[Illustration: FIG. 225.--A south pole attracts a north pole.]
The main facts relative to magnets may be summed up as follows:--
_a_. A magnet points nearly north and south if it is allowed to swing
freely.
_b_. A magnet contains two unlike poles, one of which persistently
points north, and the other of which as persistently points south, if
allowed to swing freely.