Page:Physical Geography of the Sea and its Meteorology.djvu/188

162 Winds with Nothing and Winds with Southing in each Hemisphere, expressed by Average Number of Days for which they blow annually.

crossing, between 35° and 40°. In the southern hemisphere, the conflict between the polar and equatorial indraught, as expressed by winds with southing and winds with northing, is more decided. There the two curves march, one up, the other down, and cross between the parallels of 35° and 40° S., thus confirming what from other data we had already learned, viz., that the condition of the atmosphere is more unstable in the northern than it is in the southern hemisphere.

354. The rainless regions and the calm belts.—Such, for the winds at sea, is their distribution between the two halves of the horizon in the several bands and in each hemisphere. Supposing a like distribution to obtain on shore, we shall find it suggestive to trace the calm belts of the tropics across the continents (Plate VIII.), and to examine, in connection with them, the rainless regions of the earth, and those districts of country which, though not rainless, are nevertheless considered as "dry countries," by reason of the small amount of precipitation upon them. So, tracing the calm belt of Cancer, which at sea lies between the parallels of 28° and 37° (Plate VIII.), but which, according to Sir John Herschel, reaches higher latitudes on shore, it will be perceived that the winds that flow out on the north side blow