime, for example, burns all the more fiercely under a light spray of water, but may be extinguished by being completely drenched. Yellow phosphorus Ifas a similar action under water. In oil fires water is quite useless, only causing the fire to spread, since the burning oil rises to the top of the water and floats away. Fires of this sort must be smothered by sand, flour, earth, or some similar material. Substances which foam readily, such as a certain residue of licorice manufacture also have been used to smother oil fires. The destruction of the city of Smyrna by fire a few months ago offers a striking con- trast between the inefficient fire-fighting methods of the past and present day scientific fire protection in the United States. A photograph of one of the engines used in attempting to cope with the Smyrna conflagration is shown on page 36. The photograph gives a vivid explanation of why Smyrna was reduced to ruins. Yet it was not so many, years.ago that apparatus almost as crude was used by the firemen of the greatest cities in America. There are plenty of people who recall the picturesque days of the volunteer departments, with their ‘“‘manuals’’—hand drawn engines— hand pumps, red shirts, trumpets and one- section ladders. In those days, and even later, it was the custom to close all doors and windows in a burning building, the theory being that the fire would be cut off from oxygen and would burn itself out. No fault can be found with that theory, but the trouble is that it is im- possible to seal a building hermetically. There always will be leakage of air sufficient to feed the fire when the building is closed. A more serious objection is that a closed building offers no escape for smoke, and consequently makes it impossible for fire- men to enter to fight the fire. The present-day method, especially when a fire has started in the lower part of 2 building, is to open the roof and also to make an opening at the bottom. This forms a sort of chimney, which, while it causes the fire to burn more fiercely for a time, also permits the firemen to get at it and put it out. In the Fire College in New York City we have two miniature buildings in which we demonstrate this principle. All modern theaters now have roof scuttles above the stage which open automatically. In the Williamsburg section of Brooklyn, where rows of old fashioned wooden tene- ment houses are common, this method of clearing the atmosphere within a burning building has been employed recently. Pre- viously several of these rows had been destroyed, chiefly because they all. had con- cealed attics extending the whole length of a row, through which the fire spread in- visibly after it seemed to be under control. Then firemen in that part of the city, started to fight these fires by opening up the roofs and ground floors at three places— at the ends and at the places where the fires had started. The modern fire-fighter is ever resource- ful and ever ready to expose himself to any danger, if there is a chance of saving lives. Firemen Trained in College The New York Fire Department operates a Fire College which is a college in faet as well as in name. Scientific fire-fighting from every aspect is taught by officers of the department and by professors from the scientific departments of leading colleges and universities. Among the subjects taught are general fire fighting, use of ap- paratus and tools, engines and boilers, high pressure systems, marine fires, high tension electric currents, combustibles and explo- sives, gasoline and motors, fire alarm tele- graph, auxiliary fire apparatus, first aid to the injured, discipline and administration. By theoretical study of thesesubjects and practical drills the department is grounded in the scientific principles of modern fire fighting. Likewise in equipment the mod- ern fireman utilizes the latest scientific dis- coveries. Water towers that permit a hose line to be raised 10 stories above the street, efficient alarm systems, and motor-driven apparatus—these are only a few of the aids which science has given the fireman. But, although he utilizes the latest scientific equipment, the professional fire- man prefers to prevent fires rather than to . extinguish them. —A 8 roqdgnmn —_—iew SS ek hee” pow Le nee Popular Science Monthly

Page 81

a of are que vith yne- the ina the uld vith im- lly. ient sed. sed and fire- hen of a » to rms uses me, put ork s in All tles ally. lyn, ene- 1 of ring Pre- een con- h of in- trol. ‘ity, the aS fires rce- any ves. ates faet ting s of the eges ects high sion plo- tele- d to tion. sand nded - fire nod- : dis- hose reet, ‘iven aids atest fire- an. to Will the Sun Ever Fail Us? (Continued from page 41) has revealed that virtually every chemical element known on earth is present in the sun. In fact, some elements have been dis- covered in the sun before it was possible to isolate them on earth. A striking example of this is helium, which was observed in the sun 30 years before its presence on earth was known. Coronium, a gas which occurs in the corona of the sun, has not yet been found on earth. In the brilliant photosphere are observed dark areas known as sunspots. What they are, no one knows. They have been de- scribed variously as cavities in the sun’s surface and as giant whirlpools. From them arise great whirling streams of glow- ing gases and around their edges circle tongues of flame. The-number of sunspots varies, but varies definitely. A period of about 11 years covers the development of the number from a minimum to a maxi- mum and the diminution to a minimum again. To astronomers this carries an im- portant message—since the spots are peri- odie in appearance they must necessarily have some deep-seated connection with the fundamental facts of the sun’s structure and activities. The study of sunspots also has shown the astronomer that all parts of the sun’s surface do not appear to rotate at the same speed, from which fact he has drawn his conclusion that the center of the sun cannot bea solid body. Sunspots Produce Storms on Earth Just at present the daily photographs made from the U. S. Naval Observatory, show that the sun is passing through what astronomers. call the minimum sunspot period—a matter of vast interest to the earth, since sunspots have been shown to produce, in a mysterious way, magnetic storms that cause great havoc on the earth. Recently Father Ricard, director of the astronomical and mathematical depart- ment of the University of Santa Clara, Santa Clara, Calif., declared that electrical waves emanating from sunspots were re- sponsible for all storms on the earth and the other planets. These waves, he said, break up cloud formations in the atmos- pheres of the planets, causing precipitation of the moisture they contain in the form of rain. Astronomical instruments show enor- mous flames of red glowing gases shooting outward from the sun’s surface for thou- sands of miles. Is this fire? Astronomers say no, not in the sense, anyway, in which we know fire on earth. Fire to us implies combustion, burning; and scientists say the sun is not burning. There is no sign of any wasting or diminishing in the sun’s composition. Instead, after supplying light and heat to its universe for probakly millions of years, the sun is going on «s ever before, and has even increased its power, some astronomers say, since the beginning. Even should the lessening in the sun’s energy noted by Dr. Abbot continue at a regular rate, scientists say that it would take centuries and centuries before the sun would cool off to an extent that would prove harmful to the earth. And in the meantime, they assert, the inhabitants of the earth would have adjusted themselves to the gradually changing conditions. We may look upon the energy of the sun, then, no matter what its sai as inex- ; haustible. — . . Popular Science Monthly | 97 The Greatest Improvements Yet Made in Radio Reception— New Erla Reflex Circuits Using 2 and 3 Tubes Tube for tube, the new Erla two and three-tube reflex circuits demonstrate a degree of efficiency never heretofore attained. The most elaborate six and seven-tube circuits fail to duplicate their range and volume. Constructed on the same fundamental principle as the famous Erla Duo-Reflex circuit, the most powerful single-tube circuit ever built, they record a tremendous advance in radio apparatus construction. Unequaled range and power, With the three-tube circuit, nation wide recep- — Brgy eects nae by tion is obtained through a loud speaker, and the Erla radio transformers. two-tube circuit is but a step behind. Either AB 1, 2,3,$4. Reflex 1, 2, $5. ° ey : ° circuit is operated successfully with an indoor antenna, while current consumption is so low that dry cells can be advantageously employed. Guaranteeing the successful operation of these circuits, and the keystone of their amazing range and power, are Erla synchronized radio reflex and audio reflex transformers. Through their employment, the difficulties experienced until now with reflex circuits are entirely overcome Perfect synchronization and standardization of Erla au- assuring absolute stability, with unequaled purity, dio transformers guarantees sensitiveness and amplification. success in reflex work. Ra- tios—3/4 and6tol. List,$5. Further improvement results from the use of the new Erla fixed crystal detector, designed especially for reflex work. No adjustment is required with this crystal. and it is proof against jolt and jar. giving perfect rectification at all times. isla dans calibh: Gabon Complete diagrams and descriptions of Erla one, denser guaranteed to testto two and three-tube reflex circuits are presented i ee for which in Erla Bulletin No. 14, with instructions for eleven sizes, 35¢ to $1 each. installing. Ask any leading radio dealer, or write P ng ’ us, giving your dealer’s name. Electrical Research Laboratories Dept.F 2515 Michigan Ave., Chicago _ERLA Present types of detectors are antiquated by the new Erla crystal rectifier. No adjustment required. Proof against jolt or jar. List, $1. It’s Easy to Build Thin AW I5 Cords |**3,Fs’ wi ) a day, EASY/ .. | Junior mag tgs nar ae Goo wat “Wace | | Bench Special er, easy terms and new Free book. Send Saw OTTAWA Does your rippi ng, MFG. CO., mitering, grooving, rabbeting, tenon- 1801-R Wood St. ing, sanding, grinding, and many other Ottawa, Kans. operations with surprising ease and accuracy. Top 10x13”. Marr } Room 1801-R Saws 1%" stock. Dadoes %'’x%"’. Machine built entirety Log JM Bidg. of metal. Driven by \ or 1/3 h. p. ‘motor. Portable. At- , Saw } vi ittshargh, taches to any light socket. Extremely accurate. Descriptive circular tells many things of interest to workers in wood and soft metals. W. & J. BOICE, Dept. P.S.9, Toledo, Ohio sy ‘aie ate sto eee | ist on, crest, eupranten, te Zon 7 | Parga eh HOBART BROS. CO. Box P9, Troy, Ohio & ‘Popular Science Monthly —©/8

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it in Your OwnHome You may now have any known musical instrument for a week’s free trial in your own home. Play it as much as you wish. See how easy it isto learn. There is no obligation to buy; no expense forthetrial.

You may return the instrument at the cnd of a week if you decide not to keep it. Wurlitzer instruments are known the world over for unusual tone quality and ree of workmanship. They are by the greatest musicians, bands, ond orchestras. Easy Payments If you decide to buy, the Wurlitzer plan makes it easy for you to own th: instrument you want. Payments are conveniently ar d in si monthly sums--a few cents wii pay. Special combination offers on complete outfits _ a lined case, oil accessories, self in- etc. — everything you need at prac- tieally t the cost of the instrument alone.

The greatest musical catalog ever published —over 3000 ar- ticles — every known instru- a described and iilus- rated—many of themshown fn — colors. G'ves you low- the Wari and aii details of the Wurlitzer plan.

‘The Rudolph Wurlitzer Co., Dept. 1786 117 E. 4th St., Cincinnati 120 W. 42nd St., New York 250 of musical instruments. Prete ee eee eee Tee eer errr ererr rr Teer T yy 329 So. Wabash fn, Chicago Stockton St., San Francisco Send me, absolutely free, your new illustrated catalog Also tell me how I may try any instrument in my own homeat your expense, and how the Worlitzer planmatesiteasyformetobuy,. N oobligation,

Copyright 1923, Rudolph Wurlitzer Co,

The Proofs of Evolution (Continued from page 28) just as modern cats do to make themselves seem larger and more formidable to an enemy. That is the origin of our gland-caused gooseflesh. The glands of those catlike an- cestors of ours learned that one of the things they had to do in getting ready for a fight was to raise the hair. Our glands do it still. Many modern animals, the cats among them, ruffle up their hair in the same way, not by any effort of the will, but by a chemical discharged from their adrenal glands into the blood, the same chemical, in fact, that our glands produce and discharge. Embryology Supports Theory The fourth proof of evolution is the proof from human development, from what is called the science of embryology. Each human being begins as a single fertilized egg cell less than a hundredth of an inch in diameter. This cell divides into two. Each of these daughter cells then divides again into two, these new cells divide in turn, and so on until the millions of cells of the full grown human body are produced. These growing cells in the beginning show not the slightest resemblance to the human form. They look, at first, just like the little one-celled creatures with which’ we believe life began a billion or more years ago. Later on, when there are a hundred or two cells in the developing human embryo, the whole of it looks like some of the sea- dwelling, wormlike creatures that also be- longed, we believe, in the line of human ancestry. After a few more days of develop- ment, the embryo looks like a young fish, later like a young reptile, still later like a young calf or pig, and so on. Each human being in his development before birth goes through stages in body form, in skeleton, and in all internal organs that recall un- mistakably the stages of our animal ances- try that we read from fossils in the rocks. Baby’s Heart Resembles Fish’s When the first signs of a heart begin to appear in the tiny unborn child, the organ is merely a straight tube open at both ends, as the heart still is in the lancelet, a lowly wormlike ancestor of the fishes. A little later the developing human heart has two chambers as the hearts of fishes have. Still later it has three chambers like the hearts of reptiles. Only when the embryo is well on toward birth does its heart acquire the full complement of four chambers characteristic of man and of the other mammals. At one stage of its prenatal history the human embryo has slits in the sides of its neck corresponding to the gills of fishes. At a later stage it has an external movable tail like the tails of cats or monkeys. In- deed, all human beings still possess, buried in the flesh of the back, the bones of this tail. You can see them in any human skeleton or you can see your own in an X-ray photograph. The first kidney of the growing embryo is in its neck, where the kidney still is in worms. Later the duties of this first neck kidney are taken over by a structure like the kidney of frogs and other amphibians. Still later the true kidney develops and both the earlier ones disappear. Other animals show a similar suggestion by the growing embryo of some of the stages in the history of itsrace. The six-day chick, growing inside the egg, has a five-fingered hand instead of a wing, just as its reptilian ancestors had. The unhatched parrot has teeth as had the ancient fossil birds. The blind fishes that live in caves have eyes when they are very young, showing that they are descended from seeing forms. The sea-squirt, a vegetable-like animal that lives on the sea bottom, is born as a swim- ming fishlike creature that later settles down and degenerates, just as the race of sea-squirts has done in the geologic past. Every known fact about the develop- ment of unborn animals, as of unborn human beings, fits perfectly into the evolu- tionary picture. The facts do not fit into any other picture. How can we explain, for example, the fact that the human em- bryo makes use in turn of three separate kinds of kidneys, unless we admit that these are survivals, bodily memories, of the history of the kidney in the past? The fifth proof of evolution is the proof by experiment. Evolution has been pro- duced artificially. This is denied sometimes by the oppo- nents of the evolution theory. It is asserted that no new kind of creature, no new species ever has been created, demonstrably, under the eyes of man. This is simply not true. Many species have been so created, some of them by plant and animal breeders, others by scientists in the laboratory. Plants Furnish More Proofs What is the famous spineless cactus but a new species? Or the edible apple as con- trasted with the wild one, or the domesti- cated milk-giving cow, or any one of the thousand kinds of man-bred dogs? Every domestic animal and nearly every culti- vated plant is sufficiently different from its wild ancestor to be called a different species. Out of the wild “love apple’’ of the Indians, man has produced at least a dozen varieties of tomato, most of which would have been set down as different species if they had happened to be found wild. This fifth proof does not prove, of course, the evolution of man, for man has not been made artificially. But it proves the truth of evolution as a whole, while the other four proofs show that man belongs with the rest of animal creation. If evolution ap- plies to any animal, it applies also to man. The fact, too, that there are so many different kinds of living men suggests that man himself has been altering and diverging even in the comparatively recent past. Man is a domestic animal, for all that he domesticated himself; and he has altered, apparently, under domestication, just as cows and dogs and horses have done. Was Man Hairy ~All Over? Consider, for example, the effect of cloth- ing on the body hair. Apes are hairy all over and so, presumably, was primitive man. Hair was a protection from cold and rain. Modern men have lost most of this body hair and they have lost it most com- pletely from their backs, shoulders, and abdomen, from just those parts of the body, that is, which were best protected by the first form of clothing, the animal skin flung over the shoulders and tied together in front. The parts of the body that were left

