St. John, Thomas M. (Thomas Matthew), b. 1865 · New York, T. M. St. John · leaf 170
Fig. 256. Fig. one form. Two eledlromagnets are shown, one beinggenerally joined to a white push-button for turning onthe gas and lighting it, the other being joined to a blackbutton which turns off the gas when it is pressed. Thearmatures of the magnets work the gas-valve. Sparksignite tlie gas,…
Electricity
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