CYCLONIC STORMS IN TEMPERATURE LATITUDES 509 



the storminess 99.8 per cent. Years of few as well as many sun-spots 

 are, of course, included in both cases. Nevertheless there is a difference 

 between the two cycles, as may be seen in figure 8. Here, just as in the 

 other cases, we see a belt of increased storminess at the north, with a 

 southward projection in its center. The deficiency in the central portion 

 of the United States is more marked than in the other maps and extends 

 more distinctly into the Pacific Ocean. Yet, as in the other cases, it is 

 most pronounced toward the east and the west and almost disappears in 

 the center. Finally, in the south there is a well defined, although not 

 very intense, belt of increased storminess at times of sun-spot maxima. 

 The only feature of the other maps which does not appear is the most 

 southerly belt of decreased storminess. A similar comparison of the 

 cycle from 1878 to 1888 with the succeeding cycle, 1889 to 1900, shows 

 the same general features for the area east of the 100th meridian, which 

 is as far as data are available. Even the southern belt of deficiency is 

 faintly apparent. 



The resemblances of all these maps apparently lead to the conclusion 

 'that we are dealing with a phenomenon which repeats itself regularly 

 with every repetition of the solar cycle. Not only does the number of 

 storms seem to vary in harmony with the number of sun-spots, but also, 

 and much more markedly, there is a pronounced shifting of the area of 

 storminess. The shifting is so regular that we can not avoid the conclu- 

 sion that Kullmer has discovered one of the important laws of nature. 

 Other investigators, such as Bigelow,^^ have noted that the location of 

 storm tracks and the occurrence of cold waves have a relationship to sun- 

 spots ; but it has remained for Kullmer to put the matter into such form 

 that we can definitely speak of the law of the shifting of storm tracks in 

 harmony with changes in the intensity of solar activity. The meaning 

 of Kullmer's law may be summed up briefly. The great area of excessive 

 storminess in southern Canada means that when sun-spots are numerous 

 the main storm belt shifts northward. This is the point on which Kull- 

 mer most strongly insists. I would add that at such times the main 

 storm belt tends to split. The major portion moves northward, while a 

 smaller, but by no means unimportant, portion shifts southward and 

 oceanward. Thus the storminess of the center of the continent is less at 

 times of many sun-spots than at times of few, while southern Canadi^ and 

 a large area in the south and over the ocean become more stormy. If this 

 process went farther it would apparently result in two storm belts — a 

 boreal belt of great severity and a subtropical belt of minor severity. It 



^ Frank H. Bigelow : Studies on the circulation of tlie atmospheres of the sun and of 

 the earth. Monthly Weather Review, 1904. 



XXXVII — Bull. Ghol. Soc. Am., Vol. 25, 1918 



