Indian Science and Technology in the Eighteenth Century: Some Contemporary European Accounts c9.53

c9.53

32. In this reasoning, however, it seems impossible to acquiesce; and. M. Bailly himself does not appear to have relied on it with much confidence.52 We are not at liberty to suppose, that the precession of the equinoxes increases in the ratio above mentioned, or, which is the same, that the equinoctial points go back with a motion equably retarded. If, by M. De La Grange’s formula, we trace back, step by step, the variation of the solar year, we shall find, that about the beginning of the Calyougham, it had nearly attained the extreme point of one of those vibrations, which many centuries are required to complete; and that the year was then longer than it has ever been since, or than it had been for many ages before. It was 40½″ longer than it is at present; but, at the year 5500 before Christ, it was only 29″ longer than at present, instead of 2′, 50″, which is the result of M. Bailly’s supposition. During all the intervening period of 2400 years, the variation of the year was between these two quantities; and we cannot therefore, by any admissible supposition, reduce the error of the tables to less than 1′, 5″. The smallness of this error, though extremely favourable to the antiquity, as well as the accuracy of the Indian astronomy, is a circumstance from which a more precise conclusion can hardly be deduced.