162 PHYSICAL GEOGRArHT OF THE SEA, AND ITS METEOROLOGY. 



Winds with NortJung and Winds icith Southing in each Hemisphere, expressed 

 Jry Average Numher 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 de- 

 cided. 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 con- 

 dition 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 

 YIII.), 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 " dr?/ 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 

 * § 273, p. 614, vol. xvii. (Phys. Geog.), Encyclopaedia Britannica. 