100

Home Workshop Department of Popular Science Monthly

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Popular Science Monthly ee exposed, the chest, legs, forearms, and the top of the head, are just the parts where man still has some hair. Even on these parts the hair is going the stages rapidly, as men grow accustomed to more lay chick and thicker clothes. The use of hats is hav- »-finger oa ing its inevitable effect. The increasing , reptilian commonness of baldness is a sign of evolu- | adn Rely arrot has tion going on right under our eyes or, rather, b “ rds. Tha in an anatomical sense, right over them. A coltianr bese $75 seat eyes bald man who opposes the truth of evolu- pry —_ ving that = — so against the testimony of his speaker. Licensed so oad These, then, are the assembled proofs of Seat 4 pees ee sa sei evolution. First, the proof from the fossils. 19-A sent on request. or settles Second, the proof from vestige organs, such e race of as the appendix. Third, the proof from an- ic past. cient body habits, for instance the hair-rais- develop- ing action of the adrenal glands. Fourth, the f unbea proof from the development of the unborn he evolu: child. ; Fifth, the proof from the creation of ot fit intl “" — pd plants reaPiapaprny by aa 2 ‘ : o state these proofs is not, of course, to e e ae pa, make them convincing to everybody. Con- Like a good old reliable f riend - separate viction will come to the determined skeptic , ; : mit this only, I think, from firsthand contact with OU turn to your Tuska radio set with perfect faith on of the the evidence. He must see and handle the pas it is always ready to be — gg Bowes is cs fete, Ee Senet ee eee ot comings. "Yorr hike’ fees poe Gea Caer the proof ~ hp body - _ arb age a te aden reliability of performance. New models will come, as in been pro- etailed anatomical mo els, and he must pianos and fine motor cars. But few will discard the old compare these structures with the corre- and buy the new for the sake of minor refinements. The the oppo- sponding ones of animals. He must examine Tuska set represents the highest point in radio develop- s asserted the unborn human embryo at various ment to-day; you can buy it for the future with confidence. sw species stages of its growth, something that he can The Tuska is the ideal set for busy people who want ly, under do in any good medical museum. He must the thrills of radio without the tinkering. It is simple to not true: work with living plants or animals and must operate. You.turn two dials, listen, and select the exact 1, some of see for himself how he can alter them by program you want from the dozens which fill the air. rs, others breeding and selection. Nothing is forced upon you by the limitations of your set ' If he will do this—if any one will do this —every broadcasting station within hundreds of miles —I am content to leave the decision to his is within the call of your Tuska. A letter from Prince own intelligence. Albert, Saskatchewan, Canada, says, “We have tuned in 0fs clearly over 100 stations, and most of them are more Next month —The Story of the Plants than 1000 miles away.” ctus but a —How they manufacture sustenance Tuska sets are built under the personal direction of e as con- from the sun, air and water to feed man C. D. Tuska, a nationally known radio pioneer and builder -domesti- and the animals. of fine apparatus. For a dozen years Mr. Tuska has ne of the been keenly critical of all radio parts and sets bearing 3? Every FOR FURTHER READING his name. As a result, the Tuska seal is recognized as ory culti- HE best recent summary of the proofs of evo- a pred jersey New England crafts- t from its 1 Uh lane lentes Walenice Tone, ‘Pcnian. ay . d h fa by deal different #. J., 1923). A much briefer book of similar scope is, We will gladly send you the name of a nearby dealer le” of the JJ | 2 Belisve in Cod and Eyota oe Mon ee ea ee st a dozen More detailed discussions will be found in “Organic THE C. D. TUSKA CO., Hartford, Conn. ch would of this serial, yt : the firse two esha tae War First to hear across = Tuska distance records species if volume ‘ ‘Outline of Science,’’ edited by J. Arthur e sea During 12 years that ld. spon S. - gw it me a pe omen: A Tuska Receiving Set 4USKD Tuska Radio Apparatus of course Thomeon. (leery Holt and Co. wy - Voli, 1920), was the iret to receive for. DANIO bes eee ee Se | ‘ “ , e1gn amateur trans-Atlantic RADIA accumulated records of ‘not been " ihe evidences for the animal origin of code during the interna- haere Sees vane the truth man, see Man,” by Sir Arthur Keith (Home ake tional Seats. pat ne | artes tans the other sity Library, Henry Holt and Co., New York, 1912), e and ‘‘Man—the Animal,” by W. M. Smallwood 3 with the (Macmillan Co., New York, 1922). T ution ap- The Serious student must not neglect the classics of USKdG Re. DI oO evolution—‘‘ The Origin of Species’’ and ‘“‘The Descent > to man. of Man,”’ by Darwin; ‘‘Man’s Place in Nature,"’ by sO many Huxley, and “Island Life,’’ by Alfred Russell Wallace. All have been issued in many editions. ROLLED LEL ID LES ANAT LS ES EEE LEAN Sveupal Standard ae ‘“‘Toughening”’ Plaster of Paris Spanish 1 that he PLASTER of Paris can be put to many s altered, uses in the home workshop but as ordi- ARMY , just as narily handled it is more or less fragile ne. and apt to break, ~ penn if subjected to ering Went —, any abuse. This shortcoming can be reme- a ded, however, Dy ihe une of so-called | importer and SAVE ont ; of cloth- product used by plasterers for finishing ° a ie fi oft, NO PRICE ADVANCE hairy all walls and making tile effects in kitchens | the equal of any similar’ American genet about satitactory service. Cut your tire enete by these ex" primitive and bathrooms. This cement comes in ae Order direct at these special prices. cellent tires at low prices. Best tire ever seen cold and powder form, is pure -white in color, and 75 25 caltbre—7 shot—C. O. Q; Automatic. SEND st of this dries with rocklike hardness. Articles $:86 36 calibre Astra with triph cite eatery. corps 10st com- molded with equal parts of plaster of Paris 16.98 32-20 and 38 eal. swingrout cyl. sevetvens: Cor C Jers, and and Keene’s cement are fairly durable and We guarantee every gun against defective work- 0x3 06 .15.-92.08 | 35x06 933-0895 -25 the body, even can be dropped to the floor with com- | rane et of Drop Forged Steel Through $2x94.... 8.45... 1.55 | 34x4%...14.50... 3.28 d by the paratively small danger of breakage. Ordi- cyrentce. 5 © ak) MONEY unless 7ou Send Oso 198 | Box 515.25... 2.50 skin flung nary Portland cement can also be used to plus po ; guaranteed or money Te- Sana 7719.86. 1:88 | 8528 717-00... 3.00 gether in “toughen” plaster of Paris.—C. M. WIL- seein Scitation ot 3 Bo Het Doing. Oe p Reman p Sane! ns Seven Sg nee left cox, Torrington, Conn. Geet, 10, ‘Teradacd Bide; ted Angued; Cot. = RUSBER CO., 1315 teary Fa Home Workshop Department of Popular Science Monthly ae

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~O eem oe ’ nt PES IR a Ne 100 Home Workshop Department of Popular Science Monthly P Gas Flues Reduce Cost of 21 Jewel ~ Extra thin Heating Water in Home STUDEBAKER G4s consumption for water heating in _ The Insured Watch T one home has been reduced materi- p

tin le Far ee er ey

: ally by the installation of the pipe flues tc as illustrated. The tank has been in use for : about five years and: has repaid the cost of coal el 1a installation many times. _ sl 3 The tank and burner arrangement is of a OE n : ; common type, but I installed five 1%-in. I 4 } tl ‘ | AVE ; | il; i ey UE f a : t “A dollar a minute” : “That’s what I figure my spare- 5-12 GAS FLUES I time study with the I. C. S. was ee PIPE) F worth to me. It was the best invest- ° ment I ever made. I’m now making ican conmanures $160 a week—or almost twice as CASING WITH ENT FOR much in a single hour as I used to ASBESTOS PAPER make in a whole day!” O@ 4 Every mail brings letters from some of the thousands of students of the Inter- q national Correspondence Schools telling é of promotions and increases in salary as BiG the rewards of spare-time study. Only $1.00! The pat Te What are you doing with the hours in easy monthly payments. th after supper? Can you afford to let them te You get the famous Stude- slip by unimproved when Agony easily GAS SUPPLY PIPE apy Me Jewel bene > pos 4 make them mean so much? ne hour @ Pccatin or a lifetime; a choice of 54new “ g up through five flues, the heated : z day spent with the I. C. S. will prepare air then circulates down and around the ee se ee, j you for the position you want in the outside of the water tank re Regal (rae 4 . 4 a a and 5 positions—direct from the : work you like best. Yes, it will! Put it maker at lowest prices ever named ‘ up to us to prove it. Mark and mail this ; s on equal quality. } ~—s coupon now! pipes in the tank and arranged a sheet steel Write today for FREE BOOK of 4 eee eee eee ome ome eee ee ee oe es oe oe oe oe os . dit that the hot ft Advance Watch Styles. / INTERNATIONAL CORRESPONDENCE SCHOOLS casing around It, 80 that the not gases, alter e ! i Box 7654-C, Seranton, Penna. passing up through the pipes, are forced Go ain R e j Without cost or obligation on my part, pl tell me i i how I ean quality for the. position or in the subject before around outside the tank to the bottom, For a limited time we are giving away FREE with ‘ which I have marked an X: where they escape through a 3-in. stovepipe every Studebaker Watch a beautiful pattern Stude- ; BUSINESS TRAINING COURSES to the chimney.—F. C baker Watch Chain. Write now while offer lasts. 1 Salesmanship . ee ° ‘Management Advertising Mail Coupon for FREE Book nag sereranhy te) . Quickly Made Electric Yard Light of Advance Watch Styles | and Banking Law Business Engl. Send at once and get a copy of this book—FREE! yoy aed Civil Service Clerk At A cost of not more than $1 each for See the newest, beautiful, advance styles in Stude- Common School Subjects materials, it is possible to provide good baker Art Beauty Cases and Dials. Read how you High School Subjects > can buy a 21 Jewel Studebaker Insured Watch di- OFrench f) Llustrating yard lights for the farm or small town rect from the maker—save big money—and pay TECHNICAL AND INDUSTRIAL COURSES property. for it on easy monthly payments, S| Biissrteatcing Bite'Erint Reaaing | _-‘The supporting board is 7 by 12 by 18 | Write! Wihustvouonwatch i Mechante Drafteman Architect aes in. cypress, cut as shown. A 10 by 24 in. myles ‘and watch | et Free chain [ff ne + Rage oe eee — ee sheet of galvanized sheet steel or iron is offer today while it lasts. } eed Ritomattie Work” | DeNe Ina amo Studebaker Watch Co . S utomobile W ° i i oi ek) ey verted V shape (img iz Dept.239, South Bend, Ind. [ 4 Steam Engineering () Radio [[Mathematics and nailed to the STUDEBAKTR WATCH CO. : : Name.......... — edges of Please send me your Free Book of Advance Watch it —s Sane the board to form Styles and particulars of your $1.00 down offer. a Radaes "7 A light porce- Name -oaeseeseveeseeese ssrsseeneen eae cnees l i ES lain receptacle is MIME. nis vcpsvinena nese beweeneeasiiih bak ‘ i Persone residing in Canada should send this coupon to the screwed to the . Cit State | ; nee teat —-. Canadian, Limited, board in the cen- Hood cunticetin saprst saad CETTE ROLE... Ce °

ter, and, 5 in. reflects light downwards NEW-TREAD TIRES Mikes ie point and 5 or 6in. at each side of the center, ATA0* ON THE DOLLAR holes 54 in. in diameter are bored for the insertion of two. porcelain insulating tubes. Hie a Two )4-in. holes are bored 2 in. inside the f Send No Money! lower corners and another near the upper SO SG/- ! Hi Ve Ae season's s tire ire bill motwithteanding” ad point to take 2%-in. lag screws. The

: ' j ; j

prices. For a limited pe caly we Pa tt te ee light should be placed about 15 ft. high.

J | Zreaded Tires ae ihustrated — at less If the wiring is to come from inside the built on the best carcases money can buy. building, fasten the board in place after re- Special Sale Prices moving the insulating bushings and then = gad si28 ao sees 2.98 bore two holes through the building wall in Sx3 "4.08 "1.38 | wtK*S.68 *2 line with the holes in the board and pass the ‘oes ves fie 8.00 2.48 tubes through both board and wall. If the > ie wae. tesleut ens sce wiring is to be entirely on the outside of the 297 = .. a Bis — ae Sas building, no insulation tubes are required & LOCALITY. ‘ . * " DIAMOND-TREAD TIRE WORKS paint.—J. R. Kuntz. peas ani ance ES a z 3295 S. Morgan St., Chicago, Illinois CONSUMERS CO. Dept. 1-AZ 1265 Broadway,WN, ae 6©=6 (102 Home Workshop Department of Popular Science Monthly

aia ae hae Shiba

ed ee [ a = | nn et ee me de | i Gageeris Workbench |

Page 85

v! alance nents, Stude- Insured 54 new tments, 1ronism om the named IOK of

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Home Workshop | Department of Popular Science Monthly "a

——___ Pipe Frame Supports Workbench (Continued from page 78) in. oak; the other boards are 114-in. pine. The boards are fastened to the pipe sup- ports with U-bolts and make a solid bench top. The grinder may be turned to face the end of the bench, but the arrangement shown is preferable because the belt does not interfere with feeding long rods through the lathe spindle. With an outfit such as this, the amateur will have little difficulty in handling a large variety of work. The few suggestions that follow may, however, smooth over some of the problems that are apt to perplex any worker who has not had much shop ex- perience. As most lathes are provided with index plates to give the sizes of gears necessary for thread cutting, the only figuring the amateur usually has to do is for special threads. A method used by many practical men is to express the required lead as a fraction and multiply the nu- merator or divide the denominator by the number that represents the lead of the lead screw. If you wish to cut E 27 threads in 5 C in., the fraction Fig. 2. Howturning and, Will be 5/27, boring tools should be which, multiplied mounted by 5 (represent- ing the lead screw), gives 25/27, the propor- tion of the gears. I have assumed that the spindle and stud of the lathe are evenly geared; otherwise the actual lead of the screw is disregarded

VZZZZ, Vigan

b al UZ ZETIA a threads an inch the lathe would cut with even gears on stud and screw. In cutting threads, care must be taken that the cutting edge is at the exact center of the work. Perhaps the hardest part of the amateur’s work is to keep his tools in proper shape. At the outset he should buy a center gage that also serves for grinding screw cutting tools and setting them at exact right angles to the mounted work. To do good work a lathe tool must be mounted properly. A position 5 degrees above the center of work to be turned, as shown at A, Fig. 2, is the approved prac- tice. In setting the cutting edge of a boring tool, however, reverse this rule and place it about 5 degrees below the center (Fig. 2, C). As with outside tools, great care must be taken to see that the boring tool is securely supported to prevent any downward spring. Tools Must Be Well Supported - A chattering tool is caused, as a rule, by the cutting edge being too great a distance from the support. At B, Fig. 2, attention is called to distance X, which in all cases is to be kept as short as possible. It is also im- portant to remember that the turning tool must be kept at right angles to the center line of the work or the work will have a tendency to turn either large or small. As much amateur work is done in brass, a word or two regarding the rake of a tool may be helpful. There are two rakes used,

(Turn to page 102) and in its place is used the number of -

Learn Mechanics In & Wecks At Sweeney's HY not make your work play by working at bp ater: you like? If you like machinery, if you are mechani- cally inclined, and are game, are not afraid of working in grease, gasoline, you and I will get along together fine. I cannot teach any man a trade if he does not like his work. If you don’t like to work in the dirt, grease, among machinery, you are not mechani- cally inclined. If you are, write me, and write me NOW! Don’t put it off, but get busy, get your pencil, fill out the coupon in the corner, and mail it to me for my book. GET INTO THE AUTOMOBILE BUSINESS BY THE Sweeney System of Practical Experience The Great Million-Dollar School, world-famous, and the success of my thousands of graduates are due to the Sweeney system. This is what you get here and can’t get anywhere else. I have taught over 60,000 men to be expert repair men, chauffeurs, tractor engineers, garage owners, etc. I am proud of the fact that I was selected by the U.S. Government,to train 5,000 men for mechanical work in the service. I teach by using tools not books. You learn as you do the real work with your hands. I estimate at least 20,000 Sweeney trained men Be Your Own Boss are in business for themselves. Twelve million automobiles are running. Countless opportunities everywhere. : Ce If you prefer electrical work I have Learn P ractical Electricity he. finest practical electrical course in the United States. You can qualify in three months for a real job by the Sweeney System of Practical Experience. You don’t need to be an engineer or scientist to install, operate and repair all kinds of electrical machinery. We teach with tools. You learn by actually working on our $150,000 special equipment in this world-famous Million-Dollar Trade School where we have turned out 60,000 trained mechanics. | PAY YOUR RAILWAY FARE jom2"%r'ne ose Sic you live I rebate your fare, thus making it as easy for you to come here as if this Million- dollar school were located in your own town. Simply send name today for my big 64-page catalog. Shows hundreds FR of pictures of men at work in the school. Teils all about wages, profits, opportunities in auto and tractor and electric business, we Re

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MONARCH Any desired blade locks into position Jr. 9" Lathe ps aga wy Bg 4 214 ft.bed— | | stant disappearsin the hendle. bench legs CHANGES BLADES instantly!

-- Automatically 245 No loose blades - no lost blades. Once yuu use it - youwon't be without it, <p NOW money order or check for Guaranteed THE MONARCH ‘MACHINE TOOL CO. Dept.59 = Santa Ana, Cal.

— SioNey, ont | | Seer ee SETS

Home Workshop Department of’ Popular Science Monthly 103

—— 2? ote D.- SPOS. Bane, Oe | | | aa

Page 86

f . ta et - 7 : i) t aN > 45 1 a 5 } 1 > : = & i 2 ;

Home Workshop Department of Popular Science Monthly Creat Inventors Now Teach You How to Invent Edison says ‘‘Invention is a Science and should be taught as a Profession’’ Thousands of inventions are needed today. Just one little idea can bring you fortune and fame. The world is waiting for new inventions in engineering, chemistry, household articles, radio, SL a oe and other fields—and will pay big money for even the simplest idea. Little things like the tin bottle cap, the crimped hair-pin, the rubber on the end of a pencil brought their inventors hundreds of thousands of dollars. Couldn’t you make some equally simple invention? Haven't you ideas that could be turned into money? es ee / Inventing isn’t a mat- RAYMOND FRANCIS YATEs ‘¢t, of blind tuck—it isn’t a question of guesswork. Invention is based on certain prin- ciples, just as any other profession. It followsa definite course of procedure step by step from the origination-of the first idea to its final de- velopment on a commercial scale. Learn at Home in Sparelime Hitherto, every inventor had to work out these principles of invention for himself. For every successful inventor knows and uses these principles,

He knows WHAT TO INVENT and HOW TO INVENT. But now you can learn in a few months what it took great inventors years of discouragement and terrific struggle to acquire. Fifteen famous in- ventors have now revealed, for the first time, the secrets of invention. They explain how to originate ideas, how to develop and perfect your ideas, how to atent your inventions, and how to sell them to your advantage. In short, they make it amazingly easy for you to become an inventor, simply by learne ing the whole wonderful science of invention, step by step, from beginning to end. It requires just fascinating moments of your spare time at home. First Course of Its Kind This is the first course in practical Invention that has ever been devised. Now you can take Edison's advice and actually learn HOW TO INVENT— how to make invention a profession! In simple, easy-to-understand language, you are told how successful inventors work; you learn how to use the secrets of invention that convert a simple little idea into money. Inventive Science A wonderful new book has just come from the press that tells all about the Science of Invention; that shows how great inventors work, how little ideas have made fortunes; how you, too, can easily learn the secrets of successful invention. This fascinating Book will be sent free to all those who are genuinely interested. Send for this Book today, as only a limited number are available for free dis- tribution. Write your name and address on. the coupon below, or send a post card NOW! There is no cost or obligation. BUREAU OF INVENTIVE SCIENCE Dept. 29, Wisner Building, Rochester, N. Y. Bureau of Inventive Science, Dept. 29 Wisner Building, Rochester, N. Y. Please send me your free book, The Science of In- vention.”’

