CHAP. XXI.
*
If Paper or any other Medium be interposed,
an armed loadstone raises no more than an
unarmed one.
bservation 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 cohæsion of the metal is hindered, nor are the metals cemented together at the same time by the operation of the magnet.
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.
f 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 clingsmore
