the north and south by magnetical motion, and
would settle at the same points at which they are now fixed. The reason why
the terrestrial globe seems to remain more steadily with the one pole
toward those parts and directed toward the Cynosure, and why its pole
diverges by 23 degrees 29 minutes, with a certain variation not
sufficiently investigated as yet by Astronomers, from the poles of the
ecliptick, depends on its virtue magnetical. The causes of the precession
of the aequinoxes and the progression of the fixed stars, and of the
change, moreover, in the declinations of the sun and of the tropicks, must
be sought from magnetick influences; so that neither that absurd motion of
trepidation of Thebit Bencora[197], which is at great variance with
observations, nor the monstrous superstructures of other heavens, are any
longer needed. A versatory iron turns to the position of the earth, and if
disturbed ever so often returns always to the same points. For in the far
regions of the north, in a latitude of 70 or 80 degrees (to which at the
milder seasons of the year our sailors are accustomed to penetrate without
injury from the cold); in the regions halfway between the poles; on the
aequator in the torrid zone; and again in all the maritime places and lands
of the south, in the highest latitude which has thus far been reached,
always the iron magnetick finds its way, and points to the poles in the
same manner (excepting for the difference of variation); on this side of
the aequator (where we live), and on the other side to the south, less well
known, but yet in some measure explored by sailors: and always the lily of
the compass points toward the North. This we have had confirmed by the most
eminent captains, and also by very many of the more intelligent sailors.
These facts have been pointed out to me and confirmed by our most
illustrious Sea-god, Francis Drake, and by another circumnavigator of the
globe, Thomas Candish; our terrella also indicates the same thing. This is
demonstrated in the case of the {118} [Illustration] orbicular stone, whose
poles are A and B; an iron wire CD, which is placed upon the stone, always
points directly along the meridian toward the poles AB, whether the centre
of the wire is on the central line or aequator of the stone, or on any
other part situated between the aequator and the poles, as at H, G, F, E.
So the cusp of a versorium on this side of the aequator points toward the
north; * on t