Raphael Semmes, Memoirs of Service Afloat During the War Between the States

[728] now to give place to an indraught toward the Great Deserts. The south-east wind, thus encouraged, changes its course, first to the north, and then to the north-east, and blows stronger and stronger as the season advances, and the heat accumulates over the deserts; until at last the south-east trade-wind of the southern hemisphere has become the south-west monsoon of the northern hemisphere! This monsoon prevails from about the 1st of May to the 1st of November, when the sun has again passed into the southern hemisphere, and withdrawn his heat from the great deserts. The normal condition of things being thus restored, the vanquished north-east trade-wind regains its courage, and, chasing back the south-west monsoon, resumes its sway.

If the reader will again cast his eye upon the sketch, he will see that the south-west winds which are now blowing over Hindostan, instead of being dry winds, must be heavily laden with moisture. They have had a clean sweep from the tropic of Capricorn, with no land intervening between them and the coast of Hindostan. They have followed the sun in his course, and under the influence of his perpendicular rays have lapped up the waters like a thirsty wolf. The evaporation in these seas is enormous. It has been stated, on the authority of the Secretary of the Geographical Society of Bombay, that it has been found in the Bay of Bengal to exceed an inch daily. From having too little water during the winter months in Hindostan, we are now, in the summer months, in danger of having too much. The young cotton crop will be drowned out. What is to prevent it? Here we have another beautiful provision at hand. The reader has observed the Ghaut Mountains stretching along parallel with the west coast of Hindostan. These mountains protect the plains from inundation. They have, therefore, equally important functions to perform with the deserts. The south-west monsoon blows square across these mountains. As the heavily laden wind begins to ascend the first slopes, it commences to deposit its moisture. Incessant rains set in, and immense quantities of water fall before the winds have passed the mountains. The precipitation has been known to be as great as twelve or thirteen inches in a single day! The winds, thus deprived of their excess of water