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

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            <pb xlink:href="040/01/279.jpg" pagenum="259"/>
            <p type="main">
              <s>SALV. </s>
              <s>I ſee that you underſtand the buſineſſe very well. </s>
              <s>I
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              lieve that you do likewiſe comprehend, that, in regard the ſtar B
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              is lower than C, the angle which is made by the rayes of the
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              ſight, which departing from the two places A and E, meet in C,
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              to wit, this angle A C E, is more narrow, or if we will ſay more
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              acute than the angle conſtituted in B, by the rayes A B and
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              E
                <emph type="italics"/>
              B.
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              </s>
            </p>
            <p type="main">
              <s>SIMP. </s>
              <s>This I likewiſe underſtand very well.</s>
            </p>
            <p type="main">
              <s>SALV. </s>
              <s>And alſo, the Earth beine very little and almoſt
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              ſible, in reſpect of the Firmament
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              (or Starry Sphere
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              ;) and
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              ſequently the ſpace A E, paced on the Earth, being very ſmall in
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              compariſon of the immenſe length of the lines E G and E F,
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              ſing from the Earth unto the Firmament, you thereby collect that
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              the ſtar C might riſe and aſcend ſo much and ſo much above the
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              Earth, that the angle therein made by the rayes which depart
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              from the ſaid ſtationary points A and E, might become moſt
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              cute, and as it were abſolutely null and inſenſible.</s>
            </p>
            <p type="main">
              <s>SIMP. </s>
              <s>And this alſo is moſt manifeſt to ſenſe.</s>
            </p>
            <p type="main">
              <s>SALV. </s>
              <s>Now you know
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              Simplicius
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              that Aſtronomers and
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              thematicians have found infallible rules by way of Geometry and
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              Arithmetick, to be able by help of the quantity of theſe angles
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                <emph type="italics"/>
              B
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              and C, and of their differences, with the additional knowledg
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              of the diſtance of the two places A and E, to find to a foot the
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              remoteneſſe of ſublime bodies; provided alwayes that the
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              ſaid diſtance, and angles be exactly taken.</s>
            </p>
            <p type="main">
              <s>SIMP. </s>
              <s>So that if the Rules dependent on
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              Geometry
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              and
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              nomy
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              be true, all the fallacies and errours that might be met with
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              in attempting to inveſtigate thoſe altitudes of new Stars or
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              mets, or other things muſt of neceſſity depend on the diſtance A E,
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              and on the angles B and C, not well meaſured. </s>
              <s>And thus all thoſe
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              differences which are found in theſe twelve workings depend, not
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              on the deſects of the rules of the Calculations, but on the errours
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              committed in finding out thoſe angles, and thoſe diſtances, by means
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              of the Inſtrumental Obſervations.</s>
            </p>
            <p type="main">
              <s>SALV. True; and of this there is no doubt to be made. </s>
              <s>Now
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              it is neceſſary that you obſerve intenſely, how in removing the Star
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              from B to C, whereupon the angle alwayes grows more acute, the
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              ray E B G goeth farther and farther off from the ray A B D in
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              the part beneath the angle, as you may ſee in the line E C F,
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              whoſe inferiour part E C is more remote from the part A C, than
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              is the part E B, but it can never happen, that by any whatſoever
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              immenſe receſſion, the lines A D and E F ſhould totally ſever from
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              each other, they being finally to go and conjoyn in the Star: and
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              onely this may be ſaid, that they would ſeparate, and reduce
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              ſelves to parallels, if ſo be the receſſion ſhould be infinite, which </s>
            </p>
          </chap>
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