Turning of the Wind. 105 



must consequently be more deflected than the earlier por- 

 tions, therefore we arrive at the conclusion : — The " equa- 

 torial current" passes gradually over from a northern direc- 

 tion into N.W. and W., and the " polar current" from a 

 southern direction into S.E. and E. 



These two cm-rents in the ec-tropical region are constantly 

 alternating, forcing each other out of their way, and passing 

 each other sideways, or hindering each other in their course. 

 Their combined action will explain the remainder of the phe- 

 nomena. We have explained that the " polar current" passed 

 over into an easterly wind, that is to say, the vane turns from 

 S. to S.E. and E., and this play would go on in repetition if the 

 " equatoral current " did not make itself manifest. Its 

 northerly direction, combined with the now easterly one of 

 the polar current, will change, according to the parallelogram 

 of forces, into E.N.E., N.E. and N. ; and the " equatorial 

 current " from the north passes over into N.W. and W., and 

 the " polar current " will change the direction of the vane 

 again into W.S.W., S.W. and S. Between N. and W. and 

 S. and E. are the critical points in this course of the vane, 

 as here the currents are " contending," and the vane is more 

 frequently thrown back, while within the quadrants between 

 S. and W. and N. and E. the revolution is rapidly accom- 

 plished. If we now comprehend all that has been said with one 

 retrospective glance, we shall arrive at the following law : — 



The phenomena of wind in their " chief features," as they 

 occur within the centrical or ec-tropical system, can be ex- 

 plained by the combined action of two currents, which gra- 

 dually move the vane from S. towards S.E., E., N.E., E., N, 

 N.W., W., S.W. and S., that is to say, " with the sun."* 



S.E. and N.W. are in this course of the revolution the 

 critical quadrants. 



This is the law of the turning of the wind, as laid down by 

 Dove, for the southern hemisphere, and it is for observers 

 impartially to collect facts which would either contradict or 

 prove the accordance between the real and the theoretical 

 speculations. The difficulty of the task has been considerably 

 aggravated by a constant misunderstanding of the principles of 

 Dove's Law. The law of storms, whirlwinds, and cyclones has 

 been constantly confounded with the same, and results of ob- 

 servations were quoted as contradicting its principles, which, 



* In the northern hemisphere the contrary takes place, the vane moving 

 from N. toward E.. S. . W. . N". . or also " with the. sun." 



