ssels were beaten to pieces. Now the "Sailing Directions," which are
the mariner's guide, enable him, from the direction of the winds and
the known laws of motion of the storm centre, to sail out of the
danger, so that in most cases he may escape calamity. It is otherwise
with the people who dwell upon the land over which these atmospheric
convulsions sweep. Fortunately, where these great whirlwinds trespass
on the continent, they quickly die out, because of the relative lack
of moisture which serves to stimulate the uprush which creates them.
Thus in their more violent forms hurricanes are only felt near the
sea, and generally on islands and peninsulas. There the hurricane
winds, by the swiftness of their movement, which often attains a speed
of a hundred miles or more, apply a great deal of energy to all
obstacles in their path. The pressure thus produced is only less
destructive than that which is brought about by the tornadoes, which
are next to be described.

There is another effect from hurricanes which is even more destructive
to life than that caused by the direct action of the wind. In these
whirlings great differences in atmospheric pressure are brought about
in contiguous areas of sea. The result is a sudden elevation in the
level of one part of the water. These disturbances, where the shore
lands are low and thickly peopled, as is the case along the western
coast of the Bay of Bengal, may produce inundations which are terribly
destructive to life and property. They are known also in southern
Florida and along the islands of the Caribbean, but in that region are
not so often damaging to mankind.

Fortunately, hurricanes are limited to a very small part of the
tropical district. They occur only in those regions, on the eastern
faces of tropical lands, where the general westerly set of the winds
favours the accumulation of great bodies of very warm, moist air next
the surface of the sea. The western portion of the Gulf of Mexico and
the Caribbean, the Bay of Bengal, and the southeastern portion of Asia
are especially liable to their visitations. They sometimes develop,
though with less fury, in other parts of the tropics. On the western
coast of South America and Africa, where the oceans are visited by the
dry land winds, and where the waters are cooled by currents setting
in from high latitudes, they are unknown.

Only less in order of magnitude than the hurricanes are the circular
storms known as cyclones.