Physical sciences
Free to read here, from Project Gutenberg.
The Master Key
On the Connexion of the Physical Sciences
The Boys' and Girls' Pliny
The Child's Book of Nature
Round-about Rambles in Lands of Fact and Fancy
Professor Johnny
Through Magic Glasses and Other Lectures
The Master Key
The Fairy-Land of Science
In Search of a Son
Rollo's Philosophy [Fire]
