An elementary book on electricity and magnetism and their applications (1919)
Jackson, Dugald C. (Dugald Caleb), 1865-1951, Jackson, John Price, b. 1868, Black, Newton Henry, b. 1874 · New York, The Macmillian Co · leaf 128
Samuel F. B. Morse (1791-1872J. An American artist and inventor, was born at Charlestown (now part of Boston),Massachusetts, was graduated at Yale College in 1810, and in 1832 inventedthe commercial telegraph and the dot-and-dash alphabet known by his name.In 1844 by the aid of a 830,000 grant from… … Fig. 61. — Telegraph relay. many turns of fine wire on their magnets. Thus they may besatisfactorily operated on as little current as eight or tenmilliamperes.* These in-struments are called relays(Fig. 61). Reading signals directlyfrom a relay is not usuallyattempted, as the motionof its armature…
Electricity · Magnetism
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