Automatic Photo Print Washer Changes and Agitates Water

ALTHOUGH I have tested nearly all the photographic print washers placed on the market during the last five years, none has given the satisfaction of the one illus- trated. This is built on the principle of the Tantalus cup of the ancient Romans. When the water level rises to the height marked X, it enters the downflow tube and almost all the water in the tray is then siphoned out with a rush. By regulating the flow of water from the faucet, the washer will operate every two minutes. Another advantage is that the hypo- laden water at or near the bottom is re- Ly FAuceT

As soon as this photo tray is nearly full of aan: it is emptied automatically from the bottom moved first. The prints are also agitated during each water discharge, so that at the end of 15 minutes they are absolutely free of hypo. The inner tube is )4-in. and the outer tube 1-in. brass. The inner tube has a small funnel-shaped piece soldered inside the top. The outer tube is capped with a piece of brass soldered airtight. About 44 in. from the bottom of this tube a series of 14-in. holes is drilled to allow the water to flow into it from all directions. The washer illustrated is made from a large tinned dishpan, but the principle is the same with any kind of container. The only requirements are that the inner tube must have a discharge length of from 2 to 6 in. below the bottom of the vessel. If a tin cup or basin filled with water is placed under the washer so that the siphon tube dips into it for about 1 in., the down rush of the water is increased still more.— JOHN H. SCHALEK, Pittsburgh, Pa. Making Radio Tube Ends «pe pieces for tubes on which homemade radio coils are to be wound can be made satis- factorily with no materials other than hard cardboard and some liquid glue. Suppose the tube is 3 in. outside diameter and 1/16 in. thick. Cut several 2%-in. disks to make a pile a little more than \ in. thick, and an equal number of disks 314 in. in diameter. Coat the disks evenly and thinly with glue, string them together, using their center holes as a guide, and put them under a heavy weight to dry for at least 24 hours. When the glue is dry, clean off any sur- plus, smooth the edges of the disks with fine sandpaper, and finish with two or three

LAYERS OF CARDBOARD 3

TUBE END For radio coils Pipe Frame Supports Workbench (Continued from page 101) a positive and a negative rake. The cutting edge of the positive rake slopes away from the work and is used in cutting steel and other hard metals, while the cutting edge of the negative rake slopes toward the work. If a tool with a positive rake is used for turning brass, it will ‘‘bite in.” A side rake of 14 degrees (see Fig. 3) is generally used for medium hard steel, but 10 to 12 ‘degrees is better for harder stock. The back rake of 8 degrees is con- stant for all ma- terials. A full set of lathe tools is something that very few mechanics possess, but it is advis- able to use the right too! for the right job if good work is to be done. Lathe tools are forged from either tool or crucible steel and can be tempered by heat- ing slowly and evenly for a distance of about 2 in. from the cutting point. After heating to a cherry red the required dis- tance, the tool is dipped in cold water to a depth of only 14% in. After the point has cooled, it is removed from the water and carefully cleaned with carborundum cloth and wiped clean with a piece of waste or cloth. The heat in the shank of the tool will drive the temper toward the cutting edge and when the edge becomes a brown straw color, the tool is immersed in water. A word of caution in regard to the use of tools: Keep them sharp. Do not run them to destruction before regrinding. Do not overheat when hardening. Do not heat too rapidly. In grinding drills, use a gage that gives the angle of the point. If you arein a hurry to drill, increase the feed rather than the speed of your drill.

T

Typical turnin: tools, showing side an back rake Fig. 3.

Breast Drill Mounted on Bench Does Light Turning "TUBNING taper pins, filing down bolts, truing valves and similar small repair- ing jobs, as well as coil winding, can often be done with a breast drill, if other means are lacking. One way to mount a drill for this sort of work is to use two small strap brackets bolted to the bench as shown. The same

WALL STUD... STRAP BRACKETS~. i , ’

Two easily made brackets support the drill for winding coils, light turning, or — heavy drilling brackets also serve for attaching the drill to a wall stud or post for use in heavy dri ling. A hinged worktable with a lever handle

Sr pos as’ wit bet —_————-_— - ia oe

NAMe.. 2. sceeeeececeeeccecscescnecnsceseners coats of flat paint or enamel. End pieces can be made along the lines indicated for Adieoas made in this way are surprisingly strong-and use when drilling. This is a handy arrange- —————<-. ° ee can be drilled and even tapped for machine ment for drilling holes through shafts and oe Seg) a re screws.—H. G. bolts for cotter pins.—S. L. K State 104 Home Workshop Department of mes Science Monthly

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1 cloth aste or 001 will g edge . straw use of 1 them Yo not 2at too t gives . hurry an the nch bolts, repair- often means rill to i ling. andle od for ‘ange- s and Home Workshop Department of’ Popular Science Monthly 103 —_—_— Small Adjustable Table Attaches to Bedpost STRONG rack or table for the sick- room that can be attached to the bed- post and swung around to various positions, as well as raised and lowered, can be made with little difficulty, as shown. A strap hinge is bent to go around the bedpost and the point of one leaf of the GEDPosT RON ROD BENT & END FLATTENED Wali: Ea The table raises, lowers, and swings WINGNUT | hinge is then formed into a loop to take the table rod. A hole is bored for a bolt and wingnut to clamp the leaves of the hinge around the post. By heating and hammering the rod, it is bent to the shape indicated and one end is flattened and drilled for the screws used in attaching it to the board. A convenient size for the table is 12 by 12 in., and it can be made of 14, %, or %-in. stock. Felt is glued to the inside of the hinge to prevent the metal from scratching the bed- post.—W. E. KING. Adjustable ‘‘Plank’’ Saves Time in Painting and Paper Hanging T° AID me in my paperhanging and painting business, I use a staging plank that is adjustable in length. The one plank serves all purposes because it can be compressed to suit a small room or pulled out for a large room. It is inexpensive and can be made by any one. Ten boards 1 in. thick, 3 in. wide, and * 7 ft. 6 in. long, and 10 blocks 114 in. thick, 8 in. wide, and 6 in. long are required, as well as two 14-in. bolts 12 in. long, four pieces of strap iron 11 in. long, six 3}4-in. bolts, and a small can of glue. Take five of the 6-in. blocks and five of the 7 ft. 6 in. boards, and put them to- Waar would Popular Science Magazine be without its wonder- ful photographic illustrations? These pictures would be impos- sible were it not for such lenses as Bausch & Lomb TESSAR PHOTO LENSES Ask your dealer for booklet, ‘‘What Lens Shall I Buy?’’—or write to us. Bausch & Lomb Optical Co. Rochester, New York New York Washington Chicago San Francisco London TO Write for FREE Book | | “LIGHTING FIXTURES” Mead THE SECRET || GHTING SCHOOL DOOR | Direct from manufacturers, STUDENTS & It contains a vital mes- }| | , Completely wired including GRADUATES Paes BE sey a, for Catalogue No. 24 and NU KAPPA SIGMA Dealers’ proposition ae is ERIE FIXTURE SUPPLY CO. | Desk A, Erie, Pa. gether as shown, first gluing them and then bolting them up with large washers at each end. Make another similar section and fit the two together, bolting on the four iZione This decorator’s plank can be shortened cr lengthened to suit any ordinary room strap irons 6.in. from the center of the whole plank so that they are 1 ft. apart. A bolt can be run through the two center boards near their inside ends to serve as stops to prevent the “plank” from coming apart when opened in a hurry. The complete staging plank is safe, convenient, and a genuine time saver.— Loy E. OwEn, College View, Neb. ce Says Use Nu-Gas bo Cook and Heat Up-to-date homes being built with- (« *) out coal bins because there’s a SS better, cleaner, easier way to cook, bake and heat, by burning free aie. “‘Don’t buy coal at present price,’’ says a Domestic Science Expert. Don’t buy it at any price, You can get far better results by burning free air and oil in the way science has recently discovered, The government does it; the big ships do it; factories do it; and new homes are being built without coal bins or wood-sheds because their owners have adopted the new, clean, dustless, dirt- less, laborless device which fits in any stove. Oil and Free Air Make Wonder Heat Science has shown that one part of coal oil (kerosene) the cheapest of fuels, can be mixed with twenty parts of air (bya remarkable burner) and the result is a wonderful heating and cooking gas. Cheaper than city gas. No fires to build. Heats at t twist of the wrist. bad, 4 tial Aes ioncad — > Heats largest rooms in a few moments on coldest morning. Heatsoven evenly for baking. No dirt, smell Free Book About Remarkable Way to Burn Air . Learn how to cut housework in hed Learn ab arpgiodine ty ew genet — to save by having all the heat you want but AGENTS way has been found to cut use- Oly when you need it. Learn cheap way to #50 to #200a | jess parts, sothat, ofall burners, have the warmest, cleanest, cosiest home in week. Fullorspare the NU-HEAT (the latest one} town. Just say “send Nu-Heat information time, Fersone!co- | is the bestand lower in price.In Free.” Mention if you have heater, range or quick for exclus. | stalled in a jiffy in your present furnace. No obligation to you whatever. ive territory and | range, heater, furnace—then yau Man Coa, ~ Aad case | are no longer a slave to coal and Wade Hill ufecturing A twist of the wrist fh} on arising. Intense fire almost instantly wood and the expense, labor and Dept. 941, St. Louis, Mo. Home Workshop Department of Popular Science Monthly 105

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. ij 4 +] j $ | . 4 4 } Home Workshop Department of Popular Science Monthly | WL,DOUGLAS $700 & $890 SHOES W. L. DOUGLAS SHOES ARE E ACTUALLY DEMANDED YEAR AFTER YEAR BY MORE PEOPLE THAN ANY OTHER SHOES IN THE WORLD They are made of the best and finest leathers, by skilled shoemakers, all working to make the best shoes for the price. The quality is unsurpassed. The smart styles are the leaders in the fash- ion centers of America. The wide rangein kinds, styles and prices provides suit- . able shoes for every occasion, busi- ness, travel and motoring. Shoes of equal quality cannot be bought else- where at anywhere near our prices. If you have been paying high prices Z for shoes, why not try a pair of ; W.L. Douglas $8.00 shoes, the shoes that hold theirshape? They are exceptionally good value. Frankly, is it not worth while in these days of high cost of living for you to save money on your footwear when the opportunity offers? For thirty-seven years W. L. Douglas name and portrait have stood for a high standard of quality and dependable value. For economy and satisfactory service, wear shoes that bear this trade mark. Ask your dealer for W. L. Douglas shoes. Look for W. L. Douglas name and the re- tail price stamped on the sole. Refuse substitutes. ident FoR TREATED CREM SS SHOWING HOW WL Be Seta TO ORDER SHOES BY MAIL. POSTAGE FREE. 124 Spark Street, Brockton, Mass. TO MERCHANTS: If no dealer in your town handles W. L. Douglas shoes, write today for exclusive rights to handle this quick-selling, quick turn-over line. THE STAMPED PRICE 1S YOUR PROTECTION § AGAINST UNREASONABLE PROFITS SAVE COAL Make 10 tons do the work of 12 to 20 tons ACK of air over the surface of the fuel bed in your furnace is cost- ing you extra money for coal, and re- ducing the amount of heat you should get. There is a simple, scientific device that remedies this condition, that makes your furnace breathe, that gives you quick, steady heat, and more of it, that reduces your coal bills 20 to 50%. 3 iriaae genuine UNDERWOOD Yes, $3 d ts this uine di standard Shi wan Word Rebuilt “Under. This device is the Crown FuEL SAVER. The Crown FUEL SAVER elie: in your e. Then—small monthly fits the feed ayments, or if ‘convenient —— cash. door of any er ee 3 you heating plant. It provides by _ Means of nat- —= ural draft the supply of super-heated air, necessary to burn the rich gases that rise from the surface of the fuel bed. (See illustration). These gases ordinarily are lost, going up the chimney as “smoke."” The Crown saves this unnec- essary waste of fuel. This means a tremen- dous increase in heat and a corresponding reduction in smoke. The CROWN does its work automati- cally—requires no attention, and will last as long as your heating plant. Any mechanic can put it on the feed door easily and quickly without injury to the door. Don’t wait. Don’t hesitate. Have a CROWN put on your heating plant now. That’s a sure way of saving money. Write for our booklet— Fag Rnb eK g. WHY PAY RENTAL? "TEN DAYS’ FREE TRIAL See for rself! the typewriter ten . You oo be satisfied or = entire trans- won’t cost you a penny. t tod: Get our oe catalog and $5ii particulars. ter Emporium IPMAN -WARD MIG. Send by return mail Bargain Offer No, 2146 of a Standard Visible Writing Underwood. ~ hearty og an order and does not obligate me Te Name eeescocoe eeeeseeeestesecseseeees Streetor R.F.D.No....0.0-cccccccccces 4 4 ‘‘Making the Coal Bill Look Like 30 cents,”’ and for details and price of CRown. As the CROWN comes in 4 sizes, give name and make of furnace and approximate size of grate. DISTRIBUTORS WANTED The Crown is the fastest selling specialty on the market. Offers the opportunity to get into a big profitable business. Write for distributors’ proposition telling of past busi- ness experience. CROWN FUEL SAVER CO., 12 N. 10th St., Richmond, Ind. Home Workshop ‘‘Kinks’’ that Will Save You Time ‘T= breakage of small drills, which is a constant annoyance to amateur me- chanics, can be reduced greatly by breaking the drills short in advance. The smaller sizes of drills are too long for gen- eral use in a hand drill, but broken in two they are stiff enough to stand up quite well. This dodge saves drills without number. For drilling in lathe or drill-press the full length can be used with only ordinary care. Using small taps is even more provoking than using small drills because when they break off in a hole it is difficult and some- times impossible to remove them. When a tap begins to stick it is usually because of the chips clogging. To prevent this, back it out a turn or two and then go ahead until it sticks again, repeating the process. If the hole is deep, this alone probably will not suffice and the tap will have to be backed all the way. As a tap does practically all its cutting at the end and with the first few full threads, not much is gained by having the rest of the threaded part very hard and brittle. As an experi- ment, the writer drew the temper of several small taps, leaving full hard- \ ness where the real ten \ work was done. meray Rs This was scoom- Sey 5 seks 2 some plished by sticking from a tap the point of the tap into a cut potato far enough to cover the point and half-a-dozen full threads. After bright- ening the flutes with fine emery cloth, a hot soldering copper was applied to the shank. The color began to change and run down toward the point, and, when the color close to the point had become a rather dark brown, the tap was plunged quickly into cold water. The potato prevented the end from losing its temper. After much use these taps are still intact. Drawing the temper must, however, be done carefully or you will find that the tap is spoiled by over-softening. Working tool steel in the lathe is usually thought a hard proposition for the amateur, but it is not difficult if drill rod is used where the job is not too big. This rod is of high grade tool steel and comes in 3-ft. lengths perfectly straight and truly round. It is annealed and easy to work. The sizes range from 1/16 in. up. From this steel it is quite easy to make reamers to smooth and true small holes. Round off the end of a piece of drill rod the size of the hole, taking care that the curve is truly circular, and file or grind down the end at an angle of about 10 degrees. One point is important: If a section should be made across the reamer just where the rounded end starts, it should show an exact semicircle; at that point the breadth of the flat should equal the diameter. Harden and temper the point to a light straw color. Drill the hole a shade under size and run the reamer through. If the tool is made properly, the bore will be dead smooth, polished and true. This “‘kink” seems to be almost unknown among ama- teurs.—HOWARD GREENE. SMOOTH CUTTING REAMER ma manok ww ma eA ae ee 6 al 106 Home Workshop Department of Popular Science Monthly

