If space permitted, an
interesting statement could he made of the changes which have taken
place in vegetation in Greenland, and throughout certain northern
parts of Europe,--also in Palestine, Greece, and other southern
countries,--while we know that the earth's inclination upon its axis
has been unchanged.
Mrs. Somerville remarks, that, though the temperature of any one place
may be subject to very great variations, yet it never differs from the
mean state more than a few degrees.
Without this atmospheric covering of ours, it is considered that the
temperature of the earth at its surface would be the same as that of
the celestial spaces, supposed to be at least 76 deg. below zero, or
_possibly_, says Humboldt, 1400 deg. below! Human life, without our
atmosphere, could not exist for a single moment.
It is computed, that, if the annual heat received by the earth on its
surface could be equally distributed over it, it would melt, in the
course of a year, a stratum of ice 46 feet thick, though it covered
the whole globe, and as a consequence the amount of unradiated heat
would render it uninhabitable.
The relative position of the sun affects temperature, rather than its
distance.
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