the
18th, the 31st, and the 42nd. For if a loadstone or a piece of magnetick
iron, hanging in aequilibrium or floating on water, is attracted and
disposed toward certain definite points, when you bring above it a piece of
iron or another loadstone, it will not, if you afterward put the same[215]
below it, turn round to the contrary parts; but the same ends of the iron
or the loadstone will always be directed toward the same ends of the stone,
even if the loadstone or the iron is suspended in any way in aequilibrium
or is poised on a needle, so that it can turn round freely. He was deceived
by the irregular shape of some stone, or because he did not arrange the
experiment suitably. Wherefore he is led astray by a vain opinion, and
thinks he may infer that, just as a stone has an arctic and antarctic pole,
so also it has a western and an eastern, and an upper and a lower pole. So
from foolish ideas conceived and admitted arise other fallacies.

* * * * *

CHAP. XV.

The Poles, Aequator, Centre in an entire Loadstone
_remain and continue steady; by diminution and_
separation of some part they vary and
_acquire other positions._

[Illustration] *

Suppose A B to be a terrella, whose centre is E, and whose diameter (as
also its aequinoctial circle) is D F. If you cut off a portion (through the
arctic circle, for example), G H, it is demonstrable that the pole which
was at A now has a position at I. But the centre and the aequinoctial
recede toward B {145} merely so that they are always in the middle of the
mass that is left between the plane of the arctick circle G I H and the
antarctick pole B. Therefore the segment of the terrella comprised between
the plane of the former aequinoctial (that, of course, which was the
aequator before cutting that part away) D E F and the newly acquired
aequator M L N will always be equal to the half of that part which was cut
off, G I H A. [Illustration] * But if the portions have been taken away
from the side C D, the poles and axis will not be in the line A B, but in E
F, and the axis would be changed in the same proportion as the aequator in
the former figure. For those positions of forces and virtues, or rather
limits of the virtues, which are derived from the whole form, are moved
forward by change of quantity and shape; since all these limits arise from
the conspiring together of the whole and of all {146} the parts united; and
the verticity or t