Mifcellanea Curiofa. 205 



Diftance of thofe Points from the Axis. Of 

 this there are two Cafes, the one when the 

 Time of the fecond Obfervation B is pre- 

 cifely in the middle Time between A and C: 

 In this Cafe putting t for the whole Time 

 between A and C, we fhall have A c the In- 

 terval of the remoteft Obfervation A from 

 the Tropick by the following Analogy. 



As 2 a 0— b c to 2 a o— i be:: So is \ t 

 or A E : to A c the Time of the remotefl 

 Obfervation A from the Tropick. 



But the other Cafe when the middle Ob- 

 fervation is not exactly in the middle be- 

 tween the other two Times, as at F r is fome- 

 thing more operofe, and the whole Time 

 from A to C being put — t, and from A to 

 F = s, ce = c, and b c = b, the Theorem 

 1 1 c — b s s 



will ftand thus < — = A c at the Time 



2 1 0 — 2 b s 



fought. 



To illuftrate this Method of Calculation it 

 may perhaps .be requiilte to give an Exam- 

 ple or two for the fake of thofe Aftrono- 

 mers that are lefs inftru&ed in the Geome- 

 trical part of their Art. 



Anno 1500. Bernard Walther,ii\ the Month 

 of June, d£ Nuremburg r obferv'd the Chord 

 of the diftance of the Sun from the Zenith 

 by a large Paralla&ick Inftrument of Ptolemy^ 

 as follows : 



June 2. 454^7. Jme 8. 44975* 



June 9. 44934* and 12. 44883. 



June id. 44990. June 16. 4499a. 



In 