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TAP eamer Partly point right- a hot hank. down - close dark r into e end h use g the lly or ed by sually ateur, ; used d is of 1 3-ft. ound. e sizes make holes. od the curve vn the . One uld be re the 1 exact of the a light under If the e dead “kink” y ama- Home Workshop Department of Popular Science Monthly 105 Identifying Walnut and Mahogany (Continued from page 77) men of burl wal- nut, used often for ornamental overlays and in- lays on fine fur- niture. Compare it with the stump walnut figure di- rectly below. Even experienced furniture deal- ers often describe a stump figure as burl walnut. One is obtained by slicing up huge burls or knots that grow as ex- crescences on some walnut Walnut cut somewhat > cross-grained so that the trees; the other pores appear as_ short comes from near ashes the base of the tree where the wood is beautifully rippled, usually for not more than a foot or two above the ground. The crotch veneer, of which a particu- larly striking specimen is shown, comes Microphoto- Oya ml Ke 716 times of the en ain of yel- = w birch, which often is used as a substitute for walnut or i} mahogany. he pores hardly can be seen without a lens and are far too small to be mis- taken for those of the sive woods The end grain of red gum magnified 74 times. This is another wood that can be fin- ished to look very much like walnut or mahogany, but its pores are even finer than those of birch. They cannot be seen without a glass Microphoto- graphs furnished by Forest Prod- ucts Laboratory, United States Forest Service from just below the juncture of two large limbs of a tree. The sliced wood specimen is from the southwest, probably Texas, and has a distinct contrast of light and dark. It is an interesting panel because it shows almost perfectly the picture of a hound’s face. Four characteristic mahogany veneers shown on page 77 are—crotch, raindrop, fiddleback, and striped. The names are sufficiently descriptive in each case to in- dicate the kind of figure. There are several other figures often en- countered, notably the well known rotary (Turn to page 106) more expen- | _ TRADE-MARKS AND PAI EN I COPYRIGHTS SPECI AL OFFER FREE OPINION AS TO | PATENTABLE NATURE Before disclosing an invention, the inventor should write for our blank form ‘*Record of Invention.’? This should be signed and witnessed and if returned to us together with model or sketch and description of the invention, we will give our opinion as to its patentable nature. Our Three Books Mailed Free to Inventors Our Illustrated Guide BOOK HOW TO OBTAIN A PATENT Contains full instructions regarding U.S. Patents. Our Methods, Terms, and 100 Mechanical Movements illustrated and de- scribed, Articles on Assignment or SALE OF PATENTS, Patent Practice and Procedure, and Law Points for inventors. }OUR TRADE MARK BOOK Shows the value and necessity of Trade-Mark Protection and gives information regarding Trade-Marks and unfair competition in trade. OUR FOREIGN BOOK We have Direct Agencies in all Foreign Countries. We secure Foreign Patents in shortest-time and lowest cost. LIST OF PATENT BUYERS SENT FREE IDEAS WANTED: Send for LIST OF PATENT BUYERS, containing unsolicited Letters from Manu- facturers and others WISHING TO BUY merito- rious patents. There isa great demand for NEEDED INVENTIONS. We endeavor to assist OUR clients in the commercial development of their inventions. —— a ae ks i 3 ws i Specification and Drafting Departments, Victor Building, Waihingtea, D.C. h ea VICTOR J. EVANS & CO. Dh Nn tH Patent Attorneys i | i iit Hy j Wilh Wi New York Offices Offices i i 1007 Woolworth Bldg. 714-715 Liberty Bldg. mt Chicago Offices, 1114 Tacoma Bldg. San Francisco Offices, Hobert Bldg, ! i Main Offices, 760 9th Street, Washington, D.C. ! Gentlemen: Please send me FREE OF CHARGE your books as described above. , i Hl Home Workshop Department of Popular Science Monthly -107

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en TE ie BA ot ligt 106 Home Workshop Department of Popular Science Monthly UNITED STATES "Identifying Walnut and Mahogany AND | (Continued from page 105) | FOREIGN _ eut figure, which is obtained by cutting a | j log around and around. The striped fig- ure is obtained by splitting a log into four | parts lengthwise and slicing a flat side of each quarter. Matched veneers, so often mentioned by | eabinetmakers, are obtained by reversing | and matching two pieces from the same log or stump. In this way magnificent pat- You * Bd 4 G HTS _ Hints on Choosing Furniture terns are obtained, sometimes like a branch- Even in the best furniture construction, ' ing tree or like a conventionalized human it should be noted that the hidden or less We help our clients, PA } EK : S conspicuous parts are made of relatively |} ee eee ie inferior boards or veneers and that the ideas —having facilities

ate Adee Neher

es ee

CAN YOU think of a simple, practical idea that will fill one of the many re- uests we have on file for new inven- tions? It may meana fortune for you. Thousands of things are needed RiGut Now. Your brainscan help. Send to- day for our great new book—“‘Invene tions and Trade Marks, Their Protection and _ Exploitation’’ and learn more about. making money from ideas than you ever knew before. It tells many things that are wanted, t0O. A postal will do— . itis free.

eee | or animal figure.

PATENTS

4 increases its efficiency or usefulness, ADVERTISED . choicest figures are reserved for the more scariest catia For SALE FREE Any new article, machine, design important parts. Solid walnut or mahogany Advice free. In INVENTION And or improvement thereof, or any new furniture is sometimes made, but it is ex- i, Pan 4 MANUFACTURING {1 combination of parts or improve- ceedingly expensive. Solid construction is f ENT | ments in any known article which necessary {or elaborately carved furniture, AMERICAN SUPPLEMENT. | | but where plain panels predominate, ve- INDUSTRIES, INC.

Published for the may be patented, if it involvesinven- J | neered stock is usually preferred, since the Bend for free sample 1h | tion. choice of fine figures is greater and the ee rs copy. One year'ssub- |} | f IF YOU HAVE ANY grain can be “matched” more easily. arene, FR ecrintion Svc. When a dealer says that a piece is walnut 3) NEW IDEAS or mahogany throughout he usually means : which you feel are useful, practical that it is made entirely of the one wood, ; and novel, take prompt action tow- some parts being solid and some veneered. ‘| ard protecting your rights. If you Whenever “combination” is mentioned have invented any new machine, or new combination of parts or im- provement, or new process or design,

in connection with walnut or mahogany furniture, it means that while the larger panels and conspicuous parts are genuine, Send Drawing, Model the frame or posts are made of a substitute

° wood and finished to match. Also, when ; - or Description a piece is described as walnut or mahogany | ; To the Man With an Id fa ir of it for information as to procedure “finish,” it is frankly a substitute. The use | [ie ea 1} to secure protection. of these two terms is often criticized as be- | [ix Bc nl Pye heey ing x a} 8 . " ° | i cient service for his ¥} WRITE TODAY FOR BLANK FORM ing misleading, but they are nevertheless in M prompt, legal protection and the H : general use. ) ; 3) development of his proposition. 4 i Record of Invention By following the suggestions given above, jag Send sketch, or model and description, [ie | any one can decide for himself with reason- | figg ft advice as to cost, search through [ip 4 to be returned tome with drawing, bl heth ta ci : fy prior United States patents, etc. Pre- if description or model of your idea abie accuracy whether or not a given piece ij liminary advice gladly furnished with- a aoa 1 arg * f of furniture is genuine walnut or mahogany. meq Out charge. | omptiy upon receipt Dy me oO tee My experience and familiarity with =| your idea I will write you fully as to fey Vatious arts, frequently enable me to ; procedure and costs. iwee accurately advise clients as to prob- i Spring Holds Drying Films | Coe ee No Charge for the Above EY Book ; . = ae et of valuable information and form Information —*S USING a spring as shown, a photog- i en ty your idea, free on All communications are held in _Tapher can dispense with the numerous RICHARD B. OWEN strict confidence. My personal, care- spring clip holders ordinarily needed in the IF - Patent Lawyer : 2 ful and thorough attention is given dark room. One spring holds a number of feu ©=6 Owen Building, Washington,D.C, to each case. I offer you efficient, |. ee reliable and prompt service—based ee upon practical experience. Highest references. Write today for free book ‘‘How to Obtain a Patent.’ This book will if give you valuable information, and : it may save you much time and effort. Send for it NOW. _ My practice is devoted exclusively 3 to United States and foreign patents 7 and trade marks. Very probably I can help you. Write today. CLARENCE A. O’BRIEN Registered Patent Attorney 224 Southern Bidg., Washington, D. C. CLARENCE A. O'BRIEN, 224 Southern Building, Patent Attorney, Washington, D. C. Please send me your free booklet, ‘‘How to Obtain a Pat- ent" and blank form Record of Invention without any obliga- _ fon on my part, ib ETE eee ay oe

PATENTS TRADE-MARKS, COPYRIGHTS AND PATENT LITIGATION Write for advice and instruc- tions how to proceed, costs, etc. Hand Book with illustrations of 100 Mechanical — = : ; Movements sent free on request. ALBERT E. DIETERICH Bending the spring to insert a film Patent Lawyer and Solicitor Successor to Fred G. Dieterich & Co. 60 Ouray Bida. WASHINGTON. 1. C

negatives and there is no danger of the films being scratched. ' To insert a film the spring is bent at one point with the fingers, as indicated, a corner of the film inserted and the spring P ATENTS Sot dpues ta Aemeted wo released.—J. B. FLOWERS, Gloucester, N. J. Caines shaaan a evidenced Patents of value. Book, Patent-Sense, * Lacey & Lacey, Sab Fee Week C macen 1eee:

Old Brush Useful for Staining EEP a wall brush that has been worn

ite divin so ost dupb ssp Fb) <¥o¥ Rikon ; i i to a chisel edge for applying stains. For 8 el covering large surfaces, such as trim or | SPH OQ in P (write PLainty) 777" partitions, use a brush 4 in. wide. “ in riZes

See top of page four in front of book for details |

108 Home Workshop Department of Popular Science Munthly »o © Sb io Aes oe ee Ne a eh. corte ak ae Le

oe 1 q

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» ITIGATION Mechanical 3 fs ICH , Co. TON. D.C cso sreninaa gta tts eerily tinea ae tant etn ein sem sen tain Home Workshop Department of Popular Science Monthly -107 Drawing Board Attachment Makes Perspective Easy gurgnbisg mechanical drawings can be made with considerable speed and accuracy by the use of a simple adjust- able attachment that automatically sup- RIGHT POSITION CENTER — la V4 G._ & 2 tl METAL PIN" Extension arm with a pivoted straightedge pro- vides the means for drawing “‘vanishing’”’ lines quickly and accurately plies right-, left-hand and, if necessary, “over” vanishing points. The attachment corisists of an extension that can be bolted, as shown, to two corners or the upper edge of the board. The thumb- screws fit tapped holes in metal pins in- serted permanently in the board. At the end of the extension is a pin that serves for pivoting a long, thin, straight- edge. A small brace under the arm helps support the weight.—F. C. W. Making a Bookrack Cabinet COMBINATION bookrack and cab- inet with small drawers and pigeon- holes often is a desirable addition to a flat top desk or a table used as a desk. The design shown is particularly simple to con- The bookrack and cabinet struct and the shape of the ends and the dimensions can be changed to suit the re- quirements and taste of the builder. The ends and bookshelf are oak, dressed on both sides to a 34-in. thickness, and the bottom and back are 14-in. whitewood. The drawer fronts are of oak, and the whole is finished to match the desk.—J. V. Non-Tipping Ink Bottle SED on the tilting sur- face of an adjust- able drawing board or artist’s table, the holder illustrated keeps the ink bottle {\) level. It is made of two strips of light sheet metal about 3/ by 5 in., and two short strands of malleable wire.—JOHN.M. Pipp, Muncie; Ind. PATENTS Seventy-six Years of Practice HE firm of Munn & Company filed its , . & first application for a patent in 1846, and for - seventy-six years has endeavored to keep pace with the inventive genius of the United States. An experience of many years is at your disposal. If you have an invention which you wish to patent, send your sketches or model together with a description of your device, explaining its operation, and you will receive prompt, courteous attention. Write for our Handbook on PATENTS A full and complete booklet on Patents, Designs, Trade- Marks, Foreign Patents, Copyrights, Labels and Patent Office Practice with an explanation about our methods, terms, etc. All communications strictly confidential Keepin touch with the inventions of the world byreading SCIENTIFIC AMERICAN The MONTHL Y MAGAZINE with a special appeal to every man of inventive genuis. Recent rulings of the Patent Office, descriptions of the latest patented inven- tions, legislation and court decisions affecting patents, are noted in this authoritative publication. MUNN & COMPANY Patent Attorneys 683 Woolworth Building, New York City Scientific American Bldg., Room 3, 625 F Street, Washington, D.C. 801-D, Tower Building, Chicago, II. 602 Hobart Bldg., San Francisco, Cal. $25.00 in PRIZES “07s Pp ATEN TS invexnon oa cesine TO LEARN HOW TO SECURE A PATENT, send for Our Guide Book, HOW TO GET A PATENT, sent free on request. Tells our Terms, Methods, etc. Send model or sketch and description of your invention and we mamas eee eee Will give our Opinion as to its ; patentable nature. —_,.................... (RANDOLPH & CO. pa Bales bape ate | 130 F St,,.N. W., Washington, D. C. Home Workshop Department of Popular Science Monthly 109 ~.. oanany...| iii i ie

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An ambitious young man of Indiana believed that when he qualified for a bigger job, his chance would come—with the concern that employed him, or some other. He did not stop with dreaming or believing. He acted by enrolling for one of our practical spare-hour correspondence courses. Before he had completed his course, a responsible position opened with a competing company. He writes: “I have been asked by directors and large stock- holders to take the position made vacant by the promotion of Mr. B This marks a big upward step for me.” Make no mistake. The eyes of executives are on you. They are measuring you up for more responsibility. They are more than willing to give you your chance. Get ready for your upward step by learning about our distinctive mail-instruction service and putting yourself under the guidance of earnest, competent instructors who will take an interest in all your problems.

Some of our Correspondence Courses School of Commerce School of Engineering Architecture Automobile Courses Building Construction Civil Engineering Concrete Engineering ‘ting Courses ng . Electrical Engineering Foremanship |

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and writin: Radio Tele Writeg: a Steam 1 nooriag Strac Drafting High School Miscellaneous Junior High School First Year High Schoo! aeneene High 0 oh mercial High Schooi Trade High School Applied Psychology Sperich 5 ™ Physical Directors’ Training Poultry Husbandry Mark and mail this coupon for our friendly counsel ee ee

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Home Workshop Department of Popular Science Musnthly

Oil Cans Form Storage Drawers for Shop Use SMALL drawers or boxes for storing bolts, washers, nuts, cotters, drills, reamers and other small parts and tools, can be made up quickly for use in the home shop from ordinary 1-gal. oil cans. One side and a part of the top and bottom of the can are removed and a portion of

SHEET 7 Liga GUIDE The runners for these cheap and handy tin draw- ers are made by cutting and bending the ends of the cans

TURNED-OVER RUNNERS each end is doubled over and bent, as shown, to form runners. These runners are engaged by guides of sheet metal fastened to the under side of the bench, shelf, or other support.—M. P. J.

How to Make Ferrules ee THE home workshop it is sometimes necessary to make ferrules. Often they can be found ready made; for example, the brass caps on the ends of the carbon rods in a much used variety of dry cell serves well for light use. Small flanged unions, such as are used for gas lines on autos and on supply pipes for wash basins, make sub- stantial and ornamental ferrules. For most purposes ferrules of brass or copper pipe are quite satisfactory, and short lengths and scraps can be obtained from plumbing shops and garages for next to nothing. The tubing in old chandeliers also is useful. To cut the ferrules the right length is a simple matter if a machine lathe is at hand, but the work can be done quickly on a wood lathe if a cylinder is first turned so that it Li a = Two ways of forming strong tapered ferrules WON

will slip inside the pipe and a file is ground to serve as a tool. In the latter case, leave the work for a short time on a steam pipe or near a stove so that the ferrule will ex- pand enough to be removed easily from the wooden core. When a cone-shaped or other odd shaped ferrule is required, wrap No. 22 or 24 copper or soft brass wire around the end, as shown, beginning at the small end so that each turn will crowd the one before. After fas- tening the end, give the whole a coat of solder. This produces a strong ferrule, does not take as long as one would think, and always fits. Tinned iron wire can be used but is not as good. Cone-shaped ferrules also can be made from copper or brass gauze. Cut the gauze to fit with snips, allowing a lap of 1 or 3/16 in. Recess the wood under the lap to improve the appearance and hold the gauze in place with a couple of tacks after it has been rapped or rubbed into shape with a hammer. A coat of solder is then applied. —EpGak A. STANTON, Seattle, Wash. |

110 SS 1 a

eo .,. I» ons oe. 29. 2... Perfect Performance Crosley Model X Gives Better Radio Reception ti popularity of the Crosley Model X is increasing daily, This four tube set—still priced at $55—maintains its marvelous record of bringing in distant sta- tions. Amanfrom Chatham, Va., writes: “IT own a Crosley Model X. I have picked up over 130 stations in the U. S. and have listened to Havana, Canada, North Dakota, all Texas and ships at sea.” You can depend upon an instru- ment bearing the name Crosley. - For Sale By Best Dealers Every- where. Crosley Manufacturing Co. Cincinnati, O.

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ppeue ee ND FOR S¥NI THIS f ORM DON’T LOSE YOUR RIGHTS TO PATENT PROTECTION Before disclosing your invention to anyone send for blank form *‘EVIDENCE OF CON- CEPTION” to be signed and witnessed. A sample form together with printed instructions will show youjust how to work up yourevi- dence and establish thesame before filing ap- plication for patent. As registered patent at- torneys we represent hundreds ofinventors all over the United States and_ Canada in thead- vancement of inventions. Ourschedule of fees willbe found reasonable. ‘The form “Evidence of Conception,’’ sample, instructions relating to obtaining of patents and schedule of fees oa ; request. Ask for them,—a post card will do. N TRADE MARKS.

