NO. 9 PERIODICITY IN SOLAR VARIATION ABBOT AND BOND 9 



9^ and i8 months are found also at Clanton. The i3|-month periodi- 

 city is new. No appreciable influence of the 1 1 -month solar periodicity 

 is found. 



The results for Williston, N. Dak., are shown in Figure 6. Much 

 wider range of departures is shown by curve A than by the correspond- 



Fig. 5. — Temperature departures, Washington, D. C, and their periodicities. 

 A, original data ; C, 8-month ; D, g-V-month ; E, i3|-month ; F, i8-month ; G, 

 25-month; H, 45-month; I, 68-month; B, residual after removing periodicities, 

 shows I i^^-year periodicity. 



ing curves at Clanton and Washington. Yet, as shown by curve B, this 

 range is reduced nearly to zero by withdrawing the periodic departures 

 discovered. They are shown in curves C, D, E, F, G, H, I, J, K, and 

 L, respectively of 7, 8, 11, 13^, 18, 21, 25, 28, 45, and 68 months 

 periods. The ii^-year period is but indistinctly shown in the residual 



