300 HIXDOO ASTRONOMY. 



known, and the fractional part to be added will be the same 

 part of a day that the diflerence between the middle ampli- 

 tude and one of the extremes (that first observed) is to the 

 difference between the extremes. The amphtudes, or 

 rather their differences, are to be detennined by marking 

 the sun's position at rising on a horizontal circle of con- 

 siderable magnitude. This method is ingenious, and it 

 would be improved by observing the sun's position at rising 

 on several days before and after the year is completed. 

 Theoretically it is good, but probably it was never put in 

 practice ; and with any horizontal circle such as the Hin- 

 doos might be supposed to possess, was not likely to lead to 

 much certainty. 



The Surya Siddhanta being regarded as the most ancient 

 astronomical treatise among the Hindoos, it is important to 

 know the time at which it was composed. It is now gener- 

 ally admitted that the Hindoos are a very ancient people. 

 Bailly believed that their astronomy was founded on obser- 

 vations made more than 3000 years before the Christian 

 era ; and, in particular, that their tables of the sun and 

 moon were determined by actual observations made at the 

 beginning of their celebrated era the call yug, which was 

 3103 years before the Christian era. It might, however, 

 well be doubted whether they had any books of such extraor- 

 dinary antiquity. To dissipate these delusions J. Bentley, 

 Esq., has given to the world a memoir which has for its 

 object to determine the age of the Surya Suldhanfa,* and in 

 this he has clearly explained the manner in which their 

 tables were formed. We have seen that in the Hindoo sys- 

 tems certain parts of time were fixed on as epochs at which 

 the planets are assumed to have been in a line of mean 

 conjunction with the sun m the beginning of Aries. From 

 these the Hindoo astronomer carried on his calculations as 

 if they had been fixed by actual observation, and thence 

 determines such mean annual motion as will give the posi- 

 tions of the planets in his own times so as to correspond as 

 nearly as he can with the observations then made. 



In fixing on these epochs, the first Hindoo astronomers 

 took the precaution to throw them so far back into antiquity 

 that the difference between the assumed and real places, of 



* Asiatic Researches, vol. vi. p. 540. 



