dstone
excites a steady verticity in the whole iron (if the rod be not too long)
more vigorous throughout the whole mass in a shorter bar, and as long as
the iron remains touching the loadstone a little {125} stronger. But when
the iron is separated from contact with it, then it becomes much weaker,
especially in the end that was not touched. Just as a long rod, one end of
which is placed in the fire and heated, grows exceedingly hot at that end,
less so in the parts adjoining and in the middle, whilst at the other end
it can be held in the hand, and that end is only warm; so the magnetical
vigour diminishes from the excited end to the other end; but it is present
there instantly, and does not enter after an interval of time nor
successively, as the heat in the iron; for as soon as a piece of iron has
been touched by a loadstone it is excited throughout its whole length. For
the sake of experiment, let there be a rod of iron 4 or * 5 digits long,
untouched by a loadstone; as soon as you touch one end only with a
loadstone, the opposite end immediately, or in the twinkling of an eye, by
the power that it has conceived, repels or attracts a versorium, if it be
applied to it ever so quickly.

* * * * *

CHAP. IIII.

Why Iron touched by a Loadstone acquires an opposite
_verticity, and why iron touched by the true Northern side of a stone_
turns to the North of the earth, by the true Southern side
_to the South; and does not turn to the South when rubbed
by the Northern point of the stone, and when by
the Southern to the North, as all who have
written on the loadstone have
falsely supposed._

Demonstration has already been given that the northern part of a loadstone
does not attract the northern part of another stone, but the southern, and
repels the northern part of another stone from its northern side when it is
applied[203] to it. That general magnet, the terrestrial globe, disposes
iron touched by a loadstone in the same way, and likewise magnetick iron
stirs this same iron by its implanted strength, and excites motion and
controls it. For whether the comparison and experiment has been made
between loadstone and loadstone, or loadstone and iron, or iron and iron,
or the earth and loadstone, or the earth and iron conformed * by the earth
or strengthened by the power of a loadstone, the strength and inclinations
of each must mutually harmonize and accord in the same way. But the reason