Salusbury, Thomas, Mathematical collections and translations (Tome I), 1667
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              <s>SIMP. </s>
              <s>The top will run reeling along the floor towards that
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              part whither its upper parts encline it.</s>
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              <s>SAGR. </s>
              <s>And why not whither the contrary parts tend, namely,
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              thoſe which touch the ground?</s>
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              <s>SIMP. </s>
              <s>Becauſe thoſe upon the ground happen to be impeded
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              by the roughneſs of the touch, that is, by the floors unevenneſs;
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              but the ſuperiour, which are in the tenuous and flexible air, are
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              hindred very little, if at all; and therefore the top will obey their
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              inclination.</s>
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              <s>SAGR. </s>
              <s>So that that taction, if I may ſo ſay, of the neither
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              parts on the floor, is the cauſe that they ſtay, and onely the upper
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              parts ſpring the top forward.</s>
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              <s>SALV. </s>
              <s>And therefore, if the top ſhould fall upon the ice, or
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              other very ſmooth ſuperficies, it would not ſo well run forward, but
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              might peradventure continue to revolve in it ſelf, (or ſleep)
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              out acquiring any progreſſive motion.</s>
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              <s>SAGR. </s>
              <s>It is an eaſie thing for it ſo to do; but yet
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              leſs, it would not ſo ſpeedily come to ſleep, as when it falleth on
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              a ſuperficies ſomewhat rugged. </s>
              <s>But tell me,
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              Simplicius,
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              when
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              the top turning round about it ſelf, in that manner, is let fall, why
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              doth it not move forwards in the air, as it doth afterwards when it
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              is upon the ground?</s>
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              <s>SIMP. </s>
              <s>Becauſe having air above it, and beneath, neither thoſe
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              parts, nor theſe have any where to touch, and not having more
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              caſion to go forward than backward, it falls perpendicularly.</s>
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              <s>SAGR. </s>
              <s>So then the onely reeling about its ſelf, without other
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              impetus,
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              can drive the top forward, being arrived at the ground,
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              very nimbly. </s>
              <s>Now proceed we to what remains. </s>
              <s>That laſh,
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              which the driver tyeth to his Top-ſtick, and with which, winding
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              it about the top, he ſets it (
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              i. </s>
              <s>e.
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              makes it go) what effect hath it on
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              the ſaid top?</s>
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              <s>SIMP. </s>
              <s>It conſtrains it to turn round upon its toe, that ſo it may
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              free it ſelf from the Top-laſh.</s>
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              <s>SAGR. </s>
              <s>So then, when the top arriveth at the ground, it cometh
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              all the way turning about its ſelf, by means of the laſh. </s>
              <s>Hath it
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              not reaſon then to move in it ſelf more ſwiftly upon the ground,
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              than it did whilſt it was in the air?</s>
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              <s>SIMP. </s>
              <s>Yes doubtleſs; for in the air it had no other impulſe
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              than that of the arm of the projicient; and if it had alſo the
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              ing, this (as hath been ſaid) in the air drives it not forward at all:
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              but arriving at the floor, to the motion of the arm is added the
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              progreſſion of the reeling, whereby the velocity is redoubled. </s>
              <s>And
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              I know already very well, that the top skipping from the ground,
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              its velocity will deminiſh, becauſe the help of its circulation is
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              wanting; and returning to the Earth will get it again, and by that </s>
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