Salusbury, Thomas, Mathematical collections and translations (Tome I), 1667

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      <text>
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            <p type="main">
              <s>
                <pb xlink:href="040/01/360.jpg" pagenum="340"/>
              things; and that motion where it is common, is as if it never
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                <arrow.to.target n="marg641"/>
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              were; and as you change not habitude to the Terreſtrial Poles
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              (habitude I ſay, whether that they riſe, or deſcend) ſo neither
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              ſhall you change poſition to the Poles imagined in Heaven;
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              wayes provided that by Celeſtial Poles we underſtand (as hath
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              been already defined) thoſe two points that come to be marked
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              out by the prolongation of the Terreſtrial Axis unto that length.
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              </s>
              <s>Tis true thoſe points in Heaven do change, when the Earths
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              ſportment is made after ſuch a manner, that its Axis cometh to
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              paſſe by other and other points of the immoveable Celeſtial
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              Sphere, but our habitude thereunto changeth not, ſo as that the
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              ſecond ſhould be more elevated to us than the firſt. </s>
              <s>If any one
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              will have one of the points of the Firmament, which do anſwer
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              to the Poles of the Earth to aſcend, and the other to deſcend,
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              he muſt walk along the Earth towards the one, receding from the
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              other, for the tranſportment of the Earth, and with it us our
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              ſelves, (as I told you before) operates nothing at all.</s>
            </p>
            <p type="margin">
              <s>
                <margin.target id="marg641"/>
                <emph type="italics"/>
              Motion where
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              it is common, is as
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              if it never were.
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              </s>
            </p>
            <p type="main">
              <s>SAGR. </s>
              <s>Permit me, I beſeech you
                <emph type="italics"/>
              Salviatus,
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              to make this a
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              little more clear by an example, which although groſſe, is
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              commodated to this purpoſe. </s>
              <s>Suppoſe your ſelf,
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              Simplicius,
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              to
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                <arrow.to.target n="marg642"/>
                <lb/>
              be aboard a Ship, and that ſtanding in the Poope, or Hin-deck;
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              you have directed a Quadrant, or ſome other Aſtronomical
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              ſtrument, towards the top of the Top-gallant-Maſt, as if you
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              would take its height, which ſuppoſe it were
                <emph type="italics"/>
              v. </s>
              <s>gr.
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              40. degrees,
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                <arrow.to.target n="marg643"/>
                <lb/>
              there is no doubt, but that if you walk along the ^{*} Hatches
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              wards the Maſt 25. or 30. paces; and then again direct the ſaid
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              Inſtrument to the ſame Top-Gallant-Top. </s>
              <s>You ſhall find its
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              vation to be greater, and to be encreaſed
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              v. </s>
              <s>gr.
                <emph.end type="italics"/>
              10. degrees; but
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              if inſtead of walking thoſe 25. or 30. paces towards the Maſt,
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              you ſtand ſtill at the Sterne, and make the whole Ship to move
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              thitherwards, do you believe that by reaſon of the 25. or 30.
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              paces that it had paſt, the elevation of the Top-Gallant-Top
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              would ſhew 10. degrees encreaſed?</s>
            </p>
            <p type="margin">
              <s>
                <margin.target id="marg642"/>
                <emph type="italics"/>
              An example
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              ted to prove that
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              the altitude of the
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              Pole ought not to
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              vary by means of
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              the Earths annual
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              motion.
                <emph.end type="italics"/>
              </s>
            </p>
            <p type="margin">
              <s>
                <margin.target id="marg643"/>
              *
                <emph type="italics"/>
              Corſia,
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              the bank
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              or bench on which
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              ſlaves ſit in a
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              ly.</s>
            </p>
            <p type="main">
              <s>SIMP. </s>
              <s>I believe and know that it would not gain an hairs
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              breadth in the paſſing of 30. paces, nor of a thouſand, no nor of
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              an hundred thouſand miles; but yet I believe withal that
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              ing through the ſights at the Top and Top-Gallant, if I ſhould
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              find a fixed Star that was in the ſame elevation, I believe I ſay,
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              that, holding ſtill the Quadrant, after I had ſailed towards the
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              ſtar 60. miles, the eye would meet with the top of the ſaid
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              Maſt, as before, but not with the ſtar, which would be
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              ted to me one degree.</s>
            </p>
            <p type="main">
              <s>SAGR. </s>
              <s>Then you do not think that the ſight would fall upon
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              that point of the Starry Sphere, that anſwereth to the direction
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              of the Top-Gallant Top?</s>
            </p>
          </chap>
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