"290 HINDOO ASTRONOSIY. 



the Hindoo sphere. It was Mr. Davis's opinion that the 

 Hindoo science of astronomy is as well understood at this 

 time as ever it was among them ; but that it is less general 

 because of the want of that encouragement which was for- 

 merly given to men of science by the native princes. 



In constructing tables of the celestial motions, astrono- 

 mers fix on some epoch from which, as a beginning, they 

 reckon the motions of the planets. The ancient Hindoos 

 chose for their epoch that point of time counted back into 

 past ages, when, according to their motions, as they had 

 detemiTned them, they must have been in conjunction in 

 the beginning of Mesha, which corresponded to our Aries, 

 and they suppose that the v.orld was then created. This, 

 in rcfrard to the planets only, would have produced a mode- 

 rate term of years ; but having discovered a slow motion 

 of the nodes and apsides, they found that it would require 

 a length of time con-esponding with 1,955,884,890 years, 

 now expired, when they were so situated, and 2,364,115,110 

 years more before they would return to the same situ- 

 ation, fonning together the grand anomalistic period called 

 a calpa, and fancifully assigned as a day of Brama. They 

 divided the calpa into manwantarvas, and greater and less 

 tingas. The use of the mamvaniara is not stated in the 

 'Sur)/a Siddha7ita, but that of the viaha or greater yug is 

 sufficiently evident. It is an anomalistic period of the sun 

 and moon, at the end of which the latter, with her apogee 

 and ascending node, is found with the sun in the first point 

 of Aries ; the planets also deviating from that point only 

 by the diflerence between their mean and true anomaly. 

 These cycles being so constructed as to contain a certain 

 •number of mean solar days, and the Hindoo system assum- 

 ing that at the creation, when the planets began their mo- 

 tions, a straight line drawn from the equinoctial point 

 Lanca, through the centre of the earth, would, if continued, 

 have passed through the centre of the sun and planets to 

 the first star in Aries, it was easy to compute their mean 

 longitude for any time afterward by proportion, thus : — 

 As the number of days in any cycle to the revolutions a 

 planet makes in that cycle, so are the days given to its mo- 

 •cion in that time ; and the even revolutions being rejected, 

 the fraction, if any, shows its mean longitude at midnight 

 under their first meridian of Lanca. For places east or 



