5g6 on the antiquity or 



first point of Aries to the same again ='— ^'' = 

 27"" 19" 18' 1" 17'" &c. andhersynodical revolution 

 or lunation = ^^^^ = <29''- Si'"' 50' 7" o2'" &c. or 

 according to the £z/ra/;<?^w expression 29^^- 12*^ 44' 

 2" 49'" &c. which does not differ the ninetieth part of 

 a second from the length of a lunation by De la 

 Lande's tables. The periodical revolutions of the 

 planets may be had exactly in the same manner, by 

 dividing the number of days in the cycle by the revo- 

 lutionsofeach. 



5 1 . The system being now compleated, the mean 

 longitudes of the Sun, Moon, and planets, are ob- 

 tained from the revolutions above given (§ 4-9) in the 

 manner already explained (^ 25) ; and their true lon- 

 gitudes, &c. are determined from thence by means 

 of equations. 



52. The equations of the orbits of the planets to 

 be met with in Hindu books, differ considerably 

 from those of Europeans, arising partly from the 

 manner in which they are computed, partly from the 

 inaccuracy of Hindu observation, and partly from 

 their antiquity. For most of the Hindu astronomers 

 for some ages back, appear to rest satisfied with 

 merely copying the equations given in the books of 

 those who preceded them. 1 he equations now .in 

 general use appear to have been given by Vara'ha 

 several centuries ago, and it is probable he copied 

 thehi from the works of some still earlier astronomer. 



53. Vara'ha has stated the obliquity of the eclip- 

 tic at twenty-four degrees, and the Hindu astronomers 

 siDce his time, appear to adopt ihat quantity. But 

 Vara'ha was not the first who gave the obliquity of 

 the ecliptic at twenty-four degrees; for, it would ap- 

 pear that Brohma Gupta, between five and six 

 centuries before hirny states it precisely the same. 

 We are not, however, to conclude from hence, that 



the 



