History, theory, and practice of the electric telegraph (1866)
Prescott, George B.(George Bartlett),1830-1894 · Boston, Ticknor and Fields · leaf 284
ious objection, that when a fracture occurs itcannot be discovered except by climbing the pole and making aminute examination (Fig. 79). We have under our charge sometwo hundred miles of line insulated in this manner, which hasbeen in operation about four years, and has required very little… … Fig. 78. Fig. 79. The white flint insulator (Fig. 80), invented by Mr. E. B. El-liott, we consider the best in use. The superiority of this insu-lator consists in its strength, insulating prop-erties, and economy. The claim for inven-tion is twofold : the anti-porous nature ofthe material — being…
Telegraph
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