History, theory, and practice of the electric telegraph (1866)
Prescott, George B.(George Bartlett),1830-1894 · Boston, Ticknor and Fields · leaf 149
the figure before the poles of themagnet. This is held back by a delicate spiral spring, graduatedby a screw, which is also seen to the left. Above are two circu-lar plates of glass. The upright bar, armed with two littleknobs, to perform the part of a hammer, rises between theseplates. When the… … draws attention to the register. The duty of the operator is thento set the clock-work in motion, and receive the message commu-nicated. This instrumentcan be used also as a re-ceiving magnet, by pla-cing a platinum point onthe upright bar or pen-dulum, and a little plati-num disc immediately…
Telegraph
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![An illustration from [Electric engineering.] (1902)](https://img.insideoutlibrary.com/img/200/ia-electricengineer02inte-265-139.webp)
