NO. lO STORM FREQUENCY IN THE UNITED STATES — KULLMER 5 



weakened. Again my original period is the best. In the third period, 

 figure 17, the northern plus band is weakened; otherwise, there is 

 little choice. The fourth period, figure i8, shows the greatest dis- 

 crepancy, with a great weakening of the northern minus band and 

 the introduction with the year 1916 of a new strong plus band. There 

 is also a weakening of the southern plus curve. It is evident that for 

 the solar influence presented in this paper my original period is far 

 the superior. The last period, figure 19, shows a widening and 

 strengthening of the northern minus band and I have consequently 

 chosen it as the best representative of the three-banded effect. Why, 

 with this one exception, my original periods best bring out the solar 

 eft'ect here presented I cannot venture an opinion ; it is, however, 

 of interest, that with the exception of the fourth period, a shift of 

 I year, and in one case, of 2 years does not vitiate the results. 



These, then, are my findings, and I offer them to those more com- 

 petent than I am for interpretation. 



I append the year maps of storm frequency for 1931-1940, form- 

 ing a series of 58 year maps, made with care according to a uniform 

 technique, to which can be added the years 1874-1882, now in manu- 

 script. 



