ic is perfectly still, the
sea calm as glass, and the vessel floats motionless with her sails
hanging idly from the yards, as if she were:

A painted ship upon a painted Ocean.

Suddenly, and before preparation can be made to withstand it, the
hurricane bursts in appalling fury over the sea: the sails are blown to
ribbons; the masts, perhaps, broken down; and frequently the vessel
itself overwhelmed and sent to the bottom. Many a gallant ship, which
has left the harbour ably commanded and well manned, and never more been
heard of, has doubtless gone down in sudden storms such as those we have
referred to.

But the inventions of science have now very much lessened the danger of
these storms. The barometer, by the sudden fall of its column of
mercury, tells, as plainly and certainly as if it spoke with an audible
voice, that a storm is approaching, even though all nature should appear
to contradict the fact by its calm and serene aspect; so that the crew
thus warned have time to furl the sails, fasten down the hatches, and
otherwise prepare to face the impending danger.

The atmosphere flows in a grand harmonious system of currents and
counter-currents, with their corresponding eddies, just like the ocean;
and the grand final results of its varied action are to equalise in some
degree the temperatures of the world, to carry off and distribute
moisture where it is required, to sweep away noxious vapours, and
generally to ventilate the Earth and gladden the heart of man.

The primary cause of all wind is the combined action of heat and cold.
If the world were heated with perfect equality all round, there would
be, as far at least as heat is concerned, a perfect and permanent
stagnation of the atmosphere; and this would speedily result in the
destruction of every living thing. But by the varied and beautiful
arrangements which the Almighty has made in nature He has secured a
regular flow of atmospheric currents, which will continue unalterably to
move as long as the present economy of things exists. The intense and
constant action of the sun's rays in the torrid zone produces great
heat, while the less powerful and frequently interrupted influence of
his rays in the frigid zones induces extreme cold. Hence we have in one
region heated air, in another cool air. Now, the effect of heat upon
air is to expand it, make it light, and cause it to rise. The moment it
does so, the cold air rushes in to supply its place;