Salusbury, Thomas, Mathematical collections and translations (Tome I), 1667
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              ed than thoſe of the Magnet, which are more groſſe, impure, and
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              rare. </s>
              <s>From whence it followeth, that the ſuperficies of two
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              rons that are to touch, by being exquiſitely plained, filed, and
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              burniſhed, do ſo exactly conjoyn, that all the infinite points of
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              the one meet with the infinite points of the other; ſo that the
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              filaments, if I may ſo ſay, that collegate the two Irons, are many
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              more than thoſe that collegate the Magnet to the Iron, by reaſon
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              that the ſubſtance of the Magnet is more porous, and leſſe
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              pact, which maketh that all the points and filaments of the
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              ſtone do not cloſe with that which it unites unto. </s>
              <s>In the next
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              place, that the ſubſtance of Iron (eſpecially the well refined, as
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              namely, the pureſt ſteel) is of parts much more denſe, ſubtil,
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              and pure than the matter of the Loadſtone, is ſeen, in that one
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              may bring its edge to an extraordinary ſharpneſſe, ſuch as is that
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              of the Raſor, which can never be in any great meaſure effected in
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              a piece of Magnet. </s>
              <s>Then, as for the impurity of the Magnet, and
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              its being mixed with other qualities of ſtone, it is firſt ſenſibly
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              diſcovered by the colour of ſome little ſpots, for the moſt part
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              white; and next by preſenting a needle to it, hanging in a
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              thread, which upon thoſe ſtonyneſſes cannot find repoſe, but
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              being attracted by the parts circumfuſed, ſeemeth to fly from
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              ^{*}
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              thoſe,
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              and to leap upon the Magnet contiguous to
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              them:
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              and
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              as ſome of thoſe Heterogeneal parts are for their magnitude
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              ry viſible, ſo we may believe, that there are others, in great
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              bundance, which, for their ſmallneſſe, are imperceptible, that are
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              diſſeminated throughout the whole maſſe. </s>
              <s>That which I ſay,
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              (namely, that the multitude of contacts that are made between
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              Iron and Iron, is the cauſe of the ſo ſolid conjunction) is
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              firmed by an experiment, which is this, that if we preſent the
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              ſharpned point of a needle to the cap of a Magnet, it will ſtick
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              no faſter to it, than to the ſame ſtone unarmed: which can
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              proceed from no other cauſe, than from the equality of the
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              tacts that are both of one ſole point. </s>
              <s>But what then? </s>
              <s>Let a
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              ^{*} Needle be taken and placed upon a Magnet, ſo that one of its
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              extremities hang ſomewhat over, and to that preſent a Nail; to
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              which the Needle will inſtantly cleave, inſomuch that
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              ing the Nail, the Needle will ſtand in ſuſpenſe, and with its two
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              ends touching the Magnet and the Iron; and withdrawing the
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              Nail yet a little further, the Needle will forſake the Magnet;
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              provided that the eye of the Needle be towards the Nail, and
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              the point towards the Magnet; but if the eye be towards the
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              Loadſtone, in withdrawing the Nail the Needle will cleave to
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              the Magnet; and this, in my judgment, for no other reaſon,
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              ſave onely that the Needle, by reaſon it is bigger towards the
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              eye, toucheth in much more points than its ſharp point doth.</s>
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