The orientalists who exploited Indian history and literature about a century ago were not always perfect in their methods of investigation and consequently promulgated many errors. Gradually, however, sounder method have obtained and we are now able to see the facts in more correction perspective. In particular the early chronology has been largely revised and the revision in some instances has important bearings on the history of mathematics and allied subjects. According to orthodox Hindu tradition the Surya Siddhanta, the most important Indian astronomical work, was composed over two million years ago! Bailly, towards the end of the eighteenth century, considered that Indian astronomy had been founded on accurate observation made thousands of years before the Christian era. LAPLACE, basing his arguments on figures given by BAILLY considered that some 3,000 years B.C. the Indian astronomers had recorded actual observations of the plants correct to one second; PLAYFAIR eloquently supported BAILLY’S views; Sri WILLIAM JONES argued that correct observations must have been made at least as early as 1181 B.C.; and so on; but with the researches of COLEBROOKE, WHITNEY, WEBER, THIBAUT, and others more correct view were introduced and it was proved that the records used by Bailly were quite modern and that the actual period of the composition of the original Surya Siddhanta was not earliar than A.D. 400.