Tunzelmann, George William von, 1856- · New York, Scribner & Welford · leaf 248
not required; and also ELECTRIC LIGHTING. 227 for use in coal-mines containing explosive gases. In suchcases as these it would not always be convenient to havethe lamps attached to long wires leading to the sourceof current. Primary batteries might, of course, be used,and indeed they have been… … fc i
Electric industries · Electricity
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