[Illustration: FIG. 226.--A helix through which current flows always
points north and south, if it is free to rotate.]
_c_. If a coil conducting a current is held near a suspended magnet,
one end of the helix will be found to attract the north pole of the
magnet, while the opposite end will be found to repel the north pole
of the magnet. In fact, the helix will be found to behave in every
way as a magnet, with a north pole at one end and a south pole at the
other. If the current is sent through the helix in the opposite
direction, the north and south poles exchange places.
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