Birge—Work of Wind in Warming a Lake. 377 
Plate IV 
Plate IV. Part of Plate V on a larger scale. (See p. 347.) 
A = mean temperature, 19.11°; A'=value 1 —D for mean tempera¬ 
ture, 0.001590; B'=mean value 1 —D, 0.001705; B = temperature 
corresponding to 0.001705, 19.68°. 
