SECTION OF IRRIGATION AND METEOROLOGY. 
17 
bottom of the lake is cooler than the surface, as was to be expected. 
Table 6 shows the changes during the day at the bottom and surface of 
Lee lake, the measurements being made at fifteen minute intervals 
for eight hours. From hourly observations on the smaller evapora- 
tion tanks at the College, there is reason to believe that late at night 
the bottom and surface become of the same temperature, and that at 
times the bottom is warmer than the surface. 
To show the changes in the temperature of a lake during the 
day the following observations are given. They were made Aug. 6, 
1896, on the Lee lake, by Mr. R. E. Trimble: 
TABLE VI. 
Hour of Obseevation. 
Clouds, 
in 
Tenths. 
1 
Wind. 
Temperature of Water. 
Tank. 
Lake 
Surface. 
Lake 
Bottom. 
y ;00 a. m 
71.0 
70.2 
68.8 
9 : 15 a. m 
Few 
72.0 
70.5 
68.2 
9 : 30 a. m 
Few 
Li^ht 8. E. 
72.0 
70.7 
68.0 
9 : 45 a. m 
Few 
Lights E. 
72.0 
71.2 
67.7 
10 : 00 a . m 
Few 
East. 
72.0 
71.0 
68.0 
10 : 15 a. m 
1 
72 8 
71.7 
68.8 
10 : 30 a. m 
1 
Lierht 8. E. 
73.3 
72.2 
69.0 
10 : 45 a . m 
2 
Idght 8. E. 
74.0 
72.9 
68.6 
11 : 00 a. rn 
2 
Light 8. E. 
74.0 
73 0 
68.5 
11 : 15 a. m 
3 
Light 8. E. 
74.0 
73.0 
68.2 
11 : 30 a. m 
3 
Light 8. E. 
73.2 
72 9 
68.5 
11 : 45 a. m 
3 
Light 8. E. 
74.0 
73.1 
69.1 
12 : 00 p, m 
2 
Lu^ht 8. E. 
74.2 
73.2 
69.2 
12 : 15 p. m 
2 
Light 8. E. 
74.8 
74.0 
68.8 
12 : 30 p. m 
2 
Light 8. E. 
74.4 
74 0 
68.8 
12 : 45 p. m 
3 
Light 8. E. 
74.5 
74.2 
69.1 
1 : 00 p. m 
4 
Light 8. E. 
74.0 
73.9 
68.3 
1 : 15 p. m 
6 
74.2 
74.2 
68.7 
1 : 30 p. m 
7 
Brisk N. 
73.8 
73.8 
69.1 
1 : 45 p. m 
5 
Light E. 
74.0 
74.0 
69.4 
2 r 00 p . m 
4 
Liffht S- 
74 9 
74 7 
69 8 
2 : 15 p. m 
3 
w. 
75.7 
76.0 
69.4 
2 : 30 p. m 
2 
W. 
75.5 
76.0 
69.5 
2 : 45 p. m 
2 
76.0 
77.0 
70.0 
3 : 00 p. m 
1 
8. E. 
76.6 
77.2 
69 3 
3 : 15 p. m 
2 
8. E. 
76.2 
76.4 
69.8 
3 : 30 p. m 
2 
8. E. 
76.2 
76.0 
69.0 
3 : 45 p. m 
2 
8. K. 
76.0 
76.0 
69.3 
4 : 00 p. m 
1 
8. E. 
76.0 
76.0 
68.8 
4 : 15 p. m 
2 
E. 
75.8 
76.0 
68.2 
4 : 30 p. m 
3 
None 
76.0 
76.2 
69.0 
4 : 45 p, ra 
5 
N. 
75.6 
76.7 
68.7 
5 : 00 p. m 
75.5 
76.8 
68.6 
The temperature of the surrounding lake was taken to detect 
whether the tank caused any material change in the temperature of 
the water in the tank. The difference is slight, and in that respect, 
the small tanks seem to affect the temperature less than larger tanks. 
The water in the tank was sometimes warmer than the surrounding 
lake, occasionally as much as 3° to 5°, but usually less than 1°. The 
consequence of this increase in temperature is to increase the evap- 
oration, and therefore the amounts measured may be considered 
slightly greater than evaporation from the lake itself. 
