156 



THE PHYSICAL GEOGKAPHY OF THE SEA. 



uny one of these bands must have moved in a path crossing these 

 bands more or less obliquely, and that therefore the general move- 

 ments in the atmosphere might be classed accordingly, as winds ei- 

 ther with northing or with southing in them. We have so classed 

 them ; and we have so classed them that we might study to more 

 advantage the general movements of the great atmospherical ma- 

 chinery. See Plate XV. 



853. Thus, when, after so classing them, we come to examine 

 The medial bands, thosc movcmcnts in the band between 5° and 10° 

 south, and to contrast them with the movements in the band be- 

 tween 55° and 60° south, for example, we find the general move- 

 ments to be exactly in opposite directions. Observations show 

 that during the year the winds in the former blow toward the 

 equator 283, and from it 73 days ; and in the latter they blow 

 toward the pole for 224, and from it 132 days. These facts show 

 that there must be a place of rarefaction — of low barometer, an in- 

 draught toward the poles as well as the equator, and that conse- 

 quently, also, there must be a medial line or band somewhere be- 

 tween the parallels of 10° and 55° south, on one side of which the 

 prevailing direction of the wind is toward the equator, on the 

 other toward the pole. So, in the northern hemisphere, the same 

 series of observations point this medial band out to us. They show 

 that one is near the calm belt of Capricorn, the other near the 

 calm belt of Cancer, and that they both probably lie between the 

 parallels of 35° and 40°, where the winds north and south are 

 equal, as per table. 



Winds with Northinj and Winds ivith Sottthmg in each Hemisphere, expressed hy the 

 Average Number of Days for lohich they hloio annually. 



