1914] FULLER— EVAPORATION AND SOIL MOISTURE 213 



For the season of 191 2 the prairie stations were under the efficient 

 charge of Miss L. Newlon, to whom the writer is indebted for the 

 results here presented. During both seasons the range of the 

 evaporation rate was great (figs. 5, 6), the vernal maxima being 

 37 cc. and 27 cc. daily, the midsummer maxima 16 cc. and 16.5 cc. 

 daily; the minima 5.9 cc. and 6. 1 cc; while the average for each 

 of the two seasons was 12.5 cc. per day. 



GENERAL CONCLUSIONS 



em 



means 



the various associations. Perhaps the best is by 

 charts upon which the daily average rate by weeks for all the 

 associations are plotted together (figs. 4, 5, 6). Here the char- 

 acteristics of the different rates are represented graphically, and 

 may be seen at a glance. Throughout the entire series the maxima 

 and minima are generally coincident in time and proportionate in 

 amount. Minor irregularities appear that it would be useless to 

 attempt to explain. The different years show characteristically 

 different curves. Thus, 19 10 comes nearest to the commonly 

 accepted ideas, with a somewhat regular curve increasing rather 

 regularly from the beginning of the growing season, reaching a 

 marked maximum about midsummer, and falling rather sharply 



humid 



gust and September. The follow- 



ing year there are excessively high rates of evaporation in May 

 (%- 5) > which will be found to correspond to a period of unusual 

 weather conditions. The month had the highest temperature 



Weathc 



normal 



May experienced since the establishment 



temperature was io° above 



F. The per- 



centage of sunshine (79 per cent) was also greater than observed 

 during any previous May. Moderate temperature conditions at 



mmer, and a relative humidity 



normal mean 



are reflected in the general course of the evaporation graphs. The 



marked bv a verv moderate 



of the weather bureau showing comparatively light air movement 

 while throughout July, August, and September the temperature 



