St. John, Thomas M. (Thomas Matthew), b. 1865 · New York, T. M. St. John · leaf 96
Fig. n8. THE ELECTRIC BELL AND SOME OE ITS USES. 93 … Fig. 119. many taps of the bell can be given as desired by pressing the push-button. Fig. 119 shows a gong for railway crossings, signals, etc. Fig. 120 shows a circuit including cell, push-button, and bell, with extra wire for lengthen-ing the line.Electro-Mechanical Gongs are used to give loud…
Electricity
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