HOW ONE LODESTONE ATTRACTS ANOTHER
When you have discovered the north and the south pole in your lodestone,
mark them both carefully, so that by means of these indentations they
may be distinguished whenever necessary. Should you wish to see how one
lodestone attracts another, then, with two lodestones selected and
prepared as mentioned in the preceding chapter, proceed as follows:
Place one in its dish that it may float about as a sailor in a skiff,
and let its poles which have already been determined be equidistant from
the horizon, i. e., from the edge of the vessel. Taking the other stone
in your hand, approach its north pole to the south pole of the lodestone
floating in the vessel; the latter will follow the stone in your hand as
if longing to cling to it. If, conversely, you bring the south end of
the lodestone in your hand toward the north end of the floating
lodestone, the same phenomenon will occur; namely, the floating
lodestone will follow the one in your hand. Know then that this is the
law: the north pole of one lodestone attracts the south pole of another,
while the south pole attracts the north. Should you proceed otherwise
and bring the north pole of one near the north pole of another, the one
you hold in your hand will seem to put the floating one to flight. If
the south pole of one is brought near the south pole of another, the
same will happen. This is because the north pole of one seeks the south
pole of the other, and therefore repels the north pole. A proof of this
is that finally the north pole becomes united with the south pole.
Likewise if the south pole is stretched out towards the south pole of
the floating lodestone, you will observe the latter to be repelled,
which does not occur, as said before, when the north pole is extended
towards the south. Hence the silliness of certain persons is manifest,
who claim that just as scammony attracts jaundice on account of a
similarity between them, so one lodestone attracts another even more
strongly than it does iron, a fact which they suppose to be false
although really true as shown by experiment.