The Fixation oe Nitrogen in Colorado Soils 7 
termined by the salts contained in the soil above the level of the 
water-plane, but represent much more nearly the salts held in the 
soil at this plane. This would of course be modified if there were 
a considerable volume of water moving freely downward through 
the soil, this, however, was not the case, and we found that there 
was an intimate relation between the height of the water-plane and 
the salts held in solution. In other words it was the salts in the 
soil and not those in the ground-water per se that determined the 
quantity and character of these salts in our case. We dug two 
holes at a period when the water was very high and, shutting out 
as best we could, by means of tiles, the water from the higher 
sections, we collected water representing three sections in one hole 
and four in another. 
The results are given 
in p. p. m. 
in the 
following statement: 
Total solids 
Chlorin 
Nitric 
Nitrogen 
Unio l\Tn 1 1 «t Spr> 
. 2,842.8 
232.9 
1.28 
9.nrl Spp 
. 2,450.0 
177.9 
0.76 
3rd Sec. 
. 1,938.5 
117.9 
0.36 
Unlo TSTn 0 let Spp 
. 3,395.7 
213.6 
1.76 
. 2,848.5 
146.4 
1.00 
. 3,092.8 
149.3 
1.76 
4th Sec. 
. 2,985.7 
156.4 
1.68 
The total solids in the water obtained from the first hole de¬ 
creased rapidly with depth, but this decrease was not so marked in 
the second hole. The chlorin in the top sections of these holes is 
comparatively high and falls abruptly in the second section. The 
nitric nitrogen in these waters is very moderate in quantity, and in 
the first hole falls rapidly with depth, but the second section of the 
second hole alone shows any considerable variation. The ratio of 
nitric nitrog'en to the chlorin in these cases is altogether enatic and 
bears no definite relation to the total solids or to the chlorin, even 
if the nitric nitrogen were present in quantities to be of any sig¬ 
nificance, which it is not. This relation between the depth of the 
water-plane and the total solids held in solution, was shown, too, 
in the variations in the waters of the permanent wells which we 
observed for more than three years. Each well had its own peculiai- 
ities, even when they were located close to each other. The follow¬ 
ing may illustrate this point. We will designate the wells as i, 2 
and 3. 
Wells numbered 1 and 2 were close together, in fact were 
less than twelve feet apart, while number 3 was not more than 150 
feet away. The results in the case of well number 3 are. scarcely 
more striking than those obtained with the aii-diied soil, 
but they are easily explained. When the water in the well 
was low, the salts in solution were also low, as the water- 
