Pietenpol—Visible Spectrum of Wisconsin Lake Waters 577 
TABLE 4 
EFFECT OF DEPTH ON OOEFFIOIENT OF ABSORPTION 
Lake Mendota, July 15, 1915 
Wave length 
Surface 
20 meter 
Wave length 
Surface 
20 meter 
4700 
.259 
.274 
5895 
.239- 
.254 
4940 
.186 
.172 
6005 
.243 
.278 
5220 
.146 
.154 
6180 
.294 
.321 
5S90 
.141 
.167 
6360 
.356 
.864 
5S80 
.153 
.173 
6480 
.374 
.369 
5790 
.199 
.217 
6630 
.376 
.372 
4500 5000 5500 6000 6500 
Fig. 6. Absorption curves for water from Turtle lake, to show the effect on 
time in decolorizing water kept in the dark, 1. Dec, 4, 1915 ; 2. Oct, 
18, 1915 ; 3. Sept. 17, 1915. Sample was taken Sept. 3, 1915. 
8. General Table op Results 
The lakes in the following table may be found listed in 
Juday’s report on the Hydrography and Morphometry of Wis¬ 
consin lakes (Bull. Wis. Geol. & Nat. Hist. Survey, No. XXVII, 
1914.) Table 1, p. 122, and Table 3, p. 125, contain the hydro- 
graphic data for all of them. 
37—S. A. L. 
