108 COSMOS. 



% 



and who comments on his boldness in attempting, as it were, 

 " to leave heaven as a heritage to posterity," should have 

 enumerated only 1600 stars visible in the fine sky of Italy !* 

 In this enumeration he had, however, descended to stars of 

 the fifth, while half a century later Ptolemy indicated only 

 1025 stars down to the sixth magnitude. 



Since it has ceased to be the custom to class the fixed stars 

 merely according to the constellations to which they belong, 

 and they have been catalogued according to determinations 

 of place, that is, in their relations to the great circles of the 

 equator or the ecliptic, the extension as well as the accuracy 

 of star catalogues has advanced with the progress of science 

 and the improved construction of instruments. No catalogues 

 of the stars compiled by Timocharis and Aristyllus (283 B.C.) 

 have reached us ; but although, as Hipparchus remarks in 

 the fragment " on the length of the year," cited in the sev- 

 enth book of the Almagest (cap. 3, p. xv., Halma), their ob- 

 servations were conducted in a very rough manner {jrdvv 

 bXooxepu<;), there can be no doubt that they both determ- 

 ined the declination of many stars, and that these determin- 

 ations preceded by nearly a century and a half the table of 

 fixed stars compiled by Hipparchus. This astronomer is said 

 to have been incited by the phenomenon of a new star to 

 attempt a survey of the whole firmament, and endeavor to 

 determine the position of the stars ; but the truth of this 

 statement rests solely on Pliny's testimony, and has often 

 been regarded as the mere echo of a subsequently invented 

 tradition.! It does indeed seem remarkable that Ptolemy 

 should not refer to the circumstance, but yet it must be ad- 

 mitted that the sudden appearance of a brightly luminous 



* " Patrociiiatur vastitas cceli, immensa discreta altitudine, in duo at- 



3ue septuaginta signa. Haec sunt rerum et animantium effigies, in quas 

 igessere coelum periti. In his quidem mille sexcentas adnotavere Stel- 

 las, insignes videlicet effectu visuve" .... Plin., ii., 41. "Hipparchus 

 nunquam satis laudatus, ut quo nemo magis approbaverit cognationem 

 cum homine siderum animasque nostras partem esse cceli, novam slel 

 lam et aliam in a;vo suo genitam deprehendit, ejusque motu, qua die 

 fulsit, ad dubitationem est ad ductus, aune hoc saepius fieret moveren- 

 turque et ese quas putamus affixas ; itemque ansus rem etiam Deo im- 

 probam, adnumerare posteris Stellas ac sidera ad nomen expungere, or- 

 ganis excogitatis, per quae singularum loca atque magnitudines signaret, 

 ut facile discerni posset ex eo, non modo an obirent nascerenturve, sed 

 an omnino aliqua transirent moverenturve, item an crescei'ent minue- 

 renturque, ccelo in hereditate cuuctis relicto, si quisquam qi> ; cretionem 

 earn caperet inventus esset." Plin., ii., 26. 



t Delambre, Hist, de V Astr. Anc, torn, i., p. 290, and Hist, de VAslr. 

 Mod., torn, ii., p. 186. 



