Flame, electricity and the camera; man's progress from the first kindling of fire to the wireless telegraph and the photography of color (1901)
Iles, George, 1852-1942 · New York, Doubleday & McClure co. · leaf 130
emselves in concentric curves instead of in radialHnes (Fig. 31). Sturgeon, in 1824, advanced matters by an importantstep as he discriminated between the magnetism of steeland that of soft iron. He noticed that soft iron was mag-netic only while in contact with a steel magnet; whenhe severed them… … Fig. 29. Electric solenoid pole (A) attracted by-dissimilar pole (B) of bar magnet.
Fire · Electricity · Color photography
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