32 
Colorado Experiment Station 
would add somewliat to the value of the data. In the last table 
I'oi* instance, the 22-foot well of P. Aragon is in a depression in 
otherwdse high ground and is remote from his building, in fact 
it is in a field. The total solids are very high, 10,722.0 p.p.m., 
with only 0.5 p.p.m. of nitric nitrogen, whereas the shallow 
well on the Ruff place is similarly located, i.e., on the edge of a 
depression in high land, really on a hillside, carries 7,462.0 
p.p.m. of total solids and 131.6 p.p.m. of nitric nitrogen. These 
wells may be 7 miles apart on a straight line. Again the well 
on M. J. Kerr’s place was given as 12 feet deep, but when the 
sample of water was taken, the well was full to the top. This 
water was being used for irrigating other land. It was evi- 
dently seepage water from the immediate vicinity of the well 
and contained 4,340.0 p.p.m. total solids and 28.0 p.p.m. nitric 
nitrogen. On the Seth Lewis place a pumping plant had been 
established for using the seepage water in irrigating adjacent 
•land. The plant raised the water from a depth of 10 feet. The 
water carried 1,784.0 p.p.m. of total solids and only 0.6 p.p.m. 
nitric nitrogen. It is evident that there is no general subsurface 
source from which these nitrates are obtained. 
KITRIO NITROGEN IN THE SURFACE SOILS 
One of our principal objects in this work was to find out 
whether there was any relation between the quantities of nitric 
nitrogen in the soils and in the well-waters. This subject has 
been suggested but not dwelt upon in other bulletins. In Bulle- 
tin 186, p. 38, it is stated that the soil there discussed carried 
in the top 3 inches, 42.3 p.p.m. nitric nitrogen, which decreased 
rapidly till at 4 feet 9 inches it contained less than 1.0 p.p.m. ; 
the ground- water at this point carried 9788.0 p.p.m., total solids 
and 4.0 p.p.m. nitric nitrogen. On the page just cited, we find 
another instance given in which the surface 3 inches of soil 
carried 52.9 p.p.m. nitiuc nitrogen and the last section of soil 
taken above the water-plane carried 57.0 p.p.m. of nitric nitro- 
gen. The ground-water out of this hole carried 18,557.0 p.p m. 
total solids and 318.8 p.p.m. nitric nitrogen. The question is 
put. Why this difference in the distribution of the nitrates, and 
the answer given is that in one case the nitrates had been washed 
down into the ground-waters by a previous irrigation, and in 
the other case they were not washed down, because of the un- 
even distribution of the water. Again, one of tlie conclusions 
formulated in Bulletin 178, p. 95, is, ^‘The ground -waters, un- 
less derived from nitre-areas, are free from nitrates and these 
nitrates (in the soil) cannot be accounted for by the evapora- 