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See top of page four in front of book for details — Home Workshop Department of Popular Science Monthly

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ce Se ee ance 1 X ption Crosley zg daily. riced at irvelous ant sta- ., Writes: stations ened to Dakota, | instru- sley. Every- gz Co. nati, O, Send For Free Catalog anyone F CON- ed. A ructions our evi- ling ap- tent at- ators all thead- 2 of fees vidence relating of fees st card of Popular Science Monthly 109 How to Lay Out and Drill Your Radio Panel By D. H. Palmeter HE smooth mechanical working and the neat appearance of a panel-mounted receiving set, depend to a considerable extent upon the accurate laying out and drilling of the radio panel. A well spaced panel with cleanly drilled holes is a delight to the eye. One with holes poorly alined and disfigured by burrs and uneven countersinking is always a sign of amateur workmanship. As in nearly all home workshop under- takings, a good drawing is the first essen- tial. Note whether the drawing represents the front or back of the panel. If you make the layout yourself, draw’ it full size as viewed from the rear of the panel. That is because a panel should be laid out from the back. If the drawing you are working on shows the front of the panel, remember that holes located from the left edge will be located from the right edge when you are laying them out on the panel itself and vice versa. Composition panels, already cut out toa number of standard sizes, can be obtained. Laying out a radio panei with accuracy is easy when the right system is followed Get one of the right size and lay its polished” side down on two thicknesses of clean wrapping paper placed on a smooth, level bench or table. The location of each hole is indicated by the intersection of two straight lines or by a single line and an arc of a circle. You will need the following implements: a square, either a try-square, draftsman’s T- square, or a combination machinist’s square with graduated blade; a pair of machinist’s dividers; a scriber or a phonograph needle held in a refillable pencil, and a center- punch. If the square has no scale marked on it, a rule also will be required. Locating the Holes A study of Fig. 1, which shows a typical. panel layout, indicates where the holes are located. When these are on the same horizontal or vertical line, one hole is laid out by measuring from two edges of the panel, as at A and B; the dividers are set for the distance between the holes, and the arcs are struck, as at C, D, E, F, G, H, and I. . Holes located on the circumference of a circle are “‘stepped”’ with the dividers. Next the intersections are marked with a centerpunch and drilled with a No. 42 drill. - Turn the panel face up and mark with lead pencil all the holes that require the smallest size drill. Drill these first. Then mark and drill the next larger size, and so on. In this way you will not make the mistake of accidentally drilling a %4-in. hole where a %-in. hole should be. (Turn to page 110) The largest one-man shovels in the world, equipped with General Electric motors, take eight dump cartloads at a bite, and can take a bite a minute, Its shoulders never tire GeneralElectricCom- pany makes many different types of motors, some small enough to wind a clock, some large enough to operate these giant shovels; but ali designed to help electricity do more for humf&n ser- vice at a lower cost. A giant worker—excavating over three hundred thousand cubic feet a day! In three days, six hours and thirty-six min- utes, it could handle material equal in cubic contents to the Washington Monument. Think for how many centu- ries the world wasted its most precious possession—human lives—in labor that electricity can dol SwULaae Saasss#s, World Radio Auto Batteries WRARUEIESSISS; PHLESILAAARBAYW We defy price competition; a glance at the prices now will co mvince you that the World ae is best buy on the Ba immediately, Express C. O. D. Begin 100% battery service at half cost. Mail order today. | Automobile Prices RADIO PRICES 2 Volt ” $5.00 (For W.D. 11 Tube 6 ea ¢ Am. eg Give year and inter at ear World Battery Co., 1219 S. Wabash ro — Chicago __ €,,

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An ech FIL ETENY Fs ore ae a a Sa wipes epeme te egitim aie ope ON he sO A scr “A aia ib Meee WE LTT ene ee ee a ey Lab ote ~ 110 Smoking the peace pipe in wartime As any ex-doughboy will tell you, a thousand tons of tobacco distributed over a fighting force of 2,000,000 men showed good intentions, but it didn’t fill the need —not by a few million pipefuls. Even today letters still come in from veterans who have forgotten the horrors of war and remember only the thrill of ‘‘a real American smoke’”’ in France. For one, Hugh Livingstone, Adjutant of Yankee Division Post, No. 272, V. F. W., remembers: Providence, R. I. Larus & Brother Co., Richmond, Va. Gentlemen: My introduction to Edgeworth took place over in the training area in France under cir- cumstances that left a lasting impression of the good qualities of Edgeworth. One night, after a hard day’s work, my bunkie drew a package from home, one of those mysterious affairs that might contain everything but what you wanted. After due ceremonies of guessing he opened it and the first thing we saw was‘the blue box of Edgeworth. All further operations aden until we filled the pipes.. After ‘using the French tabac for. several weeks and burning our mouths and throats to a raw state you can imagine how cool and satisfying that Edgeworth tasted to us. We smoked until we were ordered to bed, and I fell asleep smoking. You can just bet a letter went home for more Edgeworth. Since that time I have used about every kind ot tobacco that is put up, but it is Edge- worth for me when I can get it. Thank you for putting such a satisfying and cool tobacco on the market. . Gratefully yours, (Signed) Hugh Livingstone. Probably any. good American smoking tobacco would have brought the same joy to Mr. Livingstone and his bunkie in France. But it is a fact that when Edge- worth makes a friend, more often than not it is a lifetime affair. Edgeworth’s one great asset for most smokers is that it is al- ways the same. You can buy a pack- age in Chicago, another in New Orleans, another in San Francisco, and each package will give you the same cool, satis- fying smoke. If you are not an Edgeworth smoker, you are cordially invited to accept some free samples of both Edge- worth Plug slice and Ready-Rubbed. Just drop a post card with your name and address to Larus & Brother Com- wp: 59 South 21st Street, Richmond; a., and the free samples will be forwarded to you immediately. If you will also in- clude the name and address of your tobacco dealer, your courtesy will be appreciated. To Retail Tobacco Merchants: If your jobber cannot supply you with Edgeworth, Larus & Brother eapeny will gladly send you prepaid by post a one- or two- dozen carton of any size of Edgeworth Plug Slice or Ready-Rubbed for the same price you would pay the jobber. How to Drill Radio Panels (Continued from page 109) Where screws are used to fasten parts to the panel, or the panel to the cabinet, the best looking job is obtained by using countersunk flat-head screws. Here is where care makes all the difference between an amateurish and a workmanlike job. All standard, flat-head machine and wood screws require what is known as an 82- degree countersink. This provides for the ' ' | ?y = 2 | “5 HOLES eo RS ' 2 OFF WITH Divi os : | 78 “+—}-4 * pare as cage gos ERR ' P75 ey ee er “ered —— | —-}- “nied Ai fo -. me 6 2m zi His ge at io , Se —j+ ~ Pa (+ ; | mi i “ls a ia = ' All the layout lines are scribed on the rear of the panel, using square and dividers correct angle, but it is equally important to countersink all the holes to the proper depth. To do this, one of the screws may be tried from time to time while counter- sinking until the head of the screw kas its top surface just a trifle below the surface of the panel. If much countersinking is to be done, a handy gage can be made, as shown in Fig. 2, by soldering a metal strip to the head of a oe | ‘.-GRIND TO ‘SHAPE FIG.3 Gage for countersinking and a scraper screw that has been cut off short. The size of the screw may be stamped on the handle. If a countersink becomes dull, it can be touched up with an oilstone or a car- borundum stone. A dull countersink will throw up a heavy burr and occasionally a new ccuntersink that is very sharp will “chatter” and cut a rough hole. This is easily remedied by backing off each cutting edge slightly with an oilstone. If burrs are formed, they may be re- moved with a tool made from an old file as as shown in Fig. 3. e Protector for Vacuum Tubes ANY a vacuum tube has been broken be- cause a pair of pliers or a screwdriver has been dropped upon it acci- dentally. Such mishaps can be prevented by protecting the tube, as shown, with a section of cardboard mailing tube. Notches are cut in the lower edge if necessary, to clear the socket bind- ing posts. It is especially advisable to protect the Aiune tubes on board-mounted ‘Y°f sets in this way.—L. R. Prevents eebhege HOLE TO VIEW FILAMENT \ TUBE SOCKET Home Workshop Department of Popular Science Monthly = WRITTEN COLD A‘ (GUARANTEE _ SS _—_WV = Greatest tiresale sae rns Goodyear, & " ® Goodrich, Firestone, Fisk and other fine makes o going a at t record-breaking prices. = pre almost new OUR PRICES. DEFY com PETITION TIRES Tubes TUBES 39x3, $1.90 $ 90 32x4% $3. $3.75 $1.65 30x3% 2.00 .90 33x4 3.75 1.65 | 2 3023) 2.50: .90 34x4 4.00 1.65 « a 31x4 2.75 .90 35x4% 4.25 1.65 32x4 3.00 1.40 36x44 4.25 1.65 33x4 3.25 1.40 35x5 4.25 1.95 34x 3.50 1.40 37x5 4.25 1.95 Just $1.00 t for o> tire ord: Balance » Soa — an ak te a eeitiea assures you eight. months eee service or ie ~ ms INTERNATIONAL TIRE, CORP. ™@ so East CHICAGO, ILLINOIS Prices Reduced On All Standard Make TYPEWRIT ERS LowestPricesinYears Wewillship any make you choose for one week’s trial. Underwood. Royal, L. C. Smith, Remington, Oliver, ete. Easy Terms f2” n Standard Largest Dea Typewriters 654 W. Randolph St, Dept. 1429, Chicago, Ill. 60% ofMarket Price Hundreds of Draws ~ gtr List f ang ~ Sond Be Now Latest bulletin includes Unpaid Loans—sent free. oe ibes Diamon d Bargaios in de- tail, gives renteed cas —- values. Fs ains p prices paid unlimited exchange privi- Metin” No obliwation. “1 ‘ 4 iga' —Write ‘ostal we Pet ed LYON & HEALY, 72-81 Jackson Bivd., Ghieate SEND FOR THE INTERNATIONAL CATALOG Our net price list. FOR EORD—Pricce 8 dae I pm s ue gamers to INTERNATIONAL soy WORKS, te wo Ohe SL oy ul. Motorcycle Bargains SAVE 25% to 65% on rey used and Rebuilt Motor- cyci Indian, Excelsior, Harley- Im Cleveland, d, Side Cars, John- tor Wheels, Evans Power C i Popular Science Monthly | Insulin—A Science Miracle | SLSR t t ¢ a ( 4 1

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bd at AD au He peer Sk Set = 8 Gee Home Workshop Department of Popular Science Monthly 111 Concealed Aerial Is Sewn inside Automobile Top A COMPACT and inconspicuous method of arranging an aerial on an automo- pile is to sew the wire in a loop inside the top of the car. The necessary length of insulated wire, say 80 or 100 ft. of No. 20 single or double cotton covered wire, is sewn in an .or- derly arrange- ment to a strip of black or brown cambric chosen f LOOP SEWED TO LINING OF TOP to match the Aerial is completely color inside the hidden top of. the car. The rectangular loop is then sewn to the top. In the case of a closed car, the loop may be concealed completely by covering it with fabric of the same texture as the cover- ing. In an open car the loop will fold, when necessary, with the top. Two installations made in this way have given most satisfactory results, and a more inconspicuous arrangement could hardly be desired.—P. O. R. Trimming Ornamental Trees T° TRIM ornamental trees quickly and uniformly is not easy, even for an ex- perienced gardener. An amateur can do it well, however, if he uses a templet of metal, wood or cardboard, made as shown. The shape desired for the tree is first drawn to small scale on a piece of material no larger than a hand-glass and then cut out. One man looks at the tree to be trimmed through the templet from a distance equal to the height of the tree or farther and gives directions to another man who does the actual trimming. When the outline coin- cides with the opening in the trimming gage, the men move around a trifle and in this way quickly make the shape entirely symmetrical. Any number of trees can thus be trimmed exactly alike.—L. C. M. Clamps for Clothespins UGS, blank- ets and stiff articles of cloth- ing cannot easily be hung on a line with ordinary clothespins so they are often merely thrown © over the line. ny m ih ‘ ai Tt Much better than that - method is to hang them with cheap iron clamps, which can be obtained in any five and ten cent store. If the rug or other article is fine, use blocks or strips of wood on each side to distribute the pressure of the clamps, as shown.—N. G. NEAR. “Vitalics by a Long Shot” FREE | A Vitalic Bike Cap to boys who will write for it ROCTOR DISBRO’S experience with Vitalics is not unusual. Thousands of boys have written us their approval of Vitalic tires. They wear and wear and stand up under the hardest kind of usage. Vi- talics can be depended upon. They have been the choice of boys and men for over ten years. No tires equal Vitalics. Big Bicycle makers like Excelsior, Iver Johnson and others put nothing except Vitalic tires on their finest wheels. “Tougher than Elephant Hide” is a slogan that de- scribes Vitalic qualities exactly. CONTINENTAL RUBBER WORKS 1964 Liberty Street Erie, Pa. Bicvcle Tires “ TOUGHER THAN ELEPHANT HIDE y Boys: Tell your father or big brother that he can now get Vitalic Cords for his automobile with the same ‘‘Tougher than Elephant Hide’’ quality. Oo Jewel — 7 Burlin lington ~ bfireproof k resilient A aon ng nt material easily form over ctically any kind of of floor. Laid oem % toch thick. ang al Floor does not crack, peel or come loose f: foundation. tA continuous, fine ined, anes. non-sli: — No crevic s to gather grease dirt, nate + lieal Floor fo for Kitchen, Pasty, ™ Bath Re pen. Hotel. et Facto * San Gultling Reliroad Sea tion, H caw sever, a beautiful, substantial floor is d desired. colors. information and sample wie FREE of your first ian second choice of color. Imperial Floor Co.. 145-147 Halstead St., Rochester, N. ¥. A Success for 15 Years Home Workshop Department of Popular Science Monthly 113

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Eedeecmnantanneanuniiteiadl et Kasih eh pet tice ns cn eteneseers merlin tien the ae See re a rama Sndbes xcs secpeabeide aaekse A tape ng ete Fane Daitafiiin alts on) The Ideal Tube for the Call of the Open RE you spending your vacation in the North Woods—at the seashore—in one of our many great na- tional parks, or are you motoring across country? In any event the new Cun- ningham dry battery de- tector and amplifier, type C-299, makes it possible for you to take a radio receiver, which will be light in weight, compact in design, and high- ly efficient in operation. It is the special filament in this tube, having a current so low that it may receive its supply from standard No. 6 dry batteries or even from ordinary flashlight batteries that makes possible this new and interesting applica- tion of radio. The receiving set you now have can be readily adjusted to use this new tube and be a source of use and pleasure on your vacation trip. In any event your dealer can give you useful suggestions for the purchase or constriction of a highly efficient and practical portable set. A Specially Designed Tube For Every Radio ” Use Cunning- Patent Notice: («7"in- are covered by patents dated ot ded 1-15-07, 2-18-08, and others issued and pending. Licensed for amateur, ex- perimental and entertainment use in radio communication. Any other use will be an infringement. ‘ae MS fun | Home Office: 248 First Street 154 West Lake Street Chicago, Illinois San Francisco, Calif. q Popular Science Monthly Insulin—A Science Miracle (Cortinued from page 24) nationalities, the Irish and the Jews show an especial susceptibility, and the death rate from the disease consequently is large in states where these two stocks make up a large portion of the population. Estimates as to the number of diabetics in this country vary between 500,000 and 2,000,000. Despite the undoubted success of insulin, the medical profession has issued a warning that it is not to be regarded as a magic or instant cure. In fact, it is not a “‘cure’’ at all, since it does not destroy the causes of the disease. It is a remedy, merely supply- ing to the body an element that disease has removed. Injections of insulin every day for long periods are necessary to successful treatment. Stopping the treatment, it is said, causes the disease to reappear. A high degree of skill is necessary in the administration of insulin. The quantity to be injected varies according to the pro- portion of sugar in the patient’s blood, and an overdose of insulin, medical au- thorities say, may result in serious com- plications. Meanwhi'e Doctor Banting, lifted sud- denly from obscurity to worldwide fame, remains, so his intimates say, the same un- assuming, serious-minded, diffident young ‘man he was when he returned from the war, wounded and wearing the Military Cross, to begin his professional life in Toronto. The people of Alliston, Ont., where live his father and mother, each past the three- score-and-ten mark, and his brothers and sisters, take immense pride in the fact that he has become the town’s most noted son- He still speaks of Alliston as “home.” Began Life as a Farm Boy Before leaving Alliston 12 years ago to enter the University of Toronto, Doctor Banting was a farm boy, performing chores around his father’s homestead like hun- dreds of other boys in the agricultural sec- tions of Canada. His teachers say that he made no particular mark in his studies, although he was studious and persevering. Up to the time he left there to study medi- cine, most of the people in Alliston believed he intended to enter the ministry. Imme- diately after graduating from medical school, he entered the Canadian army, be- | coming a battalion physician with the rank | of captain. He was wounded at Cambrai and invalided to England, where he re- mained until 1920. Referring to this incident of his career in the army, his mother recently furnished an | illuminating sidelight on his character. **He made a promise that he would write to me every Sunday when he went away to college,” she recalled. ‘He never has failed to keep that promise. When his right arm was useless from wounds, he learned to write with his left hand so that I’d continue to get my letters.” The Canadian Government recently granted Doctor Banting an annuity of $7500 for life in recognition of his discovery of insulin, and the Ontario Legislature has appropriated $10,000 a year to create a department of research in the University of Toronto. This will be known as the Bant- ing-Best Chair of Research, and Doctor Banting has been appointed its first incum- bent at a salary of $6000 a year. Today the eyes of the scientific world are turned toward Canada, eager to glimpse the new activities of the young physician who has become a world figure at an age at which most professional men are struggling for a foothold. | ——$———— Home Workshop Chemistry Simple Formulas that | Will Save Time and Money OW often have you asked: What is the best stain for this particular job? What is the best cement for this difficult joint? What will fill this crack? What will bleach out this spot ? These and scores of similar questions constantly arise in every home workshop. Often they are not answered satisfacto- . rily. The home worker may have the best of tools, but the chances are that he doesn’t keep on hand even the simplest chemicals and has no idea what can be accomplished by home workshop chemistry. The following is the first of a series of articles on this subject.—The Editor, VERY homeworker should have certain chemicals always at hand in his work- shop. If properly selected, these chemicals will serve many useful purposes. At times nothing more than filler for “at others the cracks may be required; repairing of a, leaking crock, jar” or washtub may require instant attention; or, perhaps, the splitting or crack- ing of certain work on hand may require a special type of glue difficult to obtain but easy to make, if the few raw materials necessary are available. To make a list of chemicals is, however, quite difficult, because each worker is in- terested in his own particular problems and a hard and fast assortment may not suit all | needs. It is advisable to have on hand the more common solvents, not only for the removal of stains but also for the making of | varnishes, glues and the like, together with | Mending a cracked crock , a few other often used chemicals. A good list is as follows: Acetone Alcohol Rosin Turpentine, both Ammonia Precipitated spirits and Copal resin chalk ozonized Gum tragacanth White lead Acetic acid Carpenters’ glue Benzol Shellac (orange) | Ether Glycerin Gum arabic Linseed oil Gelatin Red lead Muriatic acid Celluloid chips Calcium chlorid Waterglass Usually one or two ounces of each chem- ical is sufficient. If, on occasion, large quantities are necessary, there is always time to obtain them. It is always best to buy special chemicals only when it is known that they are to be used. An incident showing how useful a few cherricals can be, occurred recently in my own home. A stone crock cracked just be- fore I was going to use it. It was impos- sible to obtain another of the same size for the experiments I was carrying out and it simply had to be repaired at once. Waterglass was smeared over the crack and allowed to penetrate. Then.a little calcium chlorid dissolved in water was poured in. This made.a covering of cal- cium silicate over the crack and the crock could then be used. How to make the best use of the chem- icals listed above will be told: in iin articles.—ERNEST BADE, Ph.D. Home Workshop Department of Popular Sadenien Monthly

