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

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              <s>
                <pb pagenum="437"/>
              with water, as ſoon as its ſuperiour Superficies, before vailed with
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              water, doth arrive to the Levell of the univerſall Surface of the ſaid
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              water. </s>
              <s>To ſay, in the next place, that water can encreaſe the weight
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                <arrow.to.target n="marg1475"/>
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              of things that are demitted into it, is moſt falſe, for water hath no
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              Gravity in water, ſince it deſcends not: yea, if we would well
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              der what any immenſe Maſs of water doth put upon a grave Body;
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                <arrow.to.target n="marg1476"/>
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              that is placed in it, we ſhall find experimentally, that it, on the
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              trary, will rather in a great part deminiſh the weight of it, and that
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              we may be able to lift an huge Stone from the Bottom of the water,
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              which the water being removed, we are not able to ſtir. </s>
              <s>Nor let
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              them tell me by way of reply, that although the ſuperpoſed water
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              augment not the Gravity of things that are in it, yet it increaſeth the
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              ponderoſity of thoſe that ſwim, and are part in the water and part
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                <arrow.to.target n="marg1477"/>
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              in the Air, as is ſeen, for Example, in a Braſs Ketle, which whilſt it
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              is empty of water, and repleniſhed only with Air ſhall ſwim, but
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              pouring of Water therein, it ſhall become ſo grave, that it ſhall ſink
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              to the Bottom, and that by reaſon of the new weight added thereto.
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              </s>
              <s>To this I will return anſwer, as above, that the Gravity of the
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              Water, contained in the Veſſel is not that which ſinks it to the
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              tom, but the proper Gravity of the Braſs, ſuperiour to the Specificall
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                <arrow.to.target n="marg1478"/>
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              Gravity of the Water: for if the Veſſel were leſs grave than
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              water, the Ocean would not ſuffice to ſubmerge it. </s>
              <s>And, give me
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              leave to repeat it again, as the fundamentall and principall point in
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              this Caſe, that the Air contained in this Veſſel before the infuſion of
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              the Water, was that which kept it a-float, ſince that there was made
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                <arrow.to.target n="marg1479"/>
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              of it, and of the Braſs, a Compoſition leſs grave than an equall
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              ty of Water: and the place that the Veſſel occupyeth in the
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              Water whilſt it floats, is not equall to the Braſs alone, but to the
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              Braſs and to the Air together, which filleth that part of the Veſſel
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              that is below the Levell of the water: Moreover, when the Water
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              is infuſed, the Air is removed, and there is a compoſition made of
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              Braſs and of water, more grave
                <emph type="italics"/>
              in ſpecie
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              than the ſimple water, but
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              not by vertue of the water infuſed, as having greater Specifick
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              Gravity than the other water, but through the proper Gravity of
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              the Braſs, and through the alienation of the Air. </s>
              <s>Now, as he that
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              ſhould ſay that Braſs, that by its nature goes to the Bottom, being
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                <arrow.to.target n="marg1480"/>
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              formed into the Figure of a Ketle, acquireth from that Figure a
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              vertue of lying in the Water without ſinking, would ſay that which
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              is falſe; becauſe that Braſs faſhioned into any whatever Figure,
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              goeth always to the Bottom, provided, that that which is put into the
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              water be ſimple Braſs; and it is not the Figure of the Veſſel that
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              makes the Braſs to float, but it is becauſe that that is not purely
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              Braſs which is put into the water, but an aggregate of Braſs and of
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              Air: ſo is it neither more nor leſs falſe, that a thin Plate of Braſs </s>
            </p>
          </chap>
        </body>
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    </archimedes>
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