EARLY ASTRONOMY. 147 



account of all the comets and remarkable stars observed be* 

 tween the years B.C. 613, and A.D. 1222. 



The tripartite didactic poem of Aratus,' to whom we are 

 indebted for the only remnant of the works of Hipparchus that 

 has come down to us, was composed about the period of Era- 

 tosthenes, Timocharis, and Aristyllus. The astronomical non- 

 meteorological portion of the poem is based on the uranograplry 

 of Eudoxus of Cnidos. The catalogue compiled by Hipparchus is 

 unfortunately not extant; but, according to Ideler, 10 it probably 

 constituted the principal part of his work, cited by Suidas, 

 " On the arrangement of the region of the fixed stars and the 

 celestial bodies," and contained 1080 determinations of posi- 

 tion for the year B.C. 128. In Hipparchus's other Commentary 

 on Aratus the positions of the stars, which are determined 

 more by equatorial armillae than by the astrolabe, are referred 

 to the equator by right ascension and declination; while in 

 Ptolemy's catalogue of stars, which is supposed to have been en- 

 tirely copied from that of Hipparchus, and which gives 1025 

 stars, together with five so-called nebulae, they are referred by 

 longitudes and latitudes to the ecliptic. 11 On comparing the 



* It is worthy of remark that Aratus was mentioned with 

 approbation almost simultaneously by Ovid (Amor., i. 15,) 

 and by the Apostle Paul, at Athens, in an earnest discourse 

 directed against the Epicureans and Stoics. Paul (Acts, ch. xvii. 

 v. 28), although he does not mention Aratus by name, un- 

 doubtedly refers to a verse composed by him (Phan., v. 5) on 

 the close communion of mortals with the Deity. 



10 Ideler, Untersuchungen uber den Ur sprung der Sternnamen, 

 s. xxx.-xxxv. Baily in the Mem. of the Astron. xSbc., vol. xiii. 

 1843, pp. 12 and 15, also treats of the years according to our 

 era, to which we must refer the observations of Aristyllus, as 

 well as the catalogues of the stars compiled by Hipparchus 

 (128, and not 140, B.C.) and by Ptolemy (138 A.D.). 



11 Compare Delambre, Hist, de I'Astr. anc., torn. i. p. 184 ; 

 torn. ii. p. 260. The assertion, that Hipparchus, in additiou 

 to the right ascenbion and declination of the stars, also iiidi- 



L2 



