in the following tables, the figures at the top indicating stations 

 and those at the left the dates : 



1909 



Evaporation from pans 





Relative 



Aug. 



1 2 



3 



4 5 



6 



Humidity 



6 



97 cc. 85 cc. 



74 cc. 



11 cc. 0 cc. 



Occ. 



.55 - .78 



7 



49 cc. 65 cc. 



39 cc. 



16 cc. 9 cc. 



Occ. 



.59- .81 



8 



18 cc. 4 cc. 



15 cc. 



0 cc. 0 cc. 



0 cc. 



. 72 - . 91 



9 



48 cc. 45 cc. 



48 cc. 



8 cc. 26 cc. 



Occ. 



.50- .97 



10 



100 cc. 100 cc. 



77 cc. 



0 cc. 67 cc. 



Occ. 



.55- .84 



11 



97 cc. 96 cc. 



63 cc. 



8 cc. 28 cc. 



Occ. 



.53- .87 



At the same time the 



record of temperature, of ^^-ind, and of 



sky was as follows, the wind velocity being 



given in 



miles per 



hour: 













Aug. 



Temperature 



Wind Tel. Wind Direction 



Sky 



6 



75° -88° 



7 -Id 



S. 



Clear 



7 



70° -83° 



6-13 



S.; S. E. 



Hazy 



8 



74° -82° 



0-10 



S., W., X. W. Cloudy 



9 



70° -92° 



Gusts 



S.E., S., 



S.W. Cloudy 



10 



77° -91° 



0-13 



s., w. 



Clear 



11 



81° -94° 



0-14 



s. 



Some clouds 



The great variation in evaporation is especially striking, and 

 seems to be greater than might be expected from the more lim- 

 ited variation in relative humidity. 



On the cloudy days, Aug. 8th and 9th, there was a distinct 

 diminution in evaporation, due in part also to reduced wind ve- 

 locity. Stations 1 and 2 Avere most exposed and on the whole 

 showed the highest evaporation, especially when the wind was 

 from the southwest on a clear day. The amount of evaporation 

 at station 3 was surprisingly great, inasmuch as the station was 

 located near the lake on one of the strips of prairie which here 

 reach the edge of the lake bluff. This station is somewhat ex- 

 posed to the west and southwest, and to the southeast. When 

 the prevailing direction of the wind was from the southwest, and 

 the lake vapors were carried away from this shore, the rate of 

 evaporation was high. 



The results at station 5 are also interesting. This station 

 faced the lake and was only a few feet from the water. When 

 the wind was from the southwest evaporation was greatest, as on 



23 



