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 249
Fig. 69.Hydraulic model, duplex telegraphy. … Plate Y Copyright l>y J. H. IPhiu C^ CtTHOMAS ALVA EDISON. FOUR MESSAGES ON ONE WIRE 213 ducing condensers as already described in Chapter XIV(Fig. 60). He thus perfectly balanced the electrostaticcharge of the line, and duplex telegraphy at once becamea commercial success for both land and…
Fire · Electricity · Color photography
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