UTILIZATION OF SOLAR ENERGY ACKERMANN, 



143 



The absorption of solar energy by the atmosphere is about 20 per 

 cent gi-eater in summer than in winter. This may be due to there 

 being a larger total quantity of water vapor in the atmosphere in 

 summer than in winter. It has long been known that the greater the 

 humidity of the atmosphere the greater the amount of heat stopped 



SUN POWEfi PL/^NT /JT ME/JO/. £CYPr, /i'/J 

 Curves shonin4j effect of hiunulit^ on steam ^odcutwn 



O^ *f ^*'4»-»s(yB 



HUMIDITY PER CENT 



Fig. 1. 



by it; but the author believes that his experiments in Egypt in 1913, 

 with the Shuman-Boys sun-power plant, were the first which de- 

 termined the quantitative effect of humidity, especially on so large a 

 scale. The curves on figure 1 record the results, from which it is 

 seen that when the humidity decreased 20 per cent the quantity of 



