582 
BUIvLETIN OF THE BUREAU OF FISHERIES. 
belonging to this class may have a large excess of oxygen in the thermocline; as much 
as 20.0 cc. per liter or more have been found in some of the small lakes of Wisconsin. 
In lakes of the second class there may be either an appreciable decrease of oxygen 
in the thermocline, as in Green Lake, Wis., or the amount may be larger than that 
found in the epilimnion or the hypolimnion, as in Canadice and Hemlock Lakes. The 
oxygen curves of the latter lakes (fig. ii and 12) show that the maximum amount of 
Fig. II. — Dissolved gases, Canadice Lake, Aug. 24, 1910. 
For explanation, see fig. 9, p. 580. 
rr 
X 
■ 
T 
1 
1 
1 
1 
1 
L_ 
1 
1 
1 
A 
\ 
1 
1 
1 
1 
1 
1 
1 
1 
1 
1 
1 
j 
\ 
9 
1 
\ 
\ 
¥ 
1 
i 
9 
1 
1 
1 
V 
L_ 
F 
/ 
/ 
V 
1 
4 - 
/ 
/ 
\ 
/ 
ii 
1 
\ 
f 
1 
1 
1 
\ 
1 
A 
1 
\ 
r 
/ 
1 
1 
\ 
1 
1 
1 
M 
4 
L 
T 
/ 
A- 
1 
1 
/ 
X 
1 
1 
1 
\ 
1 
1 
I 
1 
\ 
4 
1 
1 
1 
N 
0 
& 
6 
Fig. 12. — Dissolved gases, Hemlock Lake, Aug. 23, 1910. 
For explanation see fig. 9, p. 580. 
this gas was obtained in the thermocline, a small excess being present there. This 
increased quantity doubtless represented oxygen that had been liberated in this stratum 
by chlorophyllaceous organisms. 
In the third class of lakes there was a larger quantity of oxygen in the thermocline 
than in the epilimnion, owing to the fact that this water was cooler, hence capable of 
holding a larger amount in solution. (See fig. 13-18.) 
