"TRlGONOMETRr of the BRAHMIlStS. loi 



had no knowledge of the antiquity of the Surya Siddhanta, 

 that the trigonometry contained in it is not borrowed from 

 Greece or Arabia, as its fundamental rule was unknown to the 

 geometers of both thofe countries, and is greatly preferable to 

 that which they employed. 



lo. Considerable light may perhaps hereafter be thrown 

 • on this argument, if it be found that the Surya Siddhanta con- 

 tains a demonftration of this rule. It does not appear, however,, 

 from the fragment we are in polTelTion of, that any explanation 

 of the rule is given, either in that work, or in the commentary.. 

 Indeed I am not certain that the Surya Siddhanta contains any 

 thing but rules and maxims, or that the author of it condefcends 

 to give any demonflrations of the propofitions which he enun- 

 ciates. He may have felt himfelf relieved from the neceffityof 

 doing fo, by his claim to infpiration ; and as he probably valued 

 himfelf more on the chara(5ler of a prophet, than of a geometer, 

 he may rather have inclined to exercife the faith, than the rea- 

 fon, of his difciples. 



However that be, by the rule above explained, the Brah- 

 mins have computed a fet of tables, limited indeed in their accu- 

 racy, but extremely fimple and compendious. The rule is eafily 

 remembered by one who has been accuftomed to numeri- 

 cal calculation, and is fuch, that, by help of it, he may at 

 any time compofe for himfelf a complete fet of trigonometrical 

 tables, in a few hours, without the affiftance of any book what- 

 ever. For the purpofe of rendering it thus fimple, the con- 

 trivance of meafuring the radius, and all the fines, in parts of 

 the circumference, feems to have been adopted: if we follow any 

 other method,, the rule, though it remain the fame in reality, 

 will alTume a form much lefs eafy to be retained in the me- ■ 

 mory *. It has the appearance, like many other things in the 



fcience 



* This feems to me the mod probable reafon that can be affigned for tlie mea- 

 furing of the radius, and the other ftraight lines in the circle, in parts of the circum- 



