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 252
o someof those strictly called electro-magnetic ; as in theinstrument represented in Fig. 162, which consistsof a circular coil of insulated wire, B, fitted to rotateon a vertical axis within a larger one. A, mountedon a brass pillar. The inner coil has a pole-changerfixed to its axis of motion for… … 236 DAVIS S MANUAL. Fig. 162.
