create waterspouts;
of which we shall have something to say in another chapter. Meanwhile,
we think it may be interesting to give the following miscellaneous
information regarding the atmosphere, gathered from the work of Dr
Buist, who devoted much earnest study to the subject of atmospheric
phenomena.

"The weight of the atmosphere is equal to that of a solid globe of lead
sixty miles in diameter. Its principal elements are oxygen and nitrogen
gases, with a vast quantity of water suspended in them in the shape of
vapour; and, commingled with these, a quantity of carbon in the shape of
fixed air, sufficient to restore from its mass many-fold the coal that
now exists in the world. Water is not compressible or elastic; it may
be solidified into ice or vaporised into steam: but the air is elastic
and compressible. It may be condensed to any extent by pressure, or
expanded to an infinite degree of tenuity by pressure being removed from
it. It is not liable to undergo any changes in constitution beyond
these, by any of the ordinary influences by which it is affected."

If the heating and cooling process--which we have described as being
carried on between the equator and the poles--were to cease, we should
have a furious hurricane rushing perpetually round the globe at the rate
of one thousand miles an hour,--ten times the speed of the most violent
tornado that has ever carried devastation over the surface of the earth.

The air, heated and dried as it sweeps over the arid surface of the
soil, drinks up by day myriads of tons of moisture from the sea,--so
much, indeed, that, were none restored to it, the surface of the ocean
would be depressed eight or ten feet annually.

We do not certainly know the height of the atmosphere. It is said that
its upper surface cannot lie nearer to us than fifty, and can scarcely
be further off than five hundred, miles. "It surrounds us on all sides,
yet we cannot see it; it presses on us with a weight of fifteen pounds
on every square inch of the surface of our bodies--in other words, we
are at all times sustaining a load of between seventy and one hundred
tons of it on our persons--yet we do not feel it! Softer than the
finest down, more impalpable than the lightest gossamer, it leaves the
cobweb undisturbed, and, at times, scarcely stirs the most delicate
flower that feeds on the dew it supplies; yet it bears the fleets of
nations on its wings round the world, and crushes the mos