Dodge, Mary Mapes, 1830-1905 · New York : Scribner · leaf 568
ich strikes the bell as the currentcauses the armature to vibrate. TELEGRAPH-KEY AND SOUNDER. Telegraph instruments are very simple tomake and two boys can easily have a line be-tween their homes. The key is simply a contact maker andbreaker, so that the circuit can be convenientlyand rapidly… … FIG. 28. A TELECRAIH-KEV. key to strike against. Two L pieces of metalare attached to the middle of the board to sup-port the key-bar by a bolt passing through themand the bar, and at the rear of the board an-other upholsterers tack is driven in the woodfor the end of the bar to strike and make a…
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