NO. 5 



SOLAR VARIATION AND FORECASTING ABBOT 



23 



-tooo 



Fig. 15.— Variation of the sun, March to May, 1920. The lower curve (scale 

 at the left) gives values of the " solar constant of radiation " observed by 

 Smithsonian men at Calama, Chile. The upper curve (scale at the right) gives 

 areas, in millionths of solar hemisphere, of calcium flocculi, measured at the 

 Observatory of Ebro in Spain. Only flocculi within ±15° of the central solar 

 meridian are included. Two scales of days are given, as the upper curve is 

 displaced i day forward. Coincident depressions are indicated by letters. 



Fig. 16. — Central sun spots and solar radiation. The lower curve is from 

 publications of the observatory at Ebro. 



