Page:The ocean and its wonders.djvu/105

 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 neutralize 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