History, theory, and practice of the electric telegraph (1866)
Prescott, George B.(George Bartlett),1830-1894 · Boston, Ticknor and Fields · leaf 512
tions are made through the sounder mag-nets R, R, the relay armature levers a, a, and screw-points b, b, inthe usual manner, and require no further explanation. The regularlocal batteries and connecting wires are omitted in the drawing forobvious reasons. The extra local magnets L, L act upon… … the relay magnets M, M< is done by them, instead of by springs, as inthe case of the other repeaters described. The repeater is shown in the cut with the eastern and western cir-42 494 THE PROGRESS OF THE ELECTRIC TELEGRAPH. cuits closed. The circuits of the extra local batteries B, B, shown…
Telegraph
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