, for the most part,
_deflected trade-winds_. And they owe their deflection to the presence
of large continents. If there were no land near the equator, the
trade-winds would always blow in the same manner right round the world;
but the great continents, with their intensely-heated surfaces, cause
local disturbance of the trade-winds. When a trade-wind is turned out
of its course, it is regarded as a monsoon. For instance, the summer
sun, beating on the interior plains of Asia, creates such intense heat
in the atmosphere that it is more than sufficient to neutralise the
forces which cause the trade-winds to blow. They are, accordingly,
arrested and turned back. The great general law of the trades is in
this region temporarily suspended, and the monsoons are created.

It is thus that the heated plains of Africa and Central America produce
the monsoons of the Atlantic, the Pacific, and the Gulf of Mexico.

We think it unnecessary to explain minutely the causes that produce
variation in the monsoons. Every intelligent reader will readily
conceive how the change of seasons and varied configuration as well as
unequal arrangement of land and water, will reverse, alter, and modify
the direction and strength of the monsoons.

Land and sea breezes are the next species of wind to which we would
direct attention. They occur in tropical countries, and owe their
existence to the fact that the land is much more easily affected by
sudden changes of temperature than the sea. Thus, the land in warm
regions is much heated by the sun's rays during the day; the atmosphere
over it becomes also heated, in virtue of which it rises: the cool
atmosphere over the sea rushes in to supply its place, and forms the
_sea breeze_: which occurs only during the day.

At night the converse of this takes place. Land heats and cools
rapidly; water heats and cools slowly. After the sun sets, the cooling
of the land goes on faster than that of the sea. In a short time the
atmosphere over the land becomes cooler than that over the sea; it
descends and flows off out to sea; thus forming the _land breeze_. It
occurs only at night, and when the change from one to the other is
taking place there is always a short period of calm. Land and sea
breezes are of the greatest use in refreshing those regions which,
without them, would be almost, if not altogether, uninhabitable.

In "The Tempest," an interesting work on the origin and phenomena of
wind