SMITHSONIAN MISCELLANEOUS COLLECTIONS 



VOL. 80 



mentioiied by many authors as associated with weather and crop 

 harvests.^ 



The period 77/5, or 15! months, is approximately equal to that 

 which Professor Dinsmore Alter has been discussing as ^ the sun- 

 spot period, in his publications on world precipitation. It appears 

 also in its " overtones " of ^ and ^ period. 



Finally there is the period of 77/7, or 11 months, which Clayton 

 and I called attention to several years ago" as occurring in the solar 



L97 



1.96 



1.95 



1.94, 



133 



'■^^O^ 20 AO to 80 100 720~ KO TtO /SO 200 



Fig. 4. — Increased sun-spot activity lirings higher solar constant values. 



radiation. Periods approximating this are also noted by several au- 

 thors in weather phenomena.^ An " overtone " of l- the period of 11 

 months is also distinguishable. 



With his synthesizing machine, Dr. Miller built up the top curve 

 of figure 5, and exterpolated it for several months beyond the data 

 furnished him. Thus far the results from Montezuma have agreed 

 well with this forecast of Dr. Miller which foretold a sharp rise 

 of the solar constant. If, in the next few years, it should be found 



' See Brunt, Quart. Journ. Roy. Met. Sec, Vol. 53, p. 16. and others. 

 ' See Smithsonian Misc. Coll., Vol. 77, No. 5, p. 9, 1925. 

 ^ See Brunt, just cited, page 23. 



