224 
IOWA ACADEMY OF SCIENCES 
1894-1898, obtaining a chart which presumably is characteristic for the 
cyclonic conditions on the southwest plains. I also combined into like 
averages the same observations at Helena, Miles City, Leander and Boise 
City, for 1899; those taken at nine stations in the Upper Mississippi Val- 
ley in 1899; and those taken at Detroit and at Buffalo during the years 
1900-1908. 
The percentages of precipitation in the twenty-four cyclonic tracts for 
each of the five localities thus averaged are given in the following table, 
and the same data are plotted in the accompanying figures (Figs. 2-6). 
TABLE. 
Showing percentages of precipitation in twenty-four different tracts 
of five composite cyclones in different parts of the United States. 
Number of Tract. 
Davenport. 
i Amarillo, Dodge 
City, Wichita and 
Oklahoma. 
1 Helena, Miles City, 
Leander, and 
Boise City. 
Missouri Valley | 
Stations. 
Detroit and Buffalo 
1 
26 
3 
0 
20 
44 
2 
21 
14 
17 
21 
40 
3 
15 
20 
10 
11 
40 1 
4 
0 
- 
6 
8 
40 
5 
3 
5 
0 
5 
26 
6 
4 
3 
3 
5 
15 
7 
7 
9 
3 
7 
15 
8 
35 
5 
13 
11 
26 
9 
17 
21 
16 
15 
33 
1 
17 
21 
18 
20 
25 
11 
8 
19 
6 
20 
18 
12 
1 
8 
13 
14 
6 
17 
13 
2 
10 
2 
18 
14 
4 
2 
6 
5 
6 
1 
4 
8 
4 
2 
0 
1 16 
10 
6 
5 
6 
34 
ITT 
0 
21 
20 
6 
25 
18 
17 
18 
8 
9 
' 19 
19 
6 
12 
9 
8 
2 
6 
8 
8 
9 
1 21 
2 
6 
5 
2 
6 
22 
22 
6 
2 
3 
- 
23 
7 
7 
2 
4 
0 
24 
6 
7 
3 
4 
1 
25 
0 
6 
16 
3 
0 
