CEREAL EXPERIMENTS AT JUDITH BASIN SUBSTATION. 7 
given for the seven years from 1909 to 1915, inclusive. This table 
also gives the total and average precipitation and evaporation in this 
period, with the ratio of the total precipitation to total evaporation. 
Table VI. — Monthly 'precipitation and evaporation {in inches) from a free water surface 
at the Judith Basin substation, Moccasin, Mont., from April to September of each year 
from 1909 to 1915, inclusive. 
[Data from the records of the Biophysical Laboratory of the Bureau of Plant Industry..] 
April. 
May. 
June. 
July. 
August. 
September. 
Total. 
Year. 
Pre- 
cipi- 
ta- 
tion. 
Evap- 
ora- 
tion. 
Pre- 
cipi- 
ta- 
tion. 
Evap- 
ora- 
tion. 
Pre- 
cipi- 
ta- 
tion. 
Evap- 
ora- 
tion. 
Pre- 
cipi- 
ta- 
tion. 
Evap- 
ora- 
tion. 
Pre- 
cipi- 
ta- 
tion. 
Evap- 
ora- 
tion. 
Pre- 
cipi- 
ta- 
tion. 
Evap- 
ora- 
tion. 
Pre- 
cipi- 
ta- 
tion. 
Evap- 
ora- 
tion. 
Ratio. 
1909.... 
1910 
1911 
1912 
1913 
1914 
1915.... 
1.03 
1.31 
1.66 
1.43 
.79 
1.19 
1.43 
3.00 
5.18 
4. 10 
2.62 
3.89 
3.21 
4.70 
1.34 
2. 40 
2.98 
3.94 
2. 64 
2.91 
2. 12 
4.66 
5.61 
5.94 
4.14 
4.23 
4.85 
4.61 
5.99 
2^55 
.64 
4.77 
4.64 
3.97 
6.00 
7.21 
5. 13 
6.39 
4.90 
4.43 
4.35 
2.54 
1.10 
.50 
1.92 
1.12 
.64 
3.54 
7.22 
8. 28 
7.31 
5.97 
6.37 
7.45 
4.89 
4.21 
2.02 
6.34 
1.27 
.51 
.65 
.92 
7.06 
7.38 
6.35 
6.23 
7.35 
7.24 
6.51 
4.47 
2. 54 
1.37 
1.63 
1.01 
1.11 
2. 65 
4.67 
6. 48 
3.41 
3.42 
5.83 
5. 10 
3.43 
19.58 
11.06 
15.40 
10.83 
10. 84 
11.14 
14.63 
32.61 
40. 14 
32.22 
28. 77 
32.58 
32.27 
28. 49 
1 
1 
1 
1 
1 
1 
1 
1.6 
3.6 
2.1 
2.6 
3.0 
2.8 
1.9 
Average 
1.28 
3. 81 
2. 92 
4. 86 
3.04 
5.49 
1.82 
6.78 
2. 27 
6. 87 
2. 11 
4.62 
13.35 
32. 44 
1 
2.4 
The greatest evaporation in any one year, as shown in Table VI, 
was 40.14 inches (1910). While the seasonal precipitation (Apr. 1 
to Sept. 30) in 1910 was not quite as low as in some of the other 
Fig. 2. — Map of Montana, showing the average annual precipitation (in inches) at the Judith Basin sub- 
station and at 24 other points in the State. These averages, for the most part, are for 16 years (189S to 
1915, inclusive). 
years, the ratio between the precipitation and evaporation was 
wider than in any other year. The average ratio for the seven years 
is 1:2.4. A comparison of this ratio with the ratios for the different 
years gives a very fair basis for judging the seasonal conditions under 
which the experiments for each year were conducted. 
48601°— Bull. 398—16 2 
