Cumming, Linnæus, b. 1843. [from old catalog] · New York, D. Van Nostrand · leaf 317
yers of gutta-percha and Chattertons compound(a mixture of tar, resin, and gutta-percha), which form theinsulator proper. Round the insulator is a layer of hemp, andround this again a protecting sheath of about ten or twelvesteel wires, each coated with hemp. Near the shore end thesheath of hemp… … 196. The Battery.—The battery most in use in thiscountry is some form of Daniells. They are fitted up in chap, v.] Electro- Magnetism and Dynamics. 299 troughs of about twenty cells, and will run for a considerabletime without further attention than filling up with water when
Electricity
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