History, theory, and practice of the electric telegraph (1866)
Prescott, George B.(George Bartlett),1830-1894 · Boston, Ticknor and Fields · leaf 92
tains his name, andof which it appears thathe had conceived the ideaas far back as 1832. Itsprinciple is very simple.It requires but a singlecircuit; consequently buta single insulated wire,and the return by theearth. At the extremityof the circuit, where thedespatch is to be received,is an… … Fig. 32. 74 ELECTRIC TELEGRAPH APPARATUS. bar, called an armature, is attached to a brass lever sustained in ahorizontal position by two pivots. The soft iron armature isattached to one end of this lever, while the other end is armedwith a steel point, which is called a pen. Under the point of…
Telegraph
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