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 132
mall plate of copper, c, and the otherto a similar plate of zinc, z. These plates are fast-ened to a small piece of wood, in order to keep themapart, and placed in a little glass cup, D. To putthe instrument in action, a sufficient quantity ofwater, acidulated by a few drops of sulphuric ornitric… … 116 DAVISS MANUAL. the polarity of the earth, like a compass needle. Thearrow indicates the course of the galvanic current inthe coil from the copper to the zinc. 186. Take a bar magnet, M, and, holding it hori-zontally, bring its north pole near to the south poleof the ring. The ring will move…
![An illustration from [Electric engineering.] (1902)](https://img.insideoutlibrary.com/img/200/ia-electricengineer01inte-19-1.webp)
