Again, within this trade-wind region are the _rainless countries_. These are portions of the earth which the equatorial rainy belt does not ascend far enough north in summer to cover, nor does the southern edge of the extra-tropical regular rains descend, in winter, far enough south to cover them, and where, of course, rain seldom, if ever, falls. Such are the central parts of the Desert of Sahara, Egypt, Arabia, portions of Affghanistan, Beloochistan, and the western parts of Hindoostan, to the north of the inter-tropical belt, and a similar state of things exists south of the equator in parts of South America, Africa, and New Holland, although upon a comparatively small surface. Again, another anomaly is the gathering of the trade winds into greater volumes, on the westerly side of the great oceans, and the consequent carrying of the equatorial rainy belt up to the region of extra-tropical rains, on the eastern side of the great continents of Asia and North America, and the peculiar liability of these aerial gulfs to hurricanes and typhoons. Such an aerial gulf gathers over the Caribbean Sea, and the West Indies. Passing across the Gulf of Mexico, it enters over Texas, and Louisiana, and the other southern states; its western edge passing north in autumn and winter, on the eastern side of the highlands of Western Texas, New Mexico, and the Great Desert; curving, as all counter-trades do, to the eastward as soon as it passes the limit of the N. E. trades, and spreading out over our favored country, leaving the evidence of its pathway in the greater quantities of rain, which fall annually upon its surface. This gathering deprives a portion of the Atlantic, north of the tropics, of its share of the counter trade, and there, as every where, where the volume of counter-trade is small, storms and gales are infrequent, and of less force, and comparative calms prevail. That portion of the Atlantic has long been known as "the horse latitudes," a name given to it by our Yankee sailors, because, there, in former times, the old-fashioned, low-decked, flat-bottomed, horse-carrying craft of New England, bound for the West Indies, often floundered about in the calms and baffling winds, until their animals perished for want of water, and were thrown overboard. Lieutenant Maury, in his most praiseworthy and exceedingly useful investigation of "The Winds and Currents of the Ocean," has defined the situation of these calms and baffling winds at different seasons--for they move up and down, of course, with the motion of the whole machinery--and enabled navigators to avoid them, by running _east_ before they attempt to make _southing_; and very materially shortened the voyages to the equator.