|SEEPAGE OR RETURN WATERS FROM IRRIGATION. 43 
thermometers: One in well-drained irrigated soil; one in low, 
undrained irrigated soil, the water standing within six feet of the 
surface; and one in well-drained unirrigated soil. At a depth of 
six feet the variation during the year is from 20° to 24°, being 
least in the low T ground. At three feet in depth the range is 32°. 
At six feet the highest temperature of the year is reached early in 
•September, the lowest early in March. Its temperature thus lags 
six or eight weeks behind the temperature of the surface. At 
three inches depth the annual range is about 70°. With the range 
of temperature at the depth of six feet, other conditions remaining 
the same, one-third more water would flow in August than in March, 
and at a depth of three feet, nearly one-half more. 
But as the gagings of the different years were made at almost 
the same time, the difference in temperature is comparatively small, 
and the effect in different years for the same month will be less 
marked. Nevertheless it is not insignificant. 
The table shows the average temperature at three and six feet 
depth during the time of the gagings of the Poudre river, and the 
amount of inflow found is shown in the fourth column. 
Had the temperature been uniformly 60° instead of that 
observed, the amount of seepage would have been that given in the 
last column. This is under the supposition that the temperatures 
at three and six feet in depth from the surface will be the most influ¬ 
ential. The correction is obtained by determining graphically the 
co-efticients of viscosity from the co-efflcients, at 32°, 50°, 68°, etc.f 
TABLE VIII. 
TEMPERATURE OF SOIL AT 3 AND 6 FEET BELOW SURFACE, 
AND ITS EFFECT ON SEEPAGE. 
Year. 
Th rmometers. 
Set A. 
Thermometers. 
Sat B. 
Am’t of Seep¬ 
age in Poudre 
River. 
Am’t Corrected 
for Tempera¬ 
ture of 60°. 
Oct 1839 
57 8 
59.4 
99.0 
101 
Set A in dry, well drained irrigated soil. 
Oct., 1890. 
58.7 
56.2 
100.8 
104.8 
Set B in low ground, water standing within six 
Oct.,' 1891. 
55.7 
54.9 
84.6 
90.4 
feet of the surface. 
Mar., 1892. 
38.9 
40.0 
*96. 
122.0 
Oct., 1892. 
60.4 
59.9 
101.6 
101.4 
Nov., 1893. 
51.5 
53.4 
98.7 
108.6 
Mar., 1891. 
36.2 
37,9 
82.3 
107.2 
Aug., 1894. 
64.3 
62.5 
118.2 
113.5 
Oct., 1895. 
52.2 
52.3 
164.4 
187.4 
* To Ogilvy ditch. 
The amount of return throughout the year is sensibly the same, 
the principal disagreement being the one for March, 1892, when 
the gain in less than the full distance would have been 122 second- 
| Daniell’s Physics, p. 306. 
