nets armed cohaere firmly when duly joined, and accord into one; and
though the first be rather weak, yet the second one adhaeres to it not only
by the strength of the first, but of the second, which mutually give
helping hands; also to the second a third often adheres and in the case of
robust stones, a fourth to the third.

* * * * *

{89}

CHAP. XXI.

*

If Paper or any other Medium be interposed,
an armed loadstone raises no more than an
_unarmed one_.

Observation has shown above that an armed loadstone does not attract at a
greater distance than an unarmed one; yet raises iron in greater quantity,
if it is joined to and made continuous with the iron. But if Paper be
placed between, that intimate cohaesion of the metal is hindered, nor are
the metals cemented together at the same time by the operation of the
magnet.

* * * * *

[Illustration]

CHAP. XXII.

*

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, ar