Twentieth century manual of railway and commercial telegraphy (1905)
Meyer, Frederic Louis, b. 1875 · Chicago, New York, Rand, McNally & Company · leaf 18
Fig. 5. Dry Battery. MANUAL OF TELEGRAPHY. Battery. 15 … Fig. 6. Gravity Battery. WTiat Kind of haltery is generally used in thetelegraph service—The gravity battery is generallyused for the production of an electric current whichdevelox)s by chemical action. Wliat are gravity batteries — Two fluid cells.Instead of employing a porous cell to keep the…
Telegraph
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