Galilei, Galileo, Discourse concerning the natation of bodies, 1663

Table of figures

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              yond the poſſible Altitude of the Ramparts of water, it would dive
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              and ſink; but if whilſt it is going downwards, one ſhould make
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              certain Banks or Ramparts about it, that ſhould hinder the do fuſion
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              of the water upon the ſaid Plate, the which Banks ſhould riſe ſo
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              high, as that they might be able to contain as much water, as ſhould
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              weigh equally with the ſaid Plate, it would, without all Queſtion,
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              deſcend no lower, but would reſt, as being ſuſtained by vertue of
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              the Air contained within the aforeſaid Ramparts: and, in ſhort,
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              there would be a Veſſell by this means formed with the bottom of
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              Lead. </s>
              <s>But if the thinneſs of the Lead ſhall be ſuch, that a very
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              ſmall height of Rampart would ſuffice to contain ſo much Air, as might
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              keep it afloat, it ſhall alſo reſt without the Artificiall Banks or
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              parts, but yet not without the Air, becauſe the Air by it ſelf makes
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              Banks ſufficient for a ſmall height, to reſiſt the Superfuſion of the
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              water: ſo that that which in this caſe ſwimmes, is as it were a
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              Veſſell filled with Air, by vertue of which it continueth afloat.</s>
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              <s>I will, in the laſt place, with an other Experimeut, attempt to
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              remove all difficulties, if ſo be there ſhould yet be any doubt leſt in
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              any one, touching the opperation of this ^{*}Continuity of the Air, with </s>
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              the thin Plate which ſwims, and afterwards put an end to this part of
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              my diſcourſe.</s>
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              *Or rather
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              tiguity,</s>
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              <s>I ſuppoſe my ſelf to be queſtioning with ſome of my Oponents.</s>
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              <s>Whether Figure have any influence upon the encreaſe or
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              tion of the Reſiſtance in any Weight againſt its being raiſed in the
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              Air, and I ſuppoſe, that I am to maintain the Affirmative,
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              ing that a Maſs of Lead, reduced to the Figure of a Ball, ſhall be
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              raiſed with leſs force, then if the ſame had been made into a thinne
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              and broad Plate, becauſe that it in this ſpacious Figure, hath a great
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              quantity of Air to penetrate, and in that other, more compacted and
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              contracted very little: and to demonſtrate the truth of ſuch my
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              pinion, I will hang in a ſmall thred firſt the Ball or Bullet, and put
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              that into the water, tying the thred that upholds it to one end of
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              the Ballance that I hold in the Air, and to the other end I by degrees
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              adde ſo much Weight, till that at laſt it brings up the Ball of Lead
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              out of the water: to do which, ſuppoſe a Gravity of thirty Ounces
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              ſufficeth; I afcerwards reduce the ſaid Lead into a flat and thinne
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              Plate, the which I likewiſe put into the water, ſuſpended by three
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              threds, which hold it parallel to the Surface of the water, and
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              ting in the ſame manner, Weights to the other end, till ſuch time as
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              the Place comes to be raiſed and drawn out of the water: I finde
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              that thirty ſix ounces will not ſuffice to ſeperate it from the water,
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              and raiſe it thorow the Air: and arguing from this Experiment, I
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              firm, that I have fully demonſtrated the truth of my Propoſition.
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              </s>
              <s>He re my Oponents deſires me to look down, ſhewing me a thing </s>
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