188 -Wisconsin Academy of Sciences, Arts, and Letters. 
Fig. 2.—Diagram to show the heat income of Cayuga lake. The date of the 
winter temperature was Feb. 13, 1911; those of the summer temperatures were 
Aug. 11-12, 1910 (full line) and Sept. 2, 1911 (dotted line). 
warmer, and at 100 m. and below the lakes were of the same 
temperature. The heat budget of the lakes differs widely, being 
about 44% greater (11,400 cal.) in Cayuga lake than in Wiirm- 
See. But little of this difference comes in the upper 10 m. 
where the greater reduced thickness of Wurm-See compensates 
for its lower temperature. Nearly 70% of the difference comes 
in the strata between 10 m. and 40 m., where the temperature 
of Wurm-See is much below that of Cayuga; and a great part 
of the remainder comes in the bottom strata whose volume is 
much smaller in Wurm-See, corresponding to its smaller max¬ 
imum depth. 
