It is found at last that both the existence of Egypt itself, and its strange insulation in the midst of boundless tracts of dry and barren sand, depend upon certain remarkable results of the general laws of rain. The water which is taken up by the atmosphere from the surface of t...he sea and of the land by evaporation, falls again, under certain circumstances, in showers of rain, the frequency and copiousness of which vary very much in different portions of the earth. As a general principle, rains are much more frequent and abundant near the equator than in temperate climes, and they grow less and less so as we approach the poles. This might naturally have been expected; for, under the burning sun of the equator, the evaporation of water must necessarily go on with immensely greater rapidity than in the colder zones, and all the water which is taken up must, of course, again come down.
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