Davis's manual of magnetism : including galvanism, magnetism, electro-magnetism, electro-dynamics, magneto-electricity, and thermo-electricity (1854)
Davis, Daniel · Boston : Palmer and Hall · leaf 204
ght is suspended from it, it may fall a very slightdistance, and be attracted again. The time requiredto destroy the previously existing polarity, and torenew it in the opposite direction, is exceedinglyshort. 298. Electro-Magnet, in Case. — An electro-magnet of considerable power is represented in… … the case are seen two screw-cups, for making con-nection with the battery. There are two strongrings, one attached to the bend of the magnet, andthe other to the armature. The magnet, with itscase, may be suspended by the former ring andweights hung from the latter. 299. Yery large electro-magnets…
