142 
IOWA ACADEMY OF SCIENCE Voi. XXVII, 1920 
open. Furthermore, the rate of evaporation for each individual 
day shows the same ascendency as the above averages. This 
comparison is shown diagramatically in figure 28. 
TABLE B. EVAPORATION IN C. C. AT THE TOP AND MIDDLE 
OF SLOPE FOR TIMBERED, BRUSHY AND OPEN SITES 
Location — Top op Sropp 
Location — Middle op Slope 
Timbered 
Brushy 
Open 
Timbered 
Brushy 
Open 
Date 
Slope 
Slope 
Slope 
Slope 
Slope 
Slope 
(Sta. II) 
(Sta. V) 
(Sta.X) 
(Sta. 1a) 
(Sta. IV) 
(Sta. XI) 
July 13 
4.32 
6.48 
8.50 
2.88 
4.32 
15 
10.80 
14.40 
17.64 
5.76 
8.64 
17 
13.68 
15.12 
17.68 
9.36 
11.52 
19 
13.32 
13.24 
15.64 
6.94 
13.68 
21 
10.80 
14.76 
20.40 
5.40 
12.24 
23 
18.00 
28.08 
34.68 
14.40 
19.44 
25 
18.72 
24.48 
33.12 
12.96 
20.16 
27 
15.84 
25.92 
27.88 
12.24 
21.60 
30.24 
31 
5.04 
5.76 
9.52 
2.16 
5.04 
7.20 
Aug. 2 
14.40 
14.40 
25.84 
9.36 
14.40 
23.04 
8 
7.92 
' 10.08 
14.96 
5.04 
10.80 
12.24 
10 
11.88 
13.68 
19.38 
7.92 
12.96 
18.00 
12 
10.80 
10.80 
19.72 
7.20 
8.64 
18.00 
14 
8.64 
15.12 
18.00 
3.96 
9.52 
18.00 
16 
10.08 
19.08 
25.84 
6.48 
14.40 
23.76 
19 
10.80 
17.64 
20.06 
6.84 
14.40 
19.44 
21 
9.72 
17.28 
24.48 
5.04 
12.96 
20.16 
23 
7.20 
12.24 
14.28 
4.68 
9.36 
15.12 
25 
13.32 
19.44 
26.86 
7.92 
18.00 
21.60 
27 
11.16 
18.72 
23.12 
7.92 
15.48 
20.52 
29 
7.92 
17.00 
5.04 
14.40 
31 
12.96 
23.80 
7.20 
18.72 
Total 
247.32 
316.12 
425.38 
157.70 
257.56 
280.44 
Aver, for 
season 
11.24 
15.83 
20.25 
7.12 
12.87 
18.69 
The results obtained here agree closely with data presented by 
Fuller ® as the result of comprehensive studies carried on for 
three seasons in the sand dune region near Lake Michigan. He 
showed that in this region there exists a direct relation between the 
rate of evaporation and the succession from pioneer cottonwood 
to climax beech-maple associations. The average daily evapora- 
tion rates for the three seasons in this region were found by Ful- 
ler to be as follows : Cottonwood dune, 22.3 c.c. ; edaphic prairie, 
12.5 c.c. ; Oak dune, 11.0 c.c.; Pine dune, 10.4 c.c.; Oak-hickory 
forest, 8.8 c.c. ; beech maple forest, 7.0 c.c. Transeau in con- 
nection with studies made near Cold Springs Harbor, Long Island, 
New York, has presented similar facts. Likewise, Weaver 
9 Fuller, G. D., Fvaporation and soil moisture in relation to the succession of 
plant associations: Bot. Gaz. 58 , 19'3-234, 1914. 
10 Transeau, E. N., The relation of 'plant societies to evaporation: Bot. Gaz. 54 , 
424-426, 1912. 
