Some years ago it was suggested to me to undertake an edition and translation of the Súrya Siddhánta; but a long and careful study of the work convinced me that it would be impossible satisfactorily to accomplish the object without more assistance than was to be found in Europe. The MSS. were few and insufficient in accuracy; the lexicon was deficient in most of the technical terms; and the only works that threw any light upon the subject were those of Colebrooke, invaluable as far as they went, and the Abbé Guérin's Astronomie Indienne. The other writers who had touched upon the subject merely reproduced what was to be found in Colebrooke.