Page:Popular Science Monthly Volume 55.djvu/414

398 among the Greeks from Thales to Aristotle, and also acquainted with all the progress in the physical and mathematical sciences that had been achieved by the Alexandrian astronomers in the last centuries before Christ. To comprehend the extent of the influence of Hellenic science, we have only to inquire what Hindu astronomy had bcomebecome [sic] again at the time of the restoration of the Brahmans in the sixth century A.D. Aryabhatta teaches the rotation of the earth around its axis; maintains that the moon, naturally dark, owes its light to the rays of the sun; formulates the true theory of eclipses; assigns an elliptical form to the planetary epicycles; and demonstrates the displacement of the equinoctial and solstitial points. Varaha-Mihira devotes himself especially to astrological labors, but also has the merit of having condensed into a vast encyclopædia the Pantcha Siddhântikâ, the principal astronomical treatises that were current in India. And Brahmazoupta is especially famous for his revision of an older treatise, the Brahma Siddhânta.

In the opinion of the most competent critics, these works, which are chiefly empirical methods of determining the positions of the stars, are inferior to those which the Alexandrians have left us. Yet, in matters relating to the measurement of arcs and to spherical trigonometry, they reveal a more advanced state of the science. It is impossible to determine at what period this new astronomical science was constituted in India. Some of its theories squarely betray their indebtedness to Greek science, as, for instance, that of the displacement of the equinoctial and solstitial points by a periodical vibration or tremor. We can also say as much of the solar zodiac, the names of the constellations of which strikingly resemble the Greek names in form as well as in significance, and the same of the names of the chief planets. Other expressions are found, notably in the works of Vahâra-Mihira, which indicate, if not a borrowing, a contact, at least, with the works of the Greek astronomy, of which Mr. Burgess gives a fairly complete list in his Notes on Hindu Astronomy and the History of our Knowledge of it, in the Journal of the Royal Asiatic Society. Among these terms, some are Greek words which have been utilized in naming constellations or astronomical measures; others have retained the special significations which they had in the works of the Alexandrian astronomers. It would certainly be an exaggeration to insist that the adoption of a foreign term of necessity implies the borrowing of the idea which it expresses. It is, nevertheless, probable that the Sanskrit writers would not have made use of so many of these exotic denominations if the ideas they represent had already found their expression in the languages of India.

Further, among the fine Siddântas which Varâaha-Mihira