Ordinary Stornis. 



571 



as that of the direction of the general earth currents, that 

 is, the form and rotation of the earth. As the air leaves 

 the equator it passes over land moving eastward slower 

 than it and hence outruns, appearing to blow from the 



Fio. 265. Diagram of surface winds In a typical cyclone. (After Ferrel.) 



S. W. toward the N. E. in the northern hemisphere, and 

 from the 1ST. W. toward the S. E. in the southern hemi- 

 sphere. If it approaches the equator it travels over land 

 moving eastward faster than it does and hence appears to 

 come from the N. E. in the northern hemisphere and from 

 the S. E. in the southern. 



Where the wind approaches the center from the east it 

 can only do so by having its eastward motion with the earth 

 made slower than the earth's surface in the same latitude ; 



