_c_. Poles of the same name repel each other; poles of unlike name
attract each other.
_d_. A magnet possesses the power of attracting certain substances,
like iron, and this power of attraction is not limited to the magnet
itself but extends into the region around the magnet.
308. Magnetic Properties of an Electric Current. If a
current-bearing wire is really equivalent in its magnetic powers to a
magnet, it must possess all of the characteristics mentioned in the
preceding Section. We saw in Section 296 that a coiled wire through
which current was flowing would attract iron filings at the two ends
of the helix. That a coil through which current flows possesses the
characteristics _a_, _b_, _c_, and _d_ of a magnet is shown as follows:--
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