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

THE GLACIAL PERIOD. 25
time is indubitably proved, yet scientific men have not been as
yet able to trace satisfactorily the causes of this great catastrophe.
Such immense mass of ice as covered the whole of Northern
Europe and America during this period could not, like anything
else, come out of nothing. There must be heat enough in certain
parts of the globe to create by evaporation sufficient vapour, and
aerial currents are required to transfer it to the colder regions
of the globe, there to be precipitated in the form of ice. Any
theory regarding the cause of the Ice Age which fails to take
this fact into account is not only inadequate but worthless. A
succession of Glacial periods, or, at any rate, the occurrence of
two Glacial periods, must again be accounted for by the theory
that may be proposed to explain these changes; and if we test the
different theories advanced in this way, many of them will be at
once found to be untenable. It was, for instance, once urged that
the Gulf Stream, which, at present, imparts warmth to the
countries in the North-West of Europe, might have been turned
away from its course in the Pleistocene period by the submergence
of the Isthmus of Panama, thus converting the countries on the
North-Western coast of Europe into lands covered by ice. There
is, however, no geological evidence to show that the Isthmus of
Panama was submerged in the Pleistocene period, and we must,
therefore, give up this hypothesis. Another theory started to
account for the catastrophe was that the earth must have
passed through cold and hot regions of space, thus giving rise to
Glacial and Inter-Glacial periods respectively. But this too is
unsupported by any evidence. A third suggestion advanced
was that the supply of solar heat on earth must have
varied in such a way as to give rise to warm and cold
climates but this was shown to be a mere conjecture. A
change in the position of the earth's axis might indeed cause
such sudden changes in the climate; but a change in the
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