24 
COLORADO EXPERIMENT STATION. 
TABLE XIII. 
Lee Lake— 1896. 
Lee Lake— 1897. 
Month. 
Evaporation 
—Inches . 
No. Days 
Record . 
Month. 
Evaporation 
— Inches. 
No. Days 
Record . 
May 
4.31 
24 
June 
15 
June 
9.55 
21 
July 
9.11 
32 
July 
8.53 
21 
August 
7.2.') 
31 
August 
8.61 
32 
September 
5.20 
32 
September 
8.40 
31 
October 
4.17 
28 
October 
4.60 
32 
Loomis Lake— 1897. 
Claymore Lake— 1897 . 
May 
7.89 
20 
May 
5.22 
14 
June. 
7.91 
26 
June 
July 
11.87 
20 
July 
August 
9.02 
32 
August 
8^93 
io 
September 
September 
4.81 
21 
October 
1.89 
32 
October 
1.62 
23 
Warren’s Lake— 1889. 
Warren’s Lake— 1890. 
May 
May 
7.71 
13 
June 
June 
8.40 
7 
July 
i',31 
37 
July 
5.41 
29 
August 
-August 
8.06 
38 
September 
7^25 
30 
September 
October 
5.61 
21 
October 
§ 29. It will be noticed that the evaporation from the tanks as 
given is much greater than the corresponding tank on the grounds 
of the Agricultural College. This difference is partially but not en- 
tirely due to temperature. The tanks in the lakes are more freely 
exposed to the wind than the standard tank, and this would there- 
fore make a great difference. The tanks are more or less agitated by 
waves, and in consequence the water surface exposed to the air is 
larger than the cross section of the tank. A film of water is also 
left on the metal sides of the tank with every movement, and this is 
apt to be of higher temperature than the water in the lake or in the 
tank, and evaporates more rapidly. The influence has been noticed 
by Mr. Trimble, who made the observations in 1896 and some of those 
in 1897, and suggested as a cause of some of the excess of evapora- 
tion observed from the lakes. The effect may be considerable, but 
how much is uncertain. The wave action differs in the different 
lakes. In Lee lake the weeds extend so near the surface that there 
is little opportunity for wave formation. In the other two lakes the 
effect is greater. As the wave also increase the area of the surface 
of the lakes which is exposed to the air likewise, the result is possi- 
bly closer to the loss from a lake exposed to the wind than if the 
tank had been stationary. 
§ 30. The effect of such increase of surface may be considerable. 
We have made no experiments to determine the possible effect. The 
only ones reported are some by Maurice Aymard, a French engineer 
stationed in Algeria, whose report on Irrigation in Spain as prelimi- 
