Theory and practice of the electric telegraph; a manual for operators and students (1875)
Churchill, Charles Henry, d. 1904. [from old catalog] · Oberlin, Ohio, Sherman & bros. · leaf 70
THE ELECTRIC TELEGRAPH. 49 ble to work the register is often ample for the lighter move-ment of the sounder. - 8. What is the box sounder? The box sounder is designed to give resonance to the soundof the lever. Its construction is like that of a relay exceptthat the magnet is enclosed in a fine… … Box Sounder, or Relay.9. Describe the pocket relay. In the pocket relay the lever is brought down so as to packIt is a main-line sounder and is used by line m a caserepairers. Fig. 36. rocket Relay,10. What is the switch: The switch, or commutator is a contrivance for quicklychanging the current…
Telegraph
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