220 ! HINDU" ASTRONOMERS'. 



I Kr-AVE dwelt the longer upon the hiftory- of this opinion, becaufe- tfe. 

 appears to me deferving- of attention on more than one account Alba- 

 tani is the earlielt of. the Arabian- altronomers- who improved upon. 

 Ptolemy. (For Alfargani, who.was-a century earlier, is not cited 

 as correcting the Greek aftronomer oa this point;) It was he then, 

 who firft, among the aftronomers of the Weft of Ada, computed the 

 motion of the ftars at a degree in 66 years ; which is almoit the fame 

 with the rate- of the motion of trepidation according - to the Sarya- 

 fidd'lidnta, and the herd of Hindu aftronomers, who reckon a degree 

 and a half in a century,. * He is the firft alfo, as- far as can be dis- 

 covered* in whofe works mention is made of- a motion of trepidation, 

 and we may be permitted to conjecture,, that the earlier aftronomers 

 alluded to by him were Indian; lince we find A'ryabhatVa, an 

 author feemingly of an earlier age, quoted for a libration of the equi- 

 noctial points within the limits of twenty four degrees, at the rate of 

 one in 78 years; and fmce we know that an Arabian aftronomer, an- 

 terior by nearly a century to Albatani, had compiled tables.- in. 

 conformity to rules of aftionomy apparently ■ Indian t '\- 



We may. then fafely conclude, .that, on the-.Tubject -of the preceffion 

 of the equinoxes, the Hindus had, a theory, which, though erroneous,, 



was their own: and, which, at a fubfequent time, found advocates 

 among the -aftronomers of the weft, That they had a knowledge of 



* This it the rate refultssg ff om the quantity of the motion in trep'dadon fTated in the Sufya fild'hanta : 

 and the fame refu!ts from the rules of calculation given in the BhasivatS-carana of Satakanda and in 

 the JStacdrnava improperly afcribed to Vakaha-mihi2A. They both direct the number 4:1 to be 

 deducted from (the expired y*ars of S'aca ; and the- -one dedufls a tenth and reduces the remainder into 

 degrees; the other adds half and divides by a hundred. Another rule, producing the f me refu?r, ii 

 mentioned, in Bailly's A3. Ind. p. 76. 



+ » Ad Regulos Send Hcnd." (SiJd'bdnt> J Abalfarag. Hill, Dynaft. p, 114, and i&l, Costar-jjV 

 Agronomy 9 . p, 557.. aatJ Montucla Hift» dssmatiVp. 34i« 



