Which pole of the stone is the Boreal: & how it is
_distinguished from the austral_.
One pole of the earth turns toward the constellation of the Cynosure, and
constantly regards a fixed point in the heaven (except so far as it changes
by the fixed stars being shifted in longitude, which motion we recognize as
existing in the earth, as we shall hereafter prove): While the other pole
turns to the opposite face of heaven, unknown to the ancients, now visible
on long voyages, and adorned with multitudinous stars: In the same way the
loadstone has the property and power of directing itself North and South
(the earth herself consenting and contributing force thereto) according to
the conformation of nature, which arranges the movements of the stone
towards its native situation. Which thing is proved thus: Place a magnetick
stone (after finding the poles) in a round wooden vessel, a Bowl or dish,
at the same time place it together with the vessel (like a sailor in a
skiff) upon water in some large vessel or cistern, so that it may be able
to float freely in the middle, nor touch the edge of it, and where the air
is not disturbed by winds, which would thwart the natural movement of the
stone. Hereupon the stone placed as it were in a ship, in the middle of the
surface of the still and unruffled water, will at once put itself in motion
along with the vessel that carries it, and revolve circularly, until its
austral pole points to the north, and its boreal pole to the south. For it
reverts from the contrary position to the poles: and although by the first
too-vehement impulse it over-passes the poles; yet after returning again
and again, it rests at length at the poles, or at the meridian (unless
because of local reasons it is diverted some little from those points, or
from the meridional line, by some sort of variation[66], the cause of which
we will hereafter state). However often you move it away from its place, so
often by virtue of nature's noble dower does it seek again those sure and
{15} determined goals; and this is so, not only if the poles have been
disposed in the vessel evenly with the plane of the horizon, but also in
the case of one pole, whether austral or boreal, being raised in the vessel
ten, or twenty, or thirty, or fifty or eighty degrees, above * the plane of
the horizon, or lowered beneath it: Still you shall see the boreal part of
the stone seek the south, and the austral part seek the north; So much so
that if the pole of the stone shall be only one degree distant from the
Zenith and highest point of the heaven, in the case of a spherical stone,
the whole stone revolves until the pole occupies its own site; though not
in the absolutely direct line, it will yet tend toward those parts, and
come to rest in the meridian of the directive action. With a like impulse
too it is borne if the austral pole have been raised toward the upper
quarters, the same as if the Boreal had been exalted above the Horizon. But
it is always to be noted that, though there are various kinds of unlikeness
in the stones, and one loadstone may far surpass another in virtue and
efficiency; yet all hold to the same limits, and are borne toward the same
points. Further it is to be remembered * that all who before our time wrote
of the poles of the stone, and all the craftsmen and navigators, have been
very greatly in error in considering the part of the stone which tended to
the north as the north pole of the stone, and that which verged toward the
south, the south pole, which we shall hereafter prove to be false. So badly
hitherto hath the whole magnetick philosophy been cultivated, even as to
its foundation principles.
* * * * *