वेदों की प्राचीनता एवं काल-निर्णय / ओरायन (लोकमान्य बाल गंगाधर तिलक - खगोलीय वैदिक शोध)

THE GLACIAL PERIOD. 35 about a Glacial period; and it may, therefore, be well urged that a Glacial epoch may occur even when the eccentricity is not at its maximum. Another point in which Dr. Croll's theory conflicts with the geological evidence is the date of the close of the last Glacial epoch, as ascertained, by the American geologists, from estimates based on the erosion of valleys since the close of the last Glacial period. It is pointed out in the last chapter that these estimates do not carry the beginning of the Post-Glacial period much further than about 10,000 years ago at the best; while Dr. Croll's calculation would carry it back to 80 or 100 thousand years. This is a serious difference, and even Prof. Geikie, who does not entirely accept the American view, is obliged to admit that though Dr. Croll's theory is the only theory that accounts for the succession of Glacial epochs, and, therefore, the only correct theory, yet the formula employed by him to calculate the values of the eccentri- city of the earth's orbit may be incorrect, and that we may thus account for the wide discrepancy between his inference and the conclusions based upon hard geological facts, which cannot be lightly set aside.* The judgment recently pronounced by Mr. Hudleston is still more severe. In his opening address, as President of the geological section of the meeting of the British Association in 1898, he is reported to have remarked, "There is probably nothing more extraordinary in the history of modern investigation than the extent to which geologists of an earlier date permitted themselves to be led away by the fascinating theories of Croll. The astronomical explanation of that 'Will-o'-the-wisp,' the cause of the great Ice Age, is at present greatly discredited, and we begin to estimate at their true value those elaborate calculations which were made to account for events, which, in all probability, never occurred. Extravagance begets extravagance, and the

• Fragments of Earth Lore, p. 287.