SUN" SPOTS AND RADIO STETSON" 219 



Near the Equator the sun rotates once on its axis in a period of al- 

 most 241/^ days, whereas in latitude 35° the motion of the spots across 

 the surface indicates that almost 261/2 days are consumed in a single 

 rotation. Spectroscopic observations make it possible to determine 

 the rate of rotation in regions of higher latitudes than those in which 

 the spots appear. In latitude G0° the rotation period is nearly 31 

 days. The continual slipping of the atmospheric layers of lower lati- 

 tude past those of higher latitude must result in the formation of 

 eddy currents favorable to the formation of cyclonic whirls, thus 

 producing sun spots. 



Eas^ L_^:vc^e ^^_^ Lowest 



FiGUEE 5. — Showing reversal in the magnetic polarity of the spots with change in 



cycle 



The mention of sun spots invariably raises the question of a 

 possible connection between the sj)ots on the sun and terrestrial phe- 

 nomena. Some statisticians with an insatiable appetite for correla- 

 tions have attempted to connect with sun spots almost every cycle 

 in world affairs from fluctuations in the New York stock market to 

 the fecundity of rabbits in northern Canada. In the popular mind 

 almost every w^orld catastrophe has sooner or later been attributed 

 to sun spots, from a Florida hurricane to the great World War, both 

 of which, by the way, did not culminate around a sun-spot maximum. 



But, seriously, there are to the scientist certain well recognized 

 phenomena on the earth which pass through cycles whose correlation 

 with the sun-spot cycle is unmistakable. 



