374 
BULLETIN OF THE BUREAU OF FISHERIES. 
Table 13. — Differences in surface and bottom temperatures observed in Lakes Keokuk and Pepin, July and 
August, 1921. 
LAKE KEOKUK. 
Station. 
Date. 
Time. 
Depth. 
Differ- 
ence in 
temper- 
ature. 
16 
July 20 
...do 
2-3 p. m 
Meters. 
2. 7 
°C. 
0.2 
17 
3-4 p.m 
5.2 
18 
July 21 
8-9 a. m 
3.0 
1.0 
19 
...do.. .. 
10-11 a. m 
4.3 
.7 
22 
July 22 
3-4 p.m 
6.1 
3.0 
23 
July 23 
9-10 a. m 
1.5 
.1 
24 *... 
...do 
10-11 a. m 
3.0 
25 , 
...do.. .. 
11-12 a. m 
6.1 
.5 
July 25 
10-11 a. m 
6.1 
.8 
...do.... 
11-12 a. m 
6.7 
1.8 
28.. . 
. .do. . . . 
2-4 p.m 
4.6 
3. 5 
July 26 
. . .do. . . . 
9-10 a. in 
4. 3 
’ 8 
30.. . . 
10-11 a. m 
6. 1 
.7 
31 
12 noon -1 p. m 
6. 1 
1*7 
32 
July 28 
. . .do. . . . 
9-10 a. m 
3.0 
. 7 
33.. . . 
10.30-11.30 a. m 
7.6 
34 
...do. . . . 
12 noon -1 p. m 
7.6 
1.6 
36 
July 29 
10-11 a. m 
7.6 i 
1.9 
37 
11.30 a. m.-l p. m 
3-4 p. m... 
6. 1 
1.9 
. . .do. . . . 
6. 1 
.2 
39.. 
.do. . . . 
7.6 
40 
July 30 
..do. . . . 
9.45?io.30a. m 
6. 1 
'.7 
41. . 
10.45-12 a. m 
9. 1 
1 8 
42 
11 a. m.-l. 30 p. m 
9. 1 
2.2 
43.. . . 
...do.. . . 
2-3 p. m 
7.6 
2. 1 
44 
3-4.30 p. m 
13.4 
3.5 
LAKE PEPIN. 
58 
Aug. 18 
3.30-4.30 p.m 
9.1 
3.6 
59 
Aug. 22 
9-1). a. m 
7.6 
4.0 
60 
...do 
11-12 a.m 
6.1 
1.1 
63 
...do 
3-4 p. m 
6.1 
.3 
64 
...do 
4.30-5.40 p.m 
9.1 
.7 
65 
Aug. 23 
...do 
9.45-10.30 a. m 
4.6 
.3 
66 
10.30-11.30 a.m 
6.1 
1.1 
67 
...do 
11.45 a. m.-12.40p. m 
10.7 
1.9 
...do.. . . 
1.40-2.45 p. m 
13.0 
1.4 
69”"!!""!""!!"””"!!!”””!”””"! 
...do 
2.50-3.10 p. m 
1.2 
2.0 
70 
...do.... 
3.15-4. p. m 
.6 
1.2 
72 
Aug. 24 
10-11 a.m 
7.0 
1.3 
73 
...do 
11-12 a.m 
5.5 
3.2 
74 
...do 
1.10-1.40 p. m 
4.0 
3.8 
75 
...do 
1.50-2.30 p.m 
7.6 
4.8 
76 
...do 
2.40-3.20 p. m 
9. 1 
6.5 
78 
Aug. 25 
11-11.30 a. m 
7.3 
79 
11.45 a. m.-12.10 p.m 
5.5 
2 !? 
80.. 
do. . . . 
12.15-12 .45 p.m 
.9 
.5 
81 
1.50-2.25 p.m 
6. 1 
2.3 
82 
2.40-3 p. m 
4.6 
2.3 
83.. 
...do.. . . 
3.15-3.45 p. m 
2.7 
1.5 
84 
Aug. 26 
...do. . . . 
12.30-1.15 p. m 
5.2 
.7 
85.. . 
1.30-2 p. m 
3-4 p. m 
4.3 
1.5 
86 
...do 
3.0 
2.6 
87 
Aug. 27 
do 
11.30 a. m.-12 noon 
3.1 
12 noon- 12.30 p. m 
l! 5 
.4 
89 
. ..do.. . . 
1-1.30 p. m 
1.5 
2.9 
90.. 
..do 
1.40-2.30 p.m 
3.6 
4.4 
117 
Aug. 29 
...do.. . . 
9.30-10.45 a.m 
7.6 
.4 
119... 
4-4.30 p. m 
6.1 
2.0 
