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

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              <s>
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              downwards, and alſo forwards or backwards ten or fifteen fathom,
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              keeping it all the while parallel to its ſelf, the viſive ray cannot
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              ſtray from the point obſerved in the object, more than thoſe
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              teen fathom; and becauſe in a diſtance of eight or ten miles, the
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              Inſtrument takes in a much greater ſpace than the Gally or other
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              Veſſel kenn'd; therefore that ſmall mutation ſhall not make me
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              loſe ſight of her. </s>
              <s>The impediment therefore, and the cauſe of
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              loſing the object cannot befall us, unleſſe upon the mutation made
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              angularly; ſince that
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              Teleſcopes
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              tranſportation higher or lower, to
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              the right, or to the left, by the agitation of the ſhip, cannot import
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              any great number of fathomes. </s>
              <s>Now ſuppoſe that you had two
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                <emph type="italics"/>
              Teleſcopes
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              fixed, one at the Partners cloſe by the Deck, and the
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              ther at the round top, nay at the main top, or main top-gallant
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              top, where you hang forth the
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              Pennon
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              or ſtreamer, and that they
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              be both directed to the Veſſel that is ten miles off, tell me,
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              ther you believe that any agitation of the ſhip, & inclination of the
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              Maſt, can make greater changes, as to the angle, in the higher tube,
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              than in the lower? </s>
              <s>One wave ariſing, the prow will make the main
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              top give back fifteen or twenty fathom more than the foot of the
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              Maſt, and it ſhall carry the upper tube along with it ſo greata ſpace,
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              & the lower it may be not a palm; but the angle ſhall change in one
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              Inſtrument aſwell as in the other; and likewiſe a ſide-billow ſhall
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              bear the higher tube an hundred times as far to the Larboard or
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              Starboard, as it will the other below; but the angles change not at
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              all, or elſe alter both alike. </s>
              <s>But the mutation to the right hand or
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              left, forwards or backwards, upwards or downwards, bringeth no
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              ſenſible impediment in the kenning of objects remote, though the
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              alteration of the angle maketh great change therein; Therefore it
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              muſt of neceſſity be confeſſed, that the uſe of the
                <emph type="italics"/>
              Teleſcope
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              on the
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              round top is no more difficult than upon the Deck at the Partners;
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              ſeeing that the angular mutations are alike in both places.</s>
            </p>
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              <s>SALV. </s>
              <s>How much circumſpection is there to be uſed in affirming
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              or denying a propoſition? </s>
              <s>I ſay again, thar hearing it reſolutely
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              med, that there is a greater motion made on the Maſts top, than at
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              its partners, every one will perſwade himſelf, that the uſe of the
                <emph type="italics"/>
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              leſcope
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              is much more difficult above than below. </s>
              <s>And thus alſo I w
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              ill excuſe thoſe Philoſophers, who grow impatient and fly out into
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              paſſion againſt ſuch as will not grant them, that that Cannon bullet
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              which they cleerly ſee to fall in a right line perpendicularly, doth
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              abſolutely move in that manner; but will have its motion to be by
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              an arch, and alſo very much inclined and tranſverſal: but let us
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              leave them in theſe labyrinths, and let us hear the other objections,
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              that our Author in hand brings againſt
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              Copernicus.
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              </s>
            </p>
            <p type="main">
              <s>SIMP. </s>
              <s>The Author goeth on to demonſtrate that in the
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              ctrine of
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              Copernicus,
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              it is requiſite to deny the Senſes, and the </s>
            </p>
          </chap>
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