Henderson, C. Hanford (Charles Hanford), 1861-1941, Woodhull, John F. (John Francis), 1857-1941 · New York, D. Appleton and company · leaf 299
Fig. 188.—The telephone. … m and m. When these induced currents go in one direc-tion they strengthen the magnet, and when they go in theopposite direction they weaken the power of the magnet. ELECTRIC CURRENTS 277 This causes the disks of soft iron, R and R, to vibrateexactly as they would if one spoke directly against…
Physics
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