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 188
HELIACAL RING. in motion. The polarity of the helix bears so close aresemblance to that of a magnet, that it is usual to Fig. 110. … speak of it as magnetic, and to give the names ofnorth and south poles to the extremities of its axis. 274. In Fig. Ill are represented, at a a, twodouble cylinders of iron, enclosing a coil. A sec- Fig, 111.
