Dodge, Mary Mapes, 1830-1905 · [New York : Scribner & Co.] · leaf 581
iption. You will understandit better, perhaps, if you experiment a little. Youcan easily make a pair for yourself, rude and im-perfect, it is true, but good enough for all the testsyou may want to apply. For each you will want: (i) a straight magnet;(2) a coil of silk-covered copper wire; (3) a… … BELL S TELEPHONE. of iron near it must vary in the same manner. The the ground. (Two wires between the instruments varying pull on the plate must make it move, and would make the ground-wires unnecessary, but this this movement must set the air against the plate in would use up too much wire.) The…
Children's literature
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