Salusbury, Thomas, Mathematical collections and translations (Tome I), 1667
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              ſtanding of which, I ought firſt to advertiſe you, that when ever
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              the new Star, or other Phænomenon is near to the earth, turning
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              with a Diurnal motion about the Pole, it will ſeem to be farther
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              off from the ſaid Pole, whilſt it is in the lower part of the
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              an, then whilſt it is above, as in this Figure [
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              being fig. </s>
              <s>third of
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              this Dial.
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              ] may be ſeen. </s>
              <s>In which the point T. denotes the
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              tre of the Earth; O the place of the Obſervator; the Arch VPC
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              the Firmament; P. the Pole. </s>
              <s>The
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              Phænomenon,
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              [
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              or appearance
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              ]
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              moving along the Circle F S. is ſeen one while under the Pole by
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              the Ray O F C. and another while above, according to the Ray
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              O S D. ſo that the places ſeen in the Firmament are D. and C. but
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              the true places in reſpect of the Centre T, are B, and A,
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              ſtant from the Pole. </s>
              <s>Where it is manifeſt that the apparent place
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              of the
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              Phænomenon
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              S, that is the point D, is nearer to the Pole than
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              the other apparent place C, ſeen along the Line or Ray O F C,
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              which is the firſt thing to be noted. </s>
              <s>In the ſecond place you muſt
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              note that the exces of the apparent inferiour diſtance from the Pole,
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              over and above the apparent ſuperiour diſtance from the ſaid Pole,
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              is greater than the Inferiour Parallax of the
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              Phænomenon,
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              that is, I
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              ſay, that the exceſſe of the Arch C P, (the apparent inferior
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              ſtance) over and above the Arch P D, (the apparent ſuperior
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              ſtance) is greater then the Arch C A, (that is the inferiour
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              lax.) Which is eaſily proved; for the Arch C P. more exceedeth
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              P D, then P B; P B, being bigger than P D, but P B. is equal to
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              P A, and the exceſſe of C P, above P A, is the arch, C A,
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              fore the exceſſe of the arch C P above the arch P D, is
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              er than the arch C A, which is the parallax of the Phænomenon
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              placed in F, which was to be demonſtrated. </s>
              <s>And to give all
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              vantages to the Author, let us ſuppoſe that the parallax of the ſtar
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              in F, is the whole exceſſe of the arch C P (that is of the inferiour
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              diſtance from the pole) above the arch P D (the inferiour
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              ſtance.) I proceed in the next place to examine that which the
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              obſervations of all Aſtronomers cited by the Authour giveth us,
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              amongſt which, there is not one that maketh not againſt himſelf
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              and his purpoſe. </s>
              <s>And let us begin with theſe of
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              Buſchius,
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              who
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              findeth the ſtars diſtance from the pole, when it was ſuperiour, to be
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              28
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              gr. </s>
              <s>10 m.
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              and the inferiour to be 28
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              gr. </s>
              <s>30 m.
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              ſo that the
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              ceſſe is 0
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              gr. </s>
              <s>20 m.
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              which let us take (in favour of the Author) as
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              if it all were the parallax of the ſtar in F, that is the angle T F O.
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              </s>
              <s>Then the diſtance from the
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              Vertex
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              [or Zenith] that is the arch
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              C V, is 67
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              gr. </s>
              <s>20 m.
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              Theſe two things being found, prolong the
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              line C O, and from it let fall the perpendicular T I, and let us
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              conſider the triangle T O I, of which the angle I is right angle,
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              and the angle I O T known, as being vertical to the angle V O C,
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              the diſtance of the ſtar from the
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              Vertex,
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              Moreover in the triangle </s>
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