The telegraph in American and Morse memorial (1886)
Reid, James D · New York, Printed for the author by J. Polhemus · leaf 944
ore, the glass and wooden pin has become, par excel-lence, the American insulator. The umbrella watershedform has, to secure constant cleanness of surface, givenplace to straight vertical sides,\vhile the addition of a screwthread formed on the inside of the insulators fitted to asimilar thread on… … ■i>-^ 862 American Telegraphic History. ductors led to invention in another direction. A relay of high sensi-tiveness, which was another word for high resistance, was one of theearliest plans to render the wires effective. These accomplished littlepractical benefit. They worked splendidly in…
Morse, Samuel Finley Breese, 1791-1872 · Telegraph
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