102 PHILOSOPHICAL TRANSACTIONS. [aNNO 1727. 



the last and 54th page, tells iis, in his time followed the equinoctial colure the 

 20th part of an hour: and supposing the star that has disappeared, to have been 

 at that time precisely on the colure, it must differ but 45 minutes of right 

 ascension from it : but how he comes to make the difference of longitude 40 

 minutes, no way appears, and is gratis dictum. 



In page 49 of the said Florence edition, Hipparchus, treating of the rising 

 and setting of the constellations, tells us, that that of Aries began to rise with 

 18J- degree of Pisces in the ecliptic, and was wholly risen with the 24th degree 

 of Aries, while the zodiac passed the meridian from 23-i-° of Sagittary to 14° of 

 Capricorn : and again, page 52, he says, that the constellation of Aries began 

 to set with the 29th degree of Pisces, and was wholly set with the 26th degree 

 of Aries, while the zodiac passed the meridian from 29® of Gemini to 29° of 

 Cancer. He tell us also that it was the very same star that both rose and set 

 first in that constellation, calling it ^ttI tS £|U.7rfo?9i'K -rroSoi, page 49 : and again, 

 page 52, it is named it, tok i^ir^oi^ioi.!; TToa-iu, or that in the fore-feet of the 

 Ram. 



This certainly is the star P. Souciet would place on the equinoctial colure, 

 and makes it long since to have disappeared ; without inquiring whether the 

 aforesaid data were not abundantly sufficient to determine its place in the zodiac 

 at that time; and without regard to the odd uncouth posture he must suppose 

 the constellation of Aries to be in, when he makes one or both of the fore-feet 

 so near to, and above the horn or ear. 



Hipparchus expressly says, that it rose when 23-i-° of Sagittary was on the 

 meridian, and set when 29° of Gemini passed it; and taking the middle be- 

 tween those points, it is plain, that it culminated with about 26° of Pisces, and 

 that it had north declination ; the excess above 180° showing that the ascen- 

 sional difference was about 24-°. But to give the argument its full scope, the 

 right ascension of 23^- of Sagittary (allowing Hipparchus's obliquity 23° 5l' 

 20") "'ill be found 262° 54'. And that of 29° of Gemini will be 88° 54' : so 

 that this star was above the horizon (in the latitude of 36 degrees north, to 

 which Hipparchus has adapted his calculation) 12*^ 24'", or 180 degrees; whence 

 the right ascension of the star is justly concluded 355° 54', and its ascensional 

 difference precisely 3°; which in that latitude makes its declination 4° 7' north. 

 We have therefore gotten both the right ascension and declination of this sup- 

 posed first star of Aries. 



Let us now see what longitude and latitude results from the aforesaid right 

 ascension, with 4° 7' north declination, assuming the obliquity with Hipparchus, 

 to have been 23° 5l' 20" ; and we shall by a just computation, find the star at 

 that time to have been in 27° 53' of Pisces, 3° 24' north latitude, which there- 



