Cumming, Linnæus, b. 1843. [from old catalog] · New York, D. Van Nostrand · leaf 309
age (Fig. 187, b) consisting of verticalwires pivoted on its middle, one half dipping into each halfof the mercury cup, will keep up a constant rotation, as iseasily seen by considering the motion of the conductor in thefield of magnetic force, traversed by a current in one half T 290 Electricity,… … Fig. 187. Sometimes the permanent magnet is replaced by an ex-ternal coil of wire to carry the current, and we have the innercoil rotating continuously. This we may explain either bythe electro-magnetic action of the two coils on each other, orby the attractions and repulsions of parallel and…
Electricity
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