History, theory, and practice of the electric telegraph (1866)
Prescott, George B.(George Bartlett),1830-1894 · Boston, Ticknor and Fields · leaf 510
ce, either of the relay lmagnet M or the extra localmagnet Z, when exerted uponthe lever, will have the effect ofclosing the regular local circuitconnected therewith. By tracing the extra local cir-cuit B, it will be seen that it isso arranged that the closing ofthe sounder R cuts off the cur-rent… … 492 THE PROGRESS OF THE ELECTRIC TELEGRAPH. western operator upon opening his key destroys the attraction inthe relay M, causing the sounder lever I to break the extra localcircuit at p, which then flows through the magnet L, while at thesame instant the lever I also breaks the eastern main circuit…
Telegraph
Internet Archive · Medical Heritage Library · Public Domain Mark 1.0. Free to use for anything.
![An illustration from [Electric engineering.] (1902)](https://img.insideoutlibrary.com/img/200/ia-electricengineer02inte-339-192.webp)