nd a certain point it is
so cold, that neither men nor any other animals can exist. This can be
proved in several ways; and the experience of those who have climbed
mountains, only three miles high, confirms it. Some of these
adventurous men have been nearly frozen to death. This is a fact, then,
in regard to the atmosphere over all parts of the earth; but we may also
observe, that under the Equator you may go higher without reaching this
extreme cold, than in the countries which lie nearer to the Poles.
Another fact, which you will easily believe, is, that in summer you can
climb higher before you reach the cold region than in winter. Bear
these facts in mind. Now, then, if it be so cold at a certain height
that men would be frozen to death, of course at that height snow will
not melt. What is the natural inference? Why--that mountains whose
tops pierce up into this cold region will most certainly be covered with
perpetual snow. It is not likely that anything but snow ever falls upon
their summits,--for when it rains upon the plains around them, it is
snowing upon the high peaks above. Indeed, it is probable that most of
the rain which descends upon the earth has been crystals of snow when it
commenced its descent; and, afterwards melting in the lower and warmer
regions of the atmosphere, takes the shape of water globules, and thus
falls to the ground. These globules, no doubt, are very small when they
first emerge from the snow region; but, as they pass slowly downward
through clouds of vapour, they gather together and attract others (by a
law which I have not time to explain); and, descending faster and
faster, at length plash down to the earth in large drops. Whenever it
rains, then, at any particular place, you may be almost certain that it
is snowing at the same time over that place--only at a point in the
atmosphere far above it. I have been convinced of this fact, by
observing that immediately after every occasion when it has rained in
the valley, there appeared a greater quantity of snow upon the mountain.
Had the mountain not been there, this snow would have continued on, and
become rain, like that which fell upon the plains, and into the valley.'

"`Then, mamma,' interrupted Frank, `this mountain must be of great
height, since the snow lies upon it all the year.'

"`Does that follow?'

"`I think so. You said the snow did not melt because it was cold high
up.'

"`But suppose you were in a coun