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 69
ssing the registerenters the frame F which has a platinum point at P. Whenthe armature is attracted the local circuit is closed. A springwithdraws the armature when the line current is broken.Fig. 34. 7. what is the sounder? Xhe sounder is an instru- ment for reading a messageby the ear. It is an… … 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…
Telegraph
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