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‘kshop try nulas that | ave Time rd Money ee What is ular job? | difficult -? What juestions orkshop. itisfacto- . have the are that ven the no idea yy home a series e Editor, ve certain nis work- chemicals filler for thers the Home Workshop Department of Popular Science Monthly 113 Warren Radio Loop, Cut Away to Show Construction, 4. TYPE. FOR “EVERY SET THE BEST DEALERS Bal 6 inches sq directi very (176-1000 meters) 6 inches sausrenone 2 700 metere) 18 lichea square—directional oat = Type BL-a820 (200. 18,000 m iene ormach coil. a Send for Bulletin U-102 V-DE-CO RADIO MFG. CO. Dept. 0, Asbury Park, N. J. Garage Door Release Combined with Lamp Bracket ‘WO added conveniences for the aver- age garage are a lamp in front of the doors and an extension device of some kind by which the doors can be released and opened without leaving the car. Both of these can be obtained at once by a fixture made as shown. A bracket. that GUIDE FOR CABLE TO RELEASE DOOR CATCH HANDLES sere iit Bis fete)! COURSE IN TWO YEARS YOu ARE BADLY 4 bia wer HANDICAPPED pentni ae: 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- 0 sing ¢ russ ing. You can’t hope to succeed in the face of this handicap. But you STUART'S PLAPAO- can remove it. Let the American egg Bg oe Bd School help you. chemico applicators made One handl the th h | po yny ew pA ~~ aia FIT YOURSELF FOR A esha oc canta eee BIG FUTURE This course, aie ee press caviar tke extends 5 ft. is fastened at the left side of which has been prepared by some of ked crock , ae eee tee and above the door. It is made of two America’s leading professors, will Bens M eS See eee ee. pipes, one of which serves as a waterproof broaden your mind, and make you » few raw Ps ee —— camse_qonauereg. Geand Oxts housing for the electric light wire. The keen, alert and capable, It is com- : ! org ee Oe lg me recovery is | other contains a pull cable attached to the plete, simplified and up-to-date. It however, orove tt by sending “Frit oe? Shi FREE door catch. covers all subjects given in a resident ker is in- Welte same ep Cogpen smd emne 5) M When approaching the garage, the driver school and meets all requirements of blems and Plapae Co., 790 Stuart Bldg., St. Louis, Mo. pulls one handle to turn on the light and a High School training. From the ot suit all | — pee hein tha hteass i tii abit aidehideh teams then the other to release the door. first lesson to the last you are care- hand the The installation shown makes use of fully examined and coached. y for the counterweights to dpen the doors, as they making of | swing in; with outward-swinging doors, the USE SPARE TIME ONLY ther with — hinges must be set slightly out of plumb so Most people idle away fifty hours a . A good | oe oe va or gta when the week. Probably you do. Use only catch is released.—P, ¥, I. one-fifth of your wasted hours for a3 ae at goa study and you can remove your rcipitated A Permanent Loft Ladder present handicap within two years. halk You will enjoy the lessons and the — mets own Sen poor. __ HAND GRIPS manotetes you will - will well ao PF seathe - 4 tepay the time spent in study. Fes cnad Depends onde 3 | | of loft ladders in ae : terglass needs no batt: ttery. . rer ® barns, shops and iit Check and mail the coupon NOW one conn, ‘hedged ta cote DY mail J ~~ | storage buildings | |B8ION Il fee= for full particulars and Free Bulletin, c ‘ - : j on, large ciamnc" Cearm| | T° wooden, 2 4) American School neg d tase For the auto, summer BM é stronger and ae gee ree sry camp or around Nowe, MUM Oe gag) | more durable > prexel Ave. and 38th St., Chicago AZ, | ys best to this ttle wonder today: EB @SUdoYoY- MEO) NTO type of metal | nisi enbéihiapunbinialetaiadbenodamana is known ——— ladder is usually Aeemitenin: Sieoed ag worth the mod- Dept. H-675, Drexel Ave. & 58th St., Chicago ul a few AGENT 500; | erate additional Send me full information on the subject checked tly in my PROFIT | cost in making and how you will help me win success. d just be- : the installation. . en as Impos- “oe a ee Free on The ladder ‘(l- em gbree. eon “Attombble Besinece -Photoplay Writer e size for on 5 and st won Pang T ee lustrated, which | Made of pipe and rods = Givi i ~~~ Shop Superintendent ut and it can put them on, Big demand everye | jg one used in a ~---Basiness Manager ~..... Steam : where. Liberal offer to general agents, | 15+, on a Virginia farm, illustrates a cheap | ‘Accountant and Auditor “Sanitary the 7 METALLIC LETTER CO., 433A N. Clark, Chicago | and durable form of construction. The up- “= Beaftara and Designer me, ee nA . 3 rights are 1-in. wrought iron pipe, bent as | ~~~fisctrical Engines 4 -- ales ater was You Can Save 35% shown, and attached to the studding with | -~..General Ed meation noe ive Expert zt ck , lag screws. The rungs and upper braces | «Business Law onal @ croc ramet are pipe of the same size, notched at the | pa faery ir | ends and attached with 14-in. steel rods | “=™ he chem- ParcelsPostpaid ™*K2° 229 and nuts. The upper end of the ladder pro- | 4... following a with Sean ees jects 3 ft. above the loft floor to form a sub- on. Give aame, year, model number of your car stantial handhold.—L. M. C. Dept.E8 Cincinnati,O.- Home Workshop Department of Popular Science Monthly 115 yr, lw On... , Ok,

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ieee hres pre atnineerhihemmtre et cena Sareea eisceoneciranyes : ae I * 114 Home Workshop Department of Popular Science Monthly WB5ICH ONE will help you win fameand fortun? For half a century the world’s great artists have used Conn instru- ments. The stars of today in con- cert bands, symphony, opera and popular orchestras, have risen to fame playing Conns. They accord a generous measure of their suc- cess to these superb instruments. You will profit by following their example. Winsuccess, profit, pleas- ure with a Conn, “the instrument of the artists.” Remember, with a Conn you get these definite points of superiority: Easier Blowing: each tone responds to the slightest lip pressure. Perfect Scale: accurate intonation in all } registers. Most Reliable Action: lightest, easiest and surest, whether slide, valve or key. Beautiful Tone: our ex- clusive hydraulic expan- sion process insures accurate proportions and perfect carriage for sound waves. All exclusive Conn features, at no greater cost. Highest honors at World Expositions. Free Trial; Easy Payments Send post card for details, men- tioning instrument that interests you. Conn is the only maker of every instrument used in the band. We also make high grade violins and drums. Dealers and Agents everywhere FACTORY BRANCHES: Conn New York Co. Conn Detroit Co. Conn New Orleans Co. Sonat Cleveland Co. Conn Chicago Co. Conn Seattle Co. Conn Portland Co. Conn Atlanta Co. C. G. CONN, Led., $32 Conn Bldg., Elkhart, Ind. ON WORLD'S MANUFACTURERS ORCHESTRA INSTRUMENTS Attractive Picture Frames Cost Little By E. E. Scott : HE cost of frames and not the value of the pictures is often what makes it necessary for art stores to charge nearly prohibitive prices for the kind of pictures we all should like to have in our homes. The process of lithographing has become so perfected that reproductions of the old masters can be made in exact detail and coloring, but a square foot of excellent art, costing only 25 or 50 cents, requires about 41% ft. of frame worth from 50 cents to a dollar a foot. Therefore a small picture of good quality ordinarily sells at from six to eight dollars. The simplest way to cut down this cost is to make your own frames. It requires only some good, straight grained whitewood or other suitable wood, a smooth plane, a rabbet plane, a miter box, and a square. A picture frame vise is a good help, but it is not essential, especially as a useful vise can be made as shown on page 78 of the April POPULAR SCIENCE MONTHLY. When you have decided on the design and size of frame you will make, square up Inexpensive reproductions of the old masters are set off to excellent advantage in these plain, easily made frames your strips with the smooth plane and cut a notch or rabbet for the glass with the rabbet plane. If a wooden rabbet plane is used, a strip can be nailed on the side to form a guiding fence. If a rabbet plane is not available, the notch can be cut with chisels or even a jacknife, or done at a car- penter’s shop on the saw-table. . The front face of the strip is then treated in any of the ways shown or in whatever combination of bevels, rounds, grooves, and rabbets that suggest themselves as being most appropriate. Be particularly careful in planing bevels, as a slight vari- ation may ruin the stock. The thin grooves are made by first scratching the strip with a nail filed to a sharp point, and finishing the line with a three-cornered file. In preparing material for frames, it will be found most convenient to plane it in short lengths, bearing in mind the size of the frame and that the strip should be a little more than twice its width longer than one side of the picture to allow for the miter cut. To finish the pieces, sandpaper them well and stain them mahogany or some dark color with a commercial penetrating stain. Follow this with a coat of thin white shellac as a primer for the three coats of varnish that should be laid on. Each coat should be finely sanded after it is thoroughly dry. The final polish to the outside coat is given with powdered pumice and oil rubbed on with a cotton cloth. Cut the completed strips to size in a miter box and, using a plane sharpened to . a razor edge or a sharp chisel, clip off the rough surfaces left by the saw. Then fit the corners accurately and nail together with fine brads, after well coating the joints with glue. The larger frames may be held to- gether with very thin, long screws, as illus- trated. The selection of the width, color, and design of the frames is necessarily left to the maker. No hard and fast rules can be laid down giving the size and proportions of the frame or mount. In general, it may SLENDER SCREWS A few of the many moldings that can be made by combining bevels, rounds, carvings, and rabbets be said that the farther away the picture is supposed to be, the wider the mount and frame should be. A landscape with con- siderable detail should have a narrow frame, while a portrait like that of Rembrandt by himself should have comparatively a much wider mount. The reason for this is that one function of the frame, from the artist’s point of view, is to surround the picture with a space of “‘silence’”’ or to blot out all disturbing details near the picture. A per- fectly plain frame often sets a picture off better than one of the hand carved variety, which tends to call attention to itself and away from the picture. When the frame is finished, visit a glazier and select a thin sheet of window glass free from bubbles. This should be cut 1/16 in. smaller than the dimensions of the glass rabbet. The glass, picture, and cardboard, wallboard or wooden backing are then placed in the frame and held with thin 1-in. brads. Over the back is glued a sheet of heavy wrapping paper to prevent dust from filtering down between the glass and the picture. The paper is moistened before gluing so that it will be as tight as a drum- head when dry. Making Watertight Joints for Wooden Boats and Tanks A SIMPLE trick by which the amateur woodworker can make a boat, tank, tray or watering trough watertight is to compress a groove into the edge of each board with a tool such as is illus- trated. The edges are then planed until the surface is even again and butt joints are made in the usual way. When the boards come in contact with the water, the narrow strips of compressed wood swell and ail cracks close tightly. A tool for making the grooves, if a forge is available, can be bent from a 10-in. length of strap iron, or one will be made cheaply by any blacksmith. The head of the tool is flattened’ to take the heavy hammer blows.—A. C. NAUDE, New York. The grooving tool Don’t miss the tool contest announced on page 90. prizes are offered for letters from readers. 116 Home Workshop Department of Popular Science Monthly

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Home Workshop Department of Popular Science Monthly 115 ttle —— 21 JEWEL a Fe Spectal

Secret Combination Safeguards | Novel Electric Switch | eld to- w= LTHOUGH simplicity itself, the secret | 3 ilite. aL electric switch illustrated cannot be | operated successfully by those who do not | : aol know the combinations. It has hundreds of | htt din combinations and any would-be meddler | canbel | | ao will give up in disgust or tear it away to get | . at the connections concealed beneath it | ortions EA R | it may before hitting on the right sequence. As a No YD switch to prevent the accidental or mali- | me v CONCEALED WIRES TO CIRCUIT , SE While other watch dealers are raising their prices, WOGEEN GN a }i-—~— OR BATTERY ———~ a asking you for larger monthly payments, and mak- j -_ payment terms harder for you to meet, we are offering you our new model Santa Fe Special, no advance in price, no money down, easier terms and smaller monthly payments. WE realize the war is

over and in order to double our business we MUST give you pre war inducements, better prices, easier terms and smaller payments. @ CONCEALED WIRING~_7 | Adjusted to Positions R POINT SWITCHES n be LOOK Adjusted to Temperature ” an

