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 199
nce-wheel above thehelices. As the wheelrevolves, the current isconveyed to each doublehelix in succession, bymeans of a break-pieceon its axis. This is sim-ilar in construction tothat described in <§> 187,jjjj^jlj^ except that the two^ ^ wires which press on the break-piece are connected… … HiuiiimflniMiiiiuTmmflnTtffliiyJiiMmtt
