A REPRESENTATION OF THE SUNSPOT CYCLE 299 



responsible for the eleven-year periodicity of sunspots has an ampHtude 

 of only about 2/5 of the greatest amplitudes of the resultant maxima. 

 Next in importance are the two adjacent periods at 17.3 and 18.4 

 years, respectively. 



In conclusion, the study has resulted in a representation of yearly 

 sunspot averages which agrees as well as could be desired with the 

 data and which is also consistent with the reported times of maxima 

 and minima back as far as 1610 a.d. The chief component has been 

 treated as a 22-year (22.25 years) component instead of eleven years. 

 In the course of computation the components appeared to be har- 

 monics, or nearly so, of a 312-year period. A substantiation of this 

 312-year cycle' was found in a check of the overlapping data (maxima 

 and minima from 1923 to date). 



It had been hoped that the resultant distribution of amplitudes 

 versus frequency of the components might be capable of simple inter- 

 pretation and that a rather simple explanation of the phenomena of 

 sunspot periodicity might result, such as one or two forces acting 

 upon a nonlinear system with a given fundamental period. Further 

 studies may still indicate this to be the case. 



The author wishes to express his appreciation of the assistance of 

 Miss Helen Grant with the rather tedious computations. 



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