Adjusted to Isochronism

nds, Adjusted to the Second SS __ Thin Medel. All Sizes io vow tana toe ee ee Diagram of quadruple switch block showing one picture mire, to approve, a real masterpiece in watch crea- hundreds of possible “combinations tion. A Watch which passes the most rigid inspec- nt and tion and measures * to the exacting requirements of . " 4 A - h con- the great Santa Fe Railway System, and other great cious closing of radio or experimental cir- ‘ ‘ uits it is, therefore, quite sati A frame, Page 12 of our Watch Book is of . F ee reir phe ar: ange ndt by Special Interest to You CUE SUNRNS OF. Spee Pewee Sen ate N ted on a suitable base. Various con- pred a much Ask for our Watch Book free—then select the Watch moun ’ ‘ as he is today is that you would like to see, either the famous Santa Fe nections can be made between the switches, Special or the 6 position Bunn Special, and let us e e artist's : explain our easy payment plan and send the watch the one shown being simple and easy to express pre or you to examine. °o on wn. E ° wr Persie Rememb r—No money flown easy payments buys a remember. Number the four switches ome ay : master timepiece—a 21 Je uaranteed for a me * out all ot about belt the price you my for a similar watch A, B, C, D, and number the points 1 to A. e A per- of other makes. No money down—a wonder offer. Point 2-B connects with a concealed wire a i little bu ae off cone re WATCH COMPANY running to the circuit; the switch arm of B g ' omas } opeka sas ; ; ° + ariety, pe eperaes yap connects with point I-A; that pointesanecte |/48 going to get you— lf and Letter, Post Card or ‘this Peupee Will Bring ith th : pA C: th é it +2 of C ts My Beautiful Free Watch Book wit € point o-U; the switec connec Germs are here, there and everywhere. They are in . SANTA FE WATCH CO. with point 4-D; and switch D-4 connects the air, in your food and the very water you drink. In glazier 980 Thomas Bldg., Topeka, Kansas ° ° ° ° fact, scientists say your body is full of them. They are an free » ° with the other concealed wire of the circuit. only waiting for your vitality to weaken and then they lease send me your New Watch Book with the ° ra ° are going to get you. / 16 in —_— that this request does not obligate me The combination thus is A-1, B-2, C-3 net x t does a strong, healthy man care about au ° : * this? t te y reath- . glass and D-4. The number of switches used can ing deep with oxygen and pour heat pumiging fich, red Datine Name......-+.. eb iacs oR oem PRG Nis cle bbe e eee ste be reduced or increased.—B. F. D. blood, they are going to run for their lives. (A disease ’ er n as t u a! a has in a spider's web. | then . ° ide Tire Rim Forms Manhole Collar Food Was Meant to Eat. caren HEN a ore ri rom : — : r enjey ’ 2 i th rpose. ‘ood t to eat and a id the manhole is healthy ‘man has no regrets for satisfying his keen ap- j i = stite. man who roper exercise craves before Make $75.00 to $100.00 a required in con food and must have it. Water was meant to bathe ‘ week taking orders for AUTO- ‘ M oe By inti a drum- FIZIK, guaranteed carbon re- ciete work,. a with—both inside and out. By drin plenty r mover uick sales. big prof- . water you remove the waste matter wit! in, just as its, —- repeat ‘business. steel auto rim = MD washing your skin removes the waste matter without. pletion often can be used I MAKE MUSCLE EASY NEW METHOD as a collar. This was done in one instance ~ i y AUTO-FIZIK j i I t a doctor—I don’t claim t disease - for RSS fimoly on replace spark when three manholes were required m an That. is .: a Cw on a job. “But follow pgs Bm, and ; ph tart engine and in 30 alley adjacent to a garage. When the con- the doctor will starve to death waiting for you to take carbon is gone. ° ° sick. I build strength and endurance. I make muscle. * Cash in on this opportunity now to make crete was ready for pouring, three rims Follow my instructions and you will increase your arm ° r on n thirty 8——yes, an ut two inches on or po Toes ae mply ey postman $1.30 ond few were taken from the scrapheap and used as your chest in the same length of time.” hy ae 5 oniy. ee 7 n and sprayer. ; ey a starter. eanwhile, I work o ose in: ; te Glouey refanted f dissatished. ' Big profit shown, the beads forming @ secure anchor surrounding your heart and other vital organs which is tO agent offer included with your first order. age.—DALE R. VAN Horn. affect your entire physical being. You will soon feel h Write today to the thrill of life pulsing through your veins. You will eac UTO-FIZIK COMPANY have pep in your old backbone. There will be a flash arti St Dept. 101 Peoria Um iH to yout eve, _— a — to yous ay — — fan -? . ’ » ante . italit vi e strong robus ui over, = Buried Tank Keeps Reservoir I don’t promise these things-—1 guarantee them. peomne e me prove it. at is wha . use ZE Water Cool for Drinking Y'know I can do it. el ee at oe - == HEN i ss Send for My New 64-Page Book a home or factory is provided ” ZF We Pay $7 a Day : ; : ‘‘Muscular Development - with a roof tank or water reservoir Wonderful invention. The SERE- | mounted so that it is exposed to the heat ot ee ee winning pupils ? av: does more mac cost- in 20 times Ita price. Orders taken of the sun, the heat often a ana water uae Some of these came tome os pial weaidings, ol beg > ver & thousand @ | insipi i Ww rou will 1 | at their nt ues. book week—making from $7 to $21.0 day, | insipid to drink and too warm for a cool | | you will marvel at their present physiques. | This book Big demand. Easily carried with you | shower bath. A good method for cooling it will thrill you through and through. All I ask is ten ° anywhere. Built in just like a suit- . cents to cover the cost of wrapp' and mailing and it ips of case. Fully guaranteed. Low . | without the use of is yours to keep. | This will n not obligate you at all, but : ; ! the sake of your future al D ss, do no’ ; close Easy toTakeOrders ice is to draw off wat it off. Send today—right now, before you turn No collecting. Pay you . every day. the water through this page. forge a | | Sen eee EARLE E. LIEDERMAN 10-in. PERRY-LUDLOW CO., S.647 DAYTON, O. | 50 gals. capacity, Dept. 1300. 306 Broadway New York City The basement floor. Po EARLE E. LIEDERMAN take Easy Now to Make and $ 00 The water that _ Dept. 1309 Broadway, New York City i ° ° e i i - Dear Sir:—I enclose herewith 10 cents for which you AUR, Repair Electrical Appliances. * |} — | les in the under are (o send me, sithout any Gbligation on my Dart what: G ° Ni hr Wi <4 ground tank is fre- over a er. = oes — Spe Develop- § 4 enuine ne ome Paice a P # quently as much as S) ; ment. : print plainly. | This resistance wire business e! standard electri 72 g - iced appliance. 27 feet guaranteed up to 660 watts, 110—120 15 degrees cooler gE Yt, Be \'¢ NAMIE... 000. 6 aero 8 ING CTC RECSTUURS D CONS UO RI | for ita, 6 amps. th this you can make or repair yourown | than that stored in “Yt, , | 1 electrical ranges, furnaces, sadirons, toasters, irons, ° S cramer Sey ee ae ae q wafiie griddies, etc. Co i thcopperand mica | the reservoir on ST copeycmcmbdee aver gun tonal soaliiinnil nuts, screws, and full instructions sent prepaid for | +14 roof —G. A.V The water ip aeoled Ans an 4 - es | One * order C. O. D. and- Ytew- -extra , foe eat Vy unde: sp peeenepecessossepecreeeue «STATE. ...+++ aere — las LIED FACTORIES CORPORATION, 1007 |” a Ls ; 5 a Bidg., Kansas City, Mo. sc tinety maprieainn went Cetabe tinn ahaa biennial tb catia

The Home Workshop Department of Popular Science Monthly 117

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tear Soe NNR mn SA CTE a TEE 4 wats Diicdcheactote ba a mee mo oy oan Rn ee AEH Li intntl ine an ovoner See tage Net ae a eR I~ age SE A RR, Meta Pe ihe és ae fe Li 2 . 116 “I Knew You'd Make Good” “T ALWAYS felt you had it in you to get ahead. But for a time I was afraid “ontaed natural ability would be wasted ecause you had never trained yourself to do any one thing well. “But the minute you decided to study in your spare time I knew you’d make good. You seemed more ambitious—more cheerful—more confident of the future. I knew your employers couldn’t help but notice the difference in your work. “Think what this last promotion means! More money—more comforts—more of everything worth while. Tom, those hours you spent on that I. C. S. course were the best investment you ever made.” Ho about you? Are you always going to work for a small salary? Are you going to waste your natural ability all your life? Or are you going to get ahead in a big way? It all depends op what you do with your spare time. ) Oppertunity knocks—this time in the form of that familiar I. C. S. coupon. It may seem like a little thing, but it has been the means of bringing better jobs and bigger salaries to thousands of men. Mark and mail it today and without cost or obliga- tion, learn what the I. C. S. can do for you. ~ INTERNATIONAL CORRESPONDENCE SCHOOLS _ Box 7663-C, Scranton, Penna. Without cost or obligation on my part, please tell me how I can qualify for the position or in the subject before which I have marked an X: BUSINESS TRAINING COURSES Salesmanship aoe Stenography and Typing Business English Civil Service Railway Mail Clerk Common School Subjects High School Subjects O French Illustrating TECHNICAL AND INDUSTRIAL COURSES Engineering Architect Blue Print Reading Contractor and Builder Architectural Draftsman Concrete Builder Structural Engineer stry © Pharmacy Automobile Work Law C.P.A.) Accounting Airplane Engines Agriculture and Poultry OD Radio Mathematics Name reseepesseres Street 3-27-23 City State International Correspondence Schools Canadian, Limited, Montreal, Canada, HAIR GROWS! When our Vacuum Cap is used a few minutes daily. Senc on 60 days* FREE trial at our expense. Stops falling hair and dandruff. Science combined with common sense. Nu drugs or electricty. A postal brings illustrated booklet. Modern Vacuum Cap Co. 400 Barclay Denver, Colo. [SPORT BODIES tr FORD and CHEV. «0 at SG.00 | Life-size 3g P peper pat. UNDER bas boil SLUNG PARTS Per Set 472 The Shipshape Home How to Do the Odd Jobs CONFIDENCE is needed in driving nails. Grasp the han- dle firmly and strike with precision, espe- cially if you would rather not strike the wrong nail—the one on your finger. A good hammer is properly balanced and has a handle precisely the right length. Do not grasp it in the middle but at or near the end. For delicate work, when you need How to Drive a Nail | particularly good control, let your index CS one . ee /| W i finger and thumb reach up the handle. This gives a more flexible grasp. Start the nail with a good blow, not a timid one, and make the hammer swings short and snappy. They should be jolts; far-reaching swings are not necessary. See that the face of your hammer is clean. More bruised fingers come from a hammer in poor condition than from any other cause. Before using your hammer, rub it on a board, on the earth, or, if in very bad shape, on fine sandpaper. If the hammer has no hole in the end of the handle for soap or wax, bore a \4-in. hole about \% in. deep and keep it filled with soap. When using finishing nails in hard wood, dip the point of each nail in soap. It will surprise you how much easier the nail can be driven.—A. E. ELLING. WHENEVER possible, drill holes before nail- ing, especially if the joint is*to be subjected to much strain. The holes should be 1/32 to 1/16 in. smaller in diameter than the nails that are to be used. Nails driven into these holes will have, according to the Forest Products Labora- tory of the United States Forest Service, considerably more resistance both to direct pull and to sheer than nails driven directly into the wood. Ce- ment coated nails have holding qual- ities superior. to ordinary nails. In general, the length of nails should be somewhat more than twice the thickness of the first piece into which they are driven (Fig.1). If the nails are driven slightly on the slant, or “‘toe- nailed” (Fig. 2), they hold better.—L. P. F. Making Nails Hold Tea Oe Eee Home Workshop Department of Popular Science Monthly Law Course in Book Form 13 Vols. Bound in Law Buckram. Com 56 of America’s Most Eminent Legal Aeon Here is a complete home-study law course in book form that you can master in your spare time, Thirteen volumes, nearly 6,000 pages (7x 10 inches), bound in law buckram, red and black labels with titles in gold. This wonderful law course is the combined work of professors of Harvard, Yale, Pennsylvania, Michigan and Wisconsin law schools, Study at Home, Aided by Free Reading Course Every principle of law is made clear. Fascinati reading course of 25 Texts (free with the books a teacher, right at your elbow! A set of review question covers > text —- fully. ou get the entire 13-vol 75¢ a Week library and Complete Reaaaw Course of 25 pamphlets for only 75 cents a week, See offer in coupo ES cen) fei sar phere MAIL THE COUPON — = = == American Technical Society, Dept. L-620, Chicago, U.S.A. Please send “‘Library of American Law and Practice” and Reading Course for seven days’ examination, shippi charges collect. I will send 62.80 within seven days and 43.06 a month thereafter until I have paid $49.80 or return the books at your expense, Name Address Employed by You, Too, Can Play the HAWAIIAN GUITAR Just as the Natives Do— After Your FIRST LESSON You Will Play “‘ALOHA’’. We Guarantee That— Our method is so simple, interesting and appealing that you begin in your first lesson to learn the f lk Song ‘* HA’’, Think how happy you will be when you surprise your friends by playing the fascinating Hawaiian Guitar just as the natives dol Only Four Motions— und You Master Them Quickly ! In a few minutes you ecquine four motions pe the necessary to play Picdulicarase: cmsenonee teenie PO tc on tt note in your life--if ew A slightest knowledge of music, we can Guickiy and positively tench you , i é to play th wonderrully popalar inatramen er’ wi =e be center Just Mail a Post Card for ABeautifu!l Hawatian Guitar Special arrange- ments for lessonsif ir own lgwatian Guitar. How To Make > Things Electrical Have the fun of doing it yourself and save half the cost 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, $2.25 post paid POPULAR SCIENCE MONTHLY 225 West 39th Street, New York City Finest bicycle built —44 ¢' colors and sizes. Factory to Rider Bee. FREE delivery,express prepaid on Days Free Trial.Cash or easy pay’ts. RES lamps, wheels and equipment § ‘Write today for big catslor, money. . special Factory Prices, free trial plan and marvelous offers,

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Fascina 1e books) + igs t of review volume law e Reading ats a week, The Home Workshop Department of Popular Science Monthly 117 How to Build Plank-Faced Front Doors Inexpensively By Edwin M. Love pages T doors of the plank-faced variety, so popular in many Spanish and some English type houses, are usually sufficiently expensive to bar their use in homes of moderate cost. A southern California con- tractor, however, uses a method of building them for less than half the cost of millmade doors. The core consists of an o. .inary 13¢-in. | five-paneled stock door, which can be bought in his locality for about $3.75. A second-hand door will do, if the joints aresound. This . door is about 1% in. narrow- er than the opening, so that . strips . of wood of the kind to be used on the inside of the door can be glued to each edge. Strips of %- in. stock of various widths are nailed lengthwise on the door, as shown, after the face edges have been chamfered to form the V grooves in imitation of planks. If a window opening is desired in the door, a portion of one of the cross panels is cut out and a suitable frame inserted for the glass and grill, which are-held with molding. The construction can be somewhat im- proved by gluing as well as nailing the face veneer, and in using tongu and groove stoek to reduce the danger of water working through the joints when the door shrinks. Another method is to rabbet the stock, making the under rabbet about 14 in: Imitation planks veneered on a cheap stock door |. wider than the upper, so as to form a U- | shaped groove between the boards. Home Workshop _ Features that Will Save You Time and Money EATURES of unusual value to the home worker are scheduled for October. Another remarkably efficient radio set, built in our own ex- perimental workshop, will be described by Joseph Calcaterra. It is a receiver of the reflex type, embodying the principles of design described in this issue by Jack Binns. For the man or boy who has had little experience in wood- work, there will be an article, “Useful Tables Made without Mortised or Doweled Joints.” The new and valuable fea- ture, “Home Workshop Chem- istry,” which begins this month, will be continued with practical suggestions on the use of glues and cements. There will be the usual great | variety of articles for the more advanced workers. Mr. GEORGE H. BARROTT Box 313, Shelburne Falls, Mass. Mr. Cias. E. Bown 414 Oxford Ave., Dayton, Ohio Mr. VERNON W. J. CoFrFIN 174 Drayton Ave., Toronto, Can. “Mr. Ernest GRAY 173 East 3d North, Logan, Utah Mr. FRANKLIN HoRNE Box 505, Manitou, Colo. Mr. A. J. McCormack 294 Elmdorf Ave., Rochester,N.Y. Mr. R. J. NELSON Hopkins, Minn. Mr. C.H. Rice, c.o. En’gn’g. Dept. Olds Motor Wks., Lansing, Mich. Mr. Paut F. Stine 520 2d Ave. E., Twin Falls, Idaho Mr. Scott M. SAWYER Glenwood, Minn. Mr. H. M. TAytor 17 Caithness Ave., Toronto, Can. der a bushel.” useful metal. tive genius—or maybe just your “g edged.) . ““Every day lost is lost.’’ Address THESE MEN WON—WHY NOT YOU? The following IDEAS for Pressed Metal Articles, heretofore made of other materials, have already been purchased from readers of these advertisements who have taken ad- vantage of the opportunity to cash in on their abilities. The Engineering Advisory Board of Pressed Metal T. E. C. reports on Ideas thus far approved, accepted and paid for, as follows: (All the above winners submitted their suggestions as per instructions in the Pressed Metal Booklet. Have you a copy?) No longer need’ your mechanical cleverness remain “hidden un- It seems that almost everybody is suddenly (and most intelligently) interested in PRESSED METAL, Why can_ not. you suggest some new way to utilize its practically unlimited usefulness and economy? The ideas we buy become a public benefit. Just remember that Pressed Metal is anything that can be pro- duced by stamping from sheets of steel, brass, aluminum, copper, or any other The FREE Pressed Metal Booklet Tells HOW TO CAPITALIZE YOUR MECHANICAL TALENT OR INVEN- ood old common sense.” conditions and the amounts to be paid for the successful ideas, and also how to protect your- self against misappropriation of your creative thoughts by others. WRITE post card will do, but please make it easily legible so it can be properly filed and acknowl- PRESSED METAL Extexsion COUNCIL 27 QUINCY STREET, SUITE 1702, CHICAGO Mr. W. C. WiLson 924 W. Maple St., Johnson City, Tenn. Mr. C. R. MuLiin 314 2d St., Watertown, S, Dak. Mr. Percy L. MANN Box 104, Grant, Mich. Mr. HERBERT WARREN R. R. No, 1, Delaware, Ohio Mr. RoBERT PETERKIN Freehola, New Jersey Mr. T. M. HuGcues 214 Lansing Ave., Lynchburg, Va. Mr. WILLIAM BAKER 1302 Dallas Ave., Houston, Tex, Mr. THomas Gossack Big Run, Pa. Mr. S. E. Turk, 953 Mound St., Milwaukee, Wis. Mr. H. B. NEwTon 999 Sonoma Av., Santa Rosa, Calif. 4. It tells all the ODAY. (A $25.00 in PRIZE See top of page 4 in front of book for details Agents- It’s easy to make $16 so $35 ner Gey selling unique Knife and Sharpener. Eve! aoe p= the minute sees it. ® Not a G5: hetstone—| luces keen cutting edge as La A ceenes income, all or part time. (Sample, 50c. postpaid PREMIER MFG. Co.; Dept. 4, Detroit, Mich- eee ee) CHARGE YOUR BATTERY (RADIO or AUTO) end forcomplete Catalog of Auto of Auto Bois, Ac- Ac- i Fower Eauipment. AMERICAN TOP AND BODY CO. Lee St. Delphi nd.

