Indian Science and Technology in the Eighteenth Century: Some Contemporary European Accounts c9.48

c9.48

29. This, however, is not the only instance of the same kind that will occur, if, from examining the radical places and mean motions in the Indian astronomy, we proceed to consider some other of its elements, such as, the length of the year, the inequality of the sun’s motion, and the obliquity of the ecliptic, and compare them with the conclusions deduced, from the theory of gravity, by M. De La Grange. To that geometer, physical astronomy is indebted for one of the most beautiful of its discoveries, viz. that all the variations in our system are periodical; so that though every thing, almost without exception, be subject to change, it will, after a certain interval, return to the same state in which it is at present, and leave no room for the introduction of disorder, or of any irregularity that might constantly increase. Many of these periods, however, are of vast duration. A great number of ages, for instance, must elapse before the year be again exactly of the same length, or the sun’s equation of the same magnitude as at present.⁴⁶ An astronomy, therefore, which professes to be so ancient as the Indian, ought to differ considerably from ours in many of its elements. If indeed these differences are irregular, they are the effects of chance, and must be accounted errors; but if they observe the laws, which theory informs us that the variations in our system do actually observe, they must be held as the most undoubted marks of authenticity.