1ed than thoſe of the Magnet, which are more groſſe, impure, and
rare. From whence it followeth, that the ſuperficies of two
rons that are to touch, by being exquiſitely plained, filed, and
burniſhed, do ſo exactly conjoyn, that all the infinite points of
the one meet with the infinite points of the other; ſo that the
filaments, if I may ſo ſay, that collegate the two Irons, are many
more than thoſe that collegate the Magnet to the Iron, by reaſon
that the ſubſtance of the Magnet is more porous, and leſſe
pact, which maketh that all the points and filaments of the
ſtone do not cloſe with that which it unites unto. In the next
place, that the ſubſtance of Iron (eſpecially the well refined, as
namely, the pureſt ſteel) is of parts much more denſe, ſubtil,
and pure than the matter of the Loadſtone, is ſeen, in that one
may bring its edge to an extraordinary ſharpneſſe, ſuch as is that
of the Raſor, which can never be in any great meaſure effected in
a piece of Magnet. Then, as for the impurity of the Magnet, and
its being mixed with other qualities of ſtone, it is firſt ſenſibly
diſcovered by the colour of ſome little ſpots, for the moſt part
white; and next by preſenting a needle to it, hanging in a
thread, which upon thoſe ſtonyneſſes cannot find repoſe, but
being attracted by the parts circumfuſed, ſeemeth to fly from
^{*} thoſe, and to leap upon the Magnet contiguous to them: and
as ſome of thoſe Heterogeneal parts are for their magnitude
ry viſible, ſo we may believe, that there are others, in great
bundance, which, for their ſmallneſſe, are imperceptible, that are
diſſeminated throughout the whole maſſe. That which I ſay,
(namely, that the multitude of contacts that are made between
Iron and Iron, is the cauſe of the ſo ſolid conjunction) is
firmed by an experiment, which is this, that if we preſent the
ſharpned point of a needle to the cap of a Magnet, it will ſtick
no faſter to it, than to the ſame ſtone unarmed: which can
proceed from no other cauſe, than from the equality of the
tacts that are both of one ſole point. But what then? Let a
^{*} Needle be taken and placed upon a Magnet, ſo that one of its
extremities hang ſomewhat over, and to that preſent a Nail; to
which the Needle will inſtantly cleave, inſomuch that
ing the Nail, the Needle will ſtand in ſuſpenſe, and with its two
ends touching the Magnet and the Iron; and withdrawing the
Nail yet a little further, the Needle will forſake the Magnet;
provided that the eye of the Needle be towards the Nail, and
the point towards the Magnet; but if the eye be towards the
Loadſtone, in withdrawing the Nail the Needle will cleave to
the Magnet; and this, in my judgment, for no other reaſon,
ſave onely that the Needle, by reaſon it is bigger towards the
eye, toucheth in much more points than its ſharp point doth.
rare. From whence it followeth, that the ſuperficies of two
rons that are to touch, by being exquiſitely plained, filed, and
burniſhed, do ſo exactly conjoyn, that all the infinite points of
the one meet with the infinite points of the other; ſo that the
filaments, if I may ſo ſay, that collegate the two Irons, are many
more than thoſe that collegate the Magnet to the Iron, by reaſon
that the ſubſtance of the Magnet is more porous, and leſſe
pact, which maketh that all the points and filaments of the
ſtone do not cloſe with that which it unites unto. In the next
place, that the ſubſtance of Iron (eſpecially the well refined, as
namely, the pureſt ſteel) is of parts much more denſe, ſubtil,
and pure than the matter of the Loadſtone, is ſeen, in that one
may bring its edge to an extraordinary ſharpneſſe, ſuch as is that
of the Raſor, which can never be in any great meaſure effected in
a piece of Magnet. Then, as for the impurity of the Magnet, and
its being mixed with other qualities of ſtone, it is firſt ſenſibly
diſcovered by the colour of ſome little ſpots, for the moſt part
white; and next by preſenting a needle to it, hanging in a
thread, which upon thoſe ſtonyneſſes cannot find repoſe, but
being attracted by the parts circumfuſed, ſeemeth to fly from
^{*} thoſe, and to leap upon the Magnet contiguous to them: and
as ſome of thoſe Heterogeneal parts are for their magnitude
ry viſible, ſo we may believe, that there are others, in great
bundance, which, for their ſmallneſſe, are imperceptible, that are
diſſeminated throughout the whole maſſe. That which I ſay,
(namely, that the multitude of contacts that are made between
Iron and Iron, is the cauſe of the ſo ſolid conjunction) is
firmed by an experiment, which is this, that if we preſent the
ſharpned point of a needle to the cap of a Magnet, it will ſtick
no faſter to it, than to the ſame ſtone unarmed: which can
proceed from no other cauſe, than from the equality of the
tacts that are both of one ſole point. But what then? Let a
^{*} Needle be taken and placed upon a Magnet, ſo that one of its
extremities hang ſomewhat over, and to that preſent a Nail; to
which the Needle will inſtantly cleave, inſomuch that
ing the Nail, the Needle will ſtand in ſuſpenſe, and with its two
ends touching the Magnet and the Iron; and withdrawing the
Nail yet a little further, the Needle will forſake the Magnet;
provided that the eye of the Needle be towards the Nail, and
the point towards the Magnet; but if the eye be towards the
Loadſtone, in withdrawing the Nail the Needle will cleave to
the Magnet; and this, in my judgment, for no other reaſon,
ſave onely that the Needle, by reaſon it is bigger towards the
eye, toucheth in much more points than its ſharp point doth.