NO. 10 SOLAR RADIATION AND WEATHER STUDIES ABBOT 



15 



was ventured. The average of residuals between predicted and ob- 

 served values is 0.0071 calorie, or 0.37 percent. Although maxima 

 and minima are well placed, there is a decided separation of the curves 

 near the end in figure 8. This is cured in figure 7, and in that figure 

 the average deviation for the curves thus far observed is reduced to 



1932 



1933 



1934 



1935 



Fig. 8. — Predicted and observed solar variation. The maxima and minima 

 occur in the two curves at nearly identical phases. The observed curve may be 

 faulty in 1932 owing to the Chilean volcanic eruption. The separation of the 

 curves toward the end is due to a 23-year periodicity not taken account of. 



0.0036 calories, or 0.19 percent. As explained in caption 26, on 

 page 86, there may possibly be a change of phase in solar variation 

 about 1934, tending to modify the 3-year forecast given in figure 7. 



II. WEATHER RESPONSIVE TO PERIODIC SOLAR CHANGES 

 8. Sun-Spot Influence 



Having strong indications of 12 long-continued periodic fluctua- 

 tions in solar radiation, statistical studies were made to seek for their 

 effects on temperature and precipitation. First taking the departures 



