*
That an armed Loadstone draws Iron no more than an
_unarmed one: And that an armed one is more strongly united_
to iron is shown by means of an armed loadstone
_and a polished cylinder of iron_.
If a cylinder be lying on a level surface, of too great a weight for an
unarmed loadstone to lift, and (a piece of paper being interposed) if the
pole of an armed loadstone be joined to the middle of it; if the cylinder
were drawn from there by the loadstone, it would follow rolling; but if no
medium were interposed, the cylinder would be drawn along firmly united
with the armed loadstone, and in no wise rolling. But if the same loadstone
be unarmed, it will draw the cylinder rolling with the same speed as the
armed loadstone with the paper between or when it was wrapped in paper.
Armed loadstones of diverse weights, of the same ore vigour * and form,
cling and hang to pieces of iron of a convenient size and proportionate
figure with an equal proportion of strength. The same is apparent in the
case of unarmed stones. A suitable piece * of iron being applied to the
lower part of a loadstone, which is * hanging from a magnetick body,
excites its vigour, so that the loadstone hangs on more firmly. For a
pendent loadstone clings {90} more firmly to a magnetick body joined to it
above with a hanging piece of iron added to it, than when lead or any other
non-magnetick body is hung on.
A loadstone, whether armed or unarmed, * joined by its proper pole to the
pole of another loadstone, armed or unarmed, makes the loadstone raise a
greater weight by the opposite end[177]. A piece of iron also applied to
the pole of a magnet produces the same result, namely, that the other pole
will carry a greater weight of iron; just as a loadstone with a piece of
iron superposed on it (as in this figure) holds up a piece of iron below,
which it cannot hold, if the upper one be removed. * Magneticks in
conjunction make one magnetick. Wherefore as the mass increases, the
magnetick vigour is also augmented.
An armed loadstone, as well as an unarmed * one, runs more readily to a
larger piece of iron and combines more firmly with a larger piece than with
a lesser one.
* * * * *