A monsoon is a wind that blows from a continent toward the sea in winter, when the land is colder than the water, and in the opposite direction in summer, when the reverse conditions of temperature prevail. The pressure gradient is reversed with the seasons, and the wind varies accordingly. The most striking example of monsoon winds is found in southern Asia--where these winds are of special economic importance because they control the rainfall of India--but well-developed monsoons also occur in Australia and West Africa, over the Caspian Sea, on the coast of Texas, and elsewhere. An analogous reversal of gradients, due to the change of temperature over the land from day to night, is of common occurrence on the shores of large bodies of water, resulting in land and sea breezes (or land and lake breezes). The breeze blows from the land to the water by night and in the opposite direction by day. These breezes are generally best developed and most regular within the tropics, and particularly on shores adjacent to mountains. East Indian fishermen put out to sea with the land breeze in the early morning and come home with the sea breeze in the afternoon. The refreshing and health-giving character of the sea breeze of tropical climates has earned it the sobriquet of “the doctor.” Mountain and valley breezes furnish another example of diurnally reversed winds. Relatively cold and heavy air drains down from the upper slopes by night, constituting the mountain breeze. By day the air in the valley is warmed and expanded, and as it is confined laterally by the sides of the valley it flows up the slopes, constituting the valley breeze. Long before meteorologists undertook to classify the winds of the globe, these mountain air currents attracted attention and acquired local names. Among the Alps, alone, we find scores of such names. In many cases, too, the breezes have acquired a legendry of their own. Thus the _pontias_, a cold, nocturnal wind that blows out of a narrow valley opening upon the plains of the Rhône near the town of Nyons, is said to have been brought thither in a glove by St. Cæsarius, Archbishop of Aries, for the purpose of improving the fertility of the valley! There is a quaint little book about the pontias, published by Gabriel Boule in 1647, in which the author sets forth at length the arguments for and against the miraculous origin of this wind. The Italian lakes are especially rich in locally named mountain and valley breezes. Parenthetically it may be remarked that wind nomenclature in general is a vast subject, owing to the habit that prevailed in prescientific times, and still prevails to some extent among nonscientific people, of giving individual names to the winds characteristic of different localities. As a matter of curious interest, we set down here some of these names (a small fraction of the total number):