SALMON INVESTIGATIONS IN IDAHO IN 1895. 
163 
parts was found to be from 4° to 10° colder during the day than the surface tempera- 
ture taken at the same time. The maximum difference was found at noon. July 20, 
when the surface was 08° and the bottom, at 105 feet, 58°. This is probably as great 
a difference as existed at any time, even in the warmest weather. The nights were 
always quite cold enough to reduce the temperature of the surface water to that of 
the bottom or even below it, and not until some time after sunrise would it again 
exceed the bottom temperature. 
Teviperatures taken in Pettit Lake and connecting streams in July and August, 1S95. 
Date. 
South inlet. 
North inlet. 
Lake. 
Outlet. 
Surface. 
Bottom. 
Air. 
July 26 
29 
53°, 12.30 p.m. 
52°, 11 a. m 
50°, 10 a.m.... 
63°, 1 p.m 
48J°, 11 a. m. - . 
30 
65°, 9.30 a.m.. 
60°, at 70 feet, 9.30 a. m. . 
Aug. 1 
2 
17^0, 9.30 a. m. 
6 
48°, 10.30 a. m. 
51°, 10.15 a. m. 
8 
9 
86° Sam 
11 
46°, 11.45 a. m. 
49°, 10.45 a. m . 
50°, 12.15 p.m. 
80°, 5.17 p. ra. . 
13 
49°, 10.45 a.m. 
14 
61°, 9. 15 a. m. 
17 
71°, 3.50 p.m. 
07°, 2 30 p.m. 
22 
23 
47°, 10 a.m 
25 
47°, 8.45 a.m .. 
44°, 10.10 a.m. 
47i°, 8.45 a.m. 
48°, 10.30 a.m. 
61°, 6.15 p! m. 
20 
62°, 11.15 a.m. 
63^°, 11.30 a. m. 
27 
45°, 12.30 p. ra . 
47°, 11.30 a.m. 
57°, 10 a. m, 
‘ Temperatures recorded in this paper are in Fahrenheit degrees and taken with the Wilder protected tliermometer. 
Temperatures taken at camp on Pettit Lake, August 12 to 28, 1895. 
Date, 
8 a 
m. 
12 
m. 
8p 
m. 
Kemarks. 
Air. 
Water. 
Air. 
W ater. 
Air. 
‘Water. 
Degrees. 
Degrees. 
Degrees. 
Degrees. 
Degrees. 
Degrees. 
P 
Aug. 12 
50 
61 
65 
13 
54 
72 
65 
65 
14 
46 
61 
78 
664 
07 
66 
taken at 8 a. m., noon, ami 8 p. m. 
15 
53 
614 
74 
654 
06 
66 
Tlie place selected for taking that 
16 
48 
61 
674 
65 
59 
65 
of the vyater was near our camp, 
17 
48 
61 
71 
04 
63 
654 
which is indicated on tlie map, and 
18 
48 
62 
72 
65 
62 
65 
in water 1 to 2 leet deep, the tlier- 
19 
51 
61i 
76 
66 
64 
66 
mometer being allowed to rest upon 
20 
50 
61 
73 
65 
52 
65 
the bottom. The thermometer for 
21 
51 
63 
04 
63 
58 
64 
air temperature was kept on the 
22 
48 
01 
66 
64 
59 
64 
shaded side of a small cabiu on 
23 
48 
60 
65 
644 
the lake shore at our camp. 
24 
67 
65 
55 
63 
25 
SO 
60 
67 
64 
54 
64 
26 
46 
61 
62 
63 
53 
614 
27 
44 
59 
54 
61 
47 
61 
28 
42 
59 
