=Monsoon Winds.= During winter the vast continent of Eurasia (Europe and Asia) cools to such an extremely low temperature as to develop a High, or center of action, of great energy and extent, which drives a steady dry monsoon into the Indian Ocean and China Sea. Unlike the trade winds, these winds reverse their direction in the summer; then the intense heat of the continent to the north develops an extensive Low, which draws the ocean winds inland and extends its influence so far south as to attract the southeast trade winds of the Southern Hemisphere and, turning them so that they flow from the southwest, continue them far into the interior of Asia. Since the summer monsoon blows from a tropical sea it comes heavily laden with water vapor and as it rises over the mountains of the great Himalayan system copious rains are precipitated. In Australia, Africa, South America, and some parts of the North American continent monsoon influence in various degrees is felt, but in no place is the monsoon so important as in the countries bordering the Indian Ocean. (Charts 15 and 16.) =Föhn Winds.= This is a hot wind that sometimes blows down a mountain side in the Alps. In the Rocky Mountains it is called the Chinook Wind. It is caused by moisture-laden air being drawn over a high mountain so quickly that the heat liberated in condensation does not have time to escape by radiation. The air cools by expansion as it ascends on the west side of the mountain, but it gains this all back by compression as it descends, and it has added to its temperature much of the heat of condensation. It is dry and greedily evaporates snow from the ground in winter, clearing off a deep covering within a few hours. [Illustration: FIG. 14.—How winds would blow into a cyclone on a non-rotating earth.] =How Winds Are Deflected by Earth’s Rotation.= Every free-moving thing, whether wind or projectile, is deflected to the right of its initial direction by the rotation of the earth in the Northern Hemisphere and to the left in the Southern Hemisphere, unless the object be moving exactly along the line of the equator. Winds moving inward to a Low are therefore so deflected as to cause the cyclone to gyrate in a direction contrary to the movements of the hands of a watch. In an anti-cyclone the movement is with the watch. In the Southern Hemisphere these wind directions are reversed.