92 SPECIAL RESULTS IN THE URANOLOGICAL PORTION 



part of the poem is founded on the description of the heavens 

 given by Eudoxus of Cnidos. The star- table of Hipparclms 

 has unhappily not been preserved to us : according to 

 Ideler( 176 ) it probably formed the principal part of the 

 treatise, cited by Suidas, on the arrangement of the heaven 

 of the fixed stars and the other heavenly bodies, and con- 

 tained 1080 positions for the year 128 before our Era. In 

 Hipparchus's Commentary, all the positions, determined 

 probably by equatorial armillae rather than by the astrolabe, 

 are referred to the equator by right ascension and declina- 

 tion ; in the star-table of Ptolemy, which is supposed to be 

 altogether imitated from Hipparchus, and which, including 

 five so-called nebulse, contains 1025 stars, they are referred 

 to the Ecliptic ( 177 ) by assigned longitudes and latitudes. 

 If we compare the number of fixed stars in the Almagest, 

 (ed. Halma, T. ii. p. 83), 



1st mag. 2nd mag 1 . 3rd mag. 4th mag. 5th mag. 6th mag. 



15 45 208 474 217 49 



with the numbers of Argelander in a previous page, we see 

 (with a neglect of stars of the 5th and 6th magnitudes which 

 was to be expected,) a remarkable fulness in the 3rd and 

 4th magnitudes. The indeterminateness of estimations of 

 the degree of light in ancient and modern times does, indeed, 

 throw great uncertainty on every direct comparison. 



If the catalogue of the fixed stars, which bears the name 

 of Ptolemy, only comprises a fourth part of the stars visible 

 to the naked eye at Rhodes and Alexandria, and if, from 

 the erroneous reduction for precession, it gives positions as 

 if they had been determined in the year 63 of our Era, we 

 have in the next sixteen centuries only three original, and 