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08: Sehr et sink Ue g l dies: ated [ 5 1 = & 18 AGENTS Popular Science Monthly With and Without Cars Make $100 @ to $250 A Week! fF YOU are making less than $100 a week send for our offer and change your luck! SAAL Agents are no smarter, work no harder than others, but they get the big money! machinery can be lubricated better with HEAVY OIL. Grease, grease cups, greasing systems are now out of date. Biggest opportunity in 10 it years—get in on quick! SAAL FREE OUTFIT for Agents “ We send ou abso- lutely free a complete $8.50 or $5 Saal Outfit for your own car, or a sample to carry. We help you succeed. 6 factories and $2,500,000.00 in resources back you to win! Coupon brings com- fe information— all it TODAY. SO pig pve a agate Magda H. G. SAAL CO., Dept. 506 i 1800 Montrose Ave., Chicago If the money-making opportunity is as big as you claim, I am interested in getting the facts J so I can get a share of the profits selling SAAL SYSTEMS. Without obligation send me com- plete information. St. No. or R.F.D.... eee ee eee eee eee eee eee CEs cecedbcnwesccbocsdves GUM .oo0e Every auto, truck, tractor—every piece of Get into a Business of your own! Get out of the small pay class. Be a success in life. We'll show you how to turn your time into $5000 to $15000 profits a year. Nothing to buy, no investment, no risk. No delivery or collecting And you get your share in cash every day! Heavy Oil System 100° Chassis Lubrication Heavy Oil, shot with a ton of force into steering, shackles and all chassis bearings, “‘makes cars ride better and last long>r.”” Owners find SAAL Lubrication the cheapest insurance against depreciation and repair bills. Saal System costs about half the price of old-type grease Systems. Free trial offer gets 9 sales out of 10 calls. 2000 Ibs. Hydraulic Pressure SAAL Heavy Oil System consists of “OIL SHOOTER" of simple, but patented design, which transforms the push of your hand on the plunger into 2000 Ibs. of hydraulic pressure. 42 fittings are supplied, more than enough for any car. Screw out grease cups, screw in fittings. No mechanic needed. HOLSTER supplied to carry OIL SHOOTER under hood, convenient to use. Motorists actually use SAAL lubrica- tion because “‘it’s a white collar job with service station results. And Now GENERAL MOTORS! SAAL Heavy Oil System adopted as regular ag oe by Oakland Division of General Motors Corporation, Velie, Durant, Chandler, Apperson, Case and many other manufacturers of high grade cars. And the truck fleets of such concerns as Standard Oil Co., of Indiana, Western Electric Co., etc., are now SAAL equipped. H. G. SAAL C0., “2v.cs° 23 Years Dept. 506, 1800 Montrose Ave., CHICAGO. ILL. HE pleasure of your outings will be increased vastly by a pair of powerful American-made binoculars; as fine as money can buy. For your home, your country club, or your vacation. them at your dealers. Bausch & Lomb BINOCULARS Bausch & Lomb Telescopes are also invaluable at home, See Booklet on request. Stereo-Prism country club or seashore. Bausch & Lomb Optical Co. New York Washington Chicago San Francisco London Rochester, New York In This Issue Editorial Insulin—A Miracle of Science By Donald Harris Airplane Conquers Fire Peril The Proofs of Evolution Article 7 in the series, ‘The Story of Man and His World,” by E. E. Free, Ph.D. New Steam Car Starts in 30 Seconds Rubber Silencer Prevents Hood Rattle Auto Drives [tself across Lake “How My Car Serves Me” A Prize Contest Announcement New Instrument Tests Gear Teeth Taking on Gas at High Speed Diameters of Distant Stars Measured Portable ‘‘Jack’’ Scale Weighs Locomotive Old Razor Blade Used as Scraper Handy Pocket Toilet Outfit Water Bicycling Is Newest Sport Ingenious Creel Strap Quickly Adjusted New Open Grate Burns Its Own Smoke Exhaust Gas, a Lurking Assassin By Raymond J. Brown Pontoons Raise Wreck from Sea The Science of Fire Fighting LOOMED POMS TOR SUBIC... so occ ccis's cdiacanna Non-Drip Coffee Strainer High Speed Telegraph Code Invented Safety Curb for Dangerous Curve. Door Guard Protects Housewife New Cold Patch Repairs Tires Motorized Prune Picker Giant Merry-Go-Round Wind Motor Filling an Ice Box Scientifically. , Light-Bulb Shield Prevents Shadows Safety Shield Protects Door Lock Closed Auto Body of Chicken Wire By Robert E. Martin Inverted Comet Adds Fuel to Sun Wild Birds Studied by Tags By Manus McFadden Revolving Lamp Shade Advertisement Airplane Picks Messages from Ground. Baby’s Bathtub Folds into Cradle. Building Wrecked by Rainfall Illuminated Bonnet Shaped like Dome. Riding *‘Race Horses’’ on Monorail Bell Pull Switches on Lights Centrifugal Tool Grinds Cylinders Ancient Indian Workshop Found Metal Erasing Shield for Typists Radig and Phonograph in Lamp €o0mpact Auto Kitchenette “Machine Gun” Type Duplicator Portable Factory Elevator Fighting Plane Has Novel Design. One-Man Bus Has Periscope A Clean Shave in the Dark Air Cushion Used in Shock Absorber Surveyor Maps as He Goes. Spring Guard for Punch Press Blindness Lurks in the Teeth By Edwin F. Bowers, M. D. Model Operating Room for Animals Reviving Frontier Days Anti-Friction Roller Bearing Knockdown Wheel for Tire Changing Typewriter Carbon Handled Automatically .... Toothed Vise Jaws Hold Round Stock Canoe Carrier Becomes Back Rest Interesting People and Their Work Mechanical Kinks of Tennis By William H. Keats Roller Skate Sailing Fishing Boat from Odds and Ends. World’s Largest Bass Drum Pocket Movie Camera. Aerial Camera Takes 10-Mile Picture... New Active Volcano Found Endless Tread Auto Paper Tees for Golf Practice School Boy Graduated. by Wireless Terraced Apartment H Bucking Auto [mitates Broncho Bird Gives Concerts by Radio World’s Most Powerful Machine Gun The Power of Auto-Suggestion, By James J. Walsh, Ph.D. Torsion Machine Tests Wooden Beams Voices Trained by Breath Recorder Living Human Cells Dissected. Phonograph Silencer Filters Scratches Uncle Sam Tags Fishes Galloping Hobby Horse Kettles Made from Pennies Rubber Masks for Actors A Storehouse of Inventors’ Ideas. . : Radio Champion Hears 35 Stations Auto “Squirrel Cage,’’ New Thriller Most Powerful Broadcasting Station ,Radio Fan Installs $5000 Ovtfit ‘Plain Teacups Serve as Amplifiers,. Loudspeaker Outfit for Recruiting Around the Radio Circuits By Jack Binns New Inventions for the Household Machine-Made Beauty to Order Repairing Electric Heating Appliances, Scale Weighs Carloads in Motion Machine Defines Character Winning Great Epsom Salts Deposit. The World’s Best Equipped A New Automatic Gear Shift. How to Buy a Car By Harold F. Blanchard New Aids to Car Comfort Hints on Repairing Your Auto . The Home Workshop .. . 75 Better Shop Methods... 80

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POPULAR SCIENCE MONTHLY

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POPULAR SCIENCE MONTHLY DENEVE COALS) vi = ~UVYA QW) BE These Bas-Relief Lincoln Book-Ends are of a heavy beautiful, bronzed metal; they would sefl in any store for at least $1.00; in most stores for $1.25 or $1.50. Read below how you may obtain a pair for nothing. Free—this pair of Lincoln Bas-Relief Book-Ends an offer that can never be made again An amazingly liberal introductory offer on a new set of thirty world’s masterpieces. Read below why it is made. "OU have heard of Little Leather Library books. There are few ood homes in the country where these beautiful little volumes cannot be found. -Over-20,000,000 were sold prior to 1923. Now, a new set of thirty of the world’s greatest masterpieces has been pub- lished in this edition at a price of only $2.98 for all thirty volumes. ; From past experience the publishers know that, as soon as this new set is fairly well distributed in representative Ameri- can homes, it will become as universally popular as their previous books. To have a few thousand sets distributed quickly, this unprecedented offer is made ‘to readers of Popular Science Monthly. Can you afford not to. take advantage of it? Here are thirty beautifully bound volumes, books that every intelligent person wants to own, sold at the amaz- ingly low price of only $2.98 for all thirty; and, in addition, this handsome pair of bronzed metal Lincoln Book-Ends, worth from $1.00 to $1.50, but given to you free. Thirty Books for the Price of One The books themselves are works that no person, mindful of his friends, would care to confess he is not familiar with. They are complete masterpieces, in some cases more than one, of such immortal authors as: Barrie Kipling Shaw 4 Allen Balzac Browning Dumas Emerson Whitman $5000.% in Cash Prizes T° FURTHER acquaint the public with the contents of these wonderful masterpieces, a unique prize. contest has been inaugurated and is now going on. There are 47 cash prizes, from $2500down. Complete details, if desired, will be mailed free upon request. The judges are Charles Dana Gibson, artist and president of Life; Professor Albert * Bushnell Hart, Harvard University; Wm. D. Moffat, editor of The Mentor. Contest Closes Oct. 31, 1923 Whittier Turgenev E. Browning Moore Poe Tennyson Irving Plato Longfellow Ibsen Wilde | Dante Shakespeare Maeterlinck Elbert Hub- Lamb Yeats bard Is this offer too good to be true? There are over 3000 pages in this set of books. They are in a very convenient pocket size, so that you can read them, not only at home, but in idle moments while traveling. The paper is equal in quality to that used in the ordinary $2.00 volume; the type is clear and easy to read; the binding is NOT paper, NOT cardboard, but a_ beautiful limp de luxe material, more durable than leather, and so handsomely embossed that even experts have mistaken it for hand-tooled leather. . How can thirty such books be sold for only $2.98? How is it possible? The fact is that the chief difficulty the publishers have POPULAR SCIENCE MONTHLY | — > > omens ss oa experienced is the belief that such an offer is ‘‘too good to be true’’—that there must be a “‘catch’’ somewhere. Even when peo- ple see the books they write and exclaim: “How can you do it?’’ “It is the most amaz- . ing bargain of my life.” ‘‘Each volume, I would have guessed, was worth at least $2.00." And so on. It is no secret, however, how this extra- ordinary value can be given. These books are printed in editions of at least one million copies at a time. Quantity production— and eliminating middlemen’s profits—that is the answer. Send no money—sent for free examination Sooner or later, you will want to obtain and read—or re-read, these great master- pieces of literature. Why, then, not order the set at once, when you can get this pair of Lincoln beok-ends free, and while the $5000 Prize Contest is going on? If you question the unprecedented value, remember that these entire thirty volumes will be sent for examination at our risk. Do not send any money. Simply. mail the coupon below. When the package arrives give the postman only $2.98, plus the few pennies for delivery charges. Then ex- amine the set at your leisure. If you do not agree that this is one of the most wonderful bargains of your life, send the set back any time within thirty days and your money will instantly be refunded. Can a fairer offer be made? References: Popular Science Monthly or Manufacturers Trust Co. of New York. Little Leather Library Corporation Dept. 6610 354 Fourth Avenue, New York, N. Y. / ¢ ¢ ¢ Little a Leather Li Corp’ 25 _- - a yy Som aa

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October, 1923; Vol. 103, No. 4. 25 cents a Copy; $2.50 a Year CIENCE and thought are inseparable twins. Each new discovery, each new in- vention, has the magic power of thought behind it. But an even more wonderful and more potent force is forethought. Fore- thought drives science forward to new achievements. It is forethought that per- mits the scientist to peer into the future, to look over the edge of the present and to see the needs of coming generations. * x * ULES VERNE was not a scientist, but he possessed the priceless gift of fore- thought. Fifty-four years ago, in ““Twenty Thousand Leagues under the Sea,” he fabricated a vivid picture of the modern submarine. Twenty-nine years later he prophesied that the United States would “have mighty navies, not only on the bosom of the Atlantic and Pacific, but in the upper air, and beneath the waters of the surface.” x * * Os as amazing as these predictions, both of which have been fulfilled, is the prophecy of Admiral Moffett, chief of aviation, United States Navy, on page 30 of this issue. He pictures an airship 900 feet long, equal to the Leviathan in size, carrying a fleet of airplanes as ocean steam- ers now carry lifeboats, manned by a regiment of men and capable of encircling the globe in a couple of days. When such monsters of the air are practicable, they will draw the ends of the earth closer together. Its peoples will be united in closer under- standing, and we may take week-end trips to foreign lands as we now drive into the country in our automobiles. * * * | PrORETHOUGHT and courage com- 4 bined in one man produced a scientist who has been called the “supreme bene- factor of the human race’’—Louis Pasteur. The dramatic life story of this great French- man is told on page 57. It was Pasteur who % Care Published in New York City at 225 West Thirty-ninth Street blazed the path on which .all modern sur- gery and medicine walks. He was jeered at, called an ignorant charlatan. But he per- severed and lived to see the scoffers at his feet. Millions are alive today who would be dead but for Pasteur. The whole world is this year observing the centenary of his birth and blessing his memory. * eT S OST of us, far from exercising fore- thought, do not use our brains enough even in the ordinary processes of thought. At least, that is the opinion which Dr. James J. Walsh, noted psychologist, ex- presses in a remarkable article on “Memory” on page 36. Doctor Walsh shows how, by the use of a simple ‘daily dozen’ for the . mind, all of us may strengthen our memories and make ourselves more efficient in carry- ing on the ordinary tasks of life. * * * RETHOUGHT of the sort that carries even science into the future is being displayed today by Capt. Donald Mac- Millan, famous Polar explorer, who has sailed into the illimitable spaces of the Far North. He plans to plant landmarks on the glaciers so scientists of the future may know exactly when the next Age of Ice is coming. In a thrilling article on page 48 Captain MacMillan tells how he will carry out this extraordinary scientific work and how he will attempt for the first time to make radio waves penetrate through the Northern Lights, broadcasting messages to us from the frozen Arctic. * * HE forethought of oil men and auto- mobile engineers has furnished us with protection from the odd but fearful fire hazard that tiny sparks of static electricity may bring to motorists. How this is done is told on page 27. In fact, every ‘article published in this number tells of discovered thi germ . See Table of Contents on page 127 pire saat who found . sible by the away of de- PopuLaR SCIENCE MONTHLY _a pew stroying them, who Issued monthly. Single copy, 25 cents. Canada $2.50; foreign countries, $3. The contents of this ma, ie & vieses, Yearly subscription to United States, its possessions, and Entered as second-class matter Dec. 28, 1918, at the Post Office at New York under the act of March 3,1879. Entered as second-class matter at the Post Office Department, Canada. Printed in U.S.A. Copyright, 1923, by the Modern Publishing Co. azine must not be reprinted without permission vesident; R. C.- Wilson, Vice-President B. Capen, Secretary and Treasurer er of fore- thought. POPULAR SCIENCE MONTHLY

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PROF. A. M. LOW, the “Edison of England,’ whose wonderful in- vention for photographing noise has been used successfully in the London underground railways. He is shown above watching the motor races at Brooklands, Eng., where the exhaust noises of the competing cars were measured by his device: “European scientists are on the eve of announcing one of the great- est discoveries of the age—flexible glass. I am confident that their ex- periments will prove successful within two years. Then we may possibly see the folding window- pane, the collapsible electric-light bulb and unbreakable dishes.” DR. ALES HRDLICKA, of the National Museum in Washington, D. C., and head of the American School for Prehistoric Studies in Europe, who is now directing a party of scientists visiting western Europe in search of prehistoric man: “It seems to be becoming more and more likely that man himself originated in western Europe. Archeological specimens represent- ing man’s _his- . : tory from the earliest part of the Ice Age and possibly before have been -re- covered in great numbers’ from this field. The museums of Paris, Brussels, London, and Prague are filled with them. But vast depos- its are still un- explored.” —————————

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mau 2 @ « iecoteinitemennieniiial DR. E. F. PHILLIPS, head of the bee station of the United States Department of Agriculture at Somer- set, Md., who has discovered many interesting new facts about bees: “The average bee, which weighs about 75 milligrams, will produce about seven times its weight in honey during its lifetime. Yet bees sometimes are lazy. Contrary to popular belief, the bee’s sting is essentially for protection against intruding stranger bees.” DEAN ALBERT C. EYCLESHYMER, of the College of Medicine, Uni- versity of Illinois: “The search for the ‘elixir of life’ is about at an end; yet in this chase after eternal youth, medical science has succeeded in prolonging life 16 years. Regularity, plain diet, and exercise are the basis of longevity. We should all live to be 100 years old.” —== Sir Joseph ‘Thecnton

Brief Bits of Timely Comment on the Sciences of the Hour ANDRE CITROEN, automobile manufacturer, known as “the Henry Ford of France” (at right), photographed with Henry Ford during the -Frenchman’s recent visit to America: “I think there is plenty of room for more cars in America. Americans like something new and they like it quick and good. I intend to build a factory in America soon and expect to be manufacturing cars there by Feb- ruary. I have found that American engineers can give me great help in improving the rate of output and solving problems to which French helpers are unused. I have picked in America some skilled men, the like of which I had not found before, and they are to help me in my French plants. I expect by their aid to triple the output of my factory.” SIR JOSEPH THOMSON, Brit- ish scientist and discoverer of the electron, who recently witnessed the progress of American engineers with his theory of electrons, and who now predicts that science will discover a new kind of water: “The discovery of a_ substance that would break down one of the hydrogen elec- trons in the water molecule would make pos- sible another kind of water. There is no rea- son why, with a strong enough agent, another | kind of water } -could not be dis- covered.” mn» >to am Lit. irr — © & « Lixs BGea mee «

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