28 
The Colorado Experiment Station 
On the other hand, a sample of ground-water taken only fifty to 
sixty feet from where this sample was taken, carried only 4.0 p. p. 
m., while the surface three inches of soil contained 422.7 p. p. m. 
of nitric nitrogen. In this case nearly all of the nitric acid was 
within 18 inches of the surface; from the 19th to the 31st inch 
inclusive, the soil contained only 5.0 p. p. m., and from the 43rd 
to the 54th inch it contained only 0.1 p. p. m. and the ground-water 
as stated 4.0 p. p. m. The former ground had been irrigated and 
the latter probably not. 
We regret that we cannot give the results of more extended 
experiments to determine how the movement of the salts in the 
soil is influenced by the capillary movement of water in the same, 
and how the movement of one salt may be influenced by the pres¬ 
ence of other salts. If others have studied these problems their 
work has not come to my knowledge. The work done in connec¬ 
tion with this bulletin was too far advanced when the desirability 
of such a study in this connection became evident to us. We made 
an attempt to carry out three experiments but this is too small a 
number of experiments, and the time at our command was too 
short to arrive at more than tentative results. In these experiments 
we took a fine, sandy to silty loam which we had previously 
analyzed. We re-determined the total nitrogen, nitric nitrogen and 
chlorin. We brought this soil into tubes ij 4 inches in diameter 
and 50 inches long. The tubes were cut into sections, 10 inches 
long, and united by rubber bands. In one case we brought the 
lower end of the soil column just below the surface of distilled 
water contained in an appropriate vessel. The lower end of the 
second tube was brought below the surface of an eight percent 
solution of calcic nitrate and sodic chlorid. In the third tube we 
mixed the calcic nitrate with soil and filled the top three inches 
of the tube with the mixture. This tube caused us trouble and as 
we had to try to manipulate the soil in the tube, finally taking out 
a portion of it and filling up one ten-inch section, there is too great 
a degree of uncertainty attaching to the results to justify us in 
giving them. We will give the other two only, i. e. the soil columns 
in which the distilled water alone or the solution of nitrates and 
chlorids were used and in which the water rose to a height of 
thirty-five inches. 
