444 Astronomical and Nautical Collections, 



Sum. 



.128 

 .162 

 .186 

 .201 

 .217 

 .233 

 .333 

 .398 



The principal observations of the vernal equinox, made by 

 Hipparchus, were in the years 



602, Mechir 27, 2h. before N. ; 60ly 175.917^- 145. 512^, 

 613, Mechir29, 12h. ; 612^ 178. 5^ -148. 176^. 



620, Phamenoth 1, 6h. ; 619^ 180.25* -149.870d. 



the first gives 30.405, the second 30.324, and the third 

 30.389 for the time of the vernal equinox in the first year of 

 Nabonassar: the mean being 30.366. But the two latter 

 observations being confirmed by their coincidence with those 

 of the intervening equinoxes, thev. must be allowed to prepon- 

 derate in some small degree, ana ve must call the most 

 probable mean about 30.360, and the epoch 



^ -746y-30.36d. 



It can hardly be supposed, however, that this number is 



much more decidedly accurate than 30 . 40 ; but some further 



corrections might possibly be obtained from the early eclipses, 



if greater precision were of any importance. 



1, Paophi (II.) 1, at 9jh., was consequently the eq. ® — 746^. 



27, Thoth (I.) 29, 2J hours before midnight at Babylon was the 

 middle of a total lunar eclipse, which lasted in the whole four 

 hours. (Ptolemy, p. 95, Ed. B. p. 244, H.) The interval is 



26 E. y. 28|^ days, allowing for the difference of longitude ; 

 the days wanting 6.29; and the whole time elapsed 26^ 

 22. 15d, making ^ -720^—8. 2 1^. 



Ideler has computed the time of this eclipse from Mayer s 

 tables, and finds the beginning a minute later, the end six 

 minutes earher than the observation recorded by Ptolemy. 

 Burg's tables agree much less accurately : but still later astro- 

 nomers have corrected the node nearly in the manner that 

 Ideler has suggested. The sun's true longitude is made by 

 Ptolemy 354° 30'. 



" This was the 1st year of Mardoc Empadus." 



28, Thoth (I.) 18, at the midnight of Babylon, was the middle of 

 a lunar eclipse of three digits. (P. 95, B. p. 245 H.) Now 



27 E. y. 17.46<i are 27 eq. y. 10.93<^; whence we have 



© .-.7i9y_i9.43d. 



