THE ANTARCTIC REGIONS AND THEIR CLIMATOLOGY. 



453 



the propriety of excluding all regions which are known to pre- 

 sent exceptional cases to the general law. The grouping was not 

 carried beyond lat. 60° north and south, for the lack of observa- 

 tions on the polar side of those parallels. The number of obser- 

 vations thus becoming available was 1,159,353. These were 

 then divided simply into two classes for each belt, viz., polar 

 winds* and equatorial winds. They were then reduced to terms 

 of a year, and the average prevalence of each wind in days de- 

 duced therefrom, as per Plate XV., and the following table : — 



Polar and Equatorial Winds. 



852. The null belts. — This plate and table reveal a marked 

 difference in the atmospherical movements north, as compared 

 with the atmospherical movements south of the equator. The 

 equatorial winds of the northern hemisphere are in excess only 

 between the parallels of 10° and 30°; i. e., they are the dominant 

 winds over a zone 20^ of lat. in breadth, while the equatorial 

 winds of the southern hemisphere hold the mastery from 35° S. 

 to 10° N. ; {. e., they are the dominant winds over a zone 45° of 

 lat. in breadth, while the others cover a space not half so broad. 

 This table, moreover, shows the debatable ground between the 

 winds, or what may be called the null helty in this general move- 

 ment from poles towards the equator, and from equator towards 



* Polar winds blow toicard the pole, equatorial toward the equator. 



