The: Fixation oe Nitrogen. 19 
not drained so well as this land, lying as it does on the river bank, 
the most remote part of it being scarcely more than three hundred 
feet from the river, and twelve or fifteen feet above its bed. The 
trees that had died in 1908 were replaced in the spring of 1909. 
On May 6, I have noted that the brown area appears in good con¬ 
dition but that the trees are not doing well. November 2, same 
year, I visited this place again and noted that the apple trees in this 
bad spot had died. The ground had been recently disced and 
seemed in good condition, but those spots which had escaped being 
stirred were brown and mealy. Some one attempted to conduct a 
truck garden immediately north of and contiguous to this ground, 
beginning in 1907. At this time, November, 1909, it was almost 
black in color, encrusted a little and mealy underneath. 
In July, 1910, the condition of the land was worse than I had 
ever seen it, not only the trees but also corn and peas showing the 
effects of the nitre. 
One sample of soil was sent to me in February, 1908, pre¬ 
sumably taken to a depth of from eight to twelve inches according 
to directions. This sample yielded 1.262 percent of salts soluble in 
water, containing nitric acid equivalent to 11.230 percent of the 
soluble salts or 0.142 percent of the air-dried soil, or 5,680 pounds, 
nearly three tons per acre-foot. Other samples of soil were col¬ 
lected at this place at subsequent times, April 21, 1908, April 6, 
1909 and November 2, 1909. ,, 
Further back from the river we have seepage beyond a ques¬ 
tion. We found the water table at from two to eleven feet, but the 
water at the latter depth was under considerable hydrostatic pres¬ 
sure and rose in the holes dug to within two and a half feet of the 
surface. The party who procured some of the water samples for 
me described this fact as follows: “It kept getting wetter until [ 
struck gravel, at four feet, when the water rushed in and bubbled 
up as if under pressure. The water rose sixteen inches in thirty 
minutes, and finally stood at two and one half feet below the 
surface.” The gravel here referred to is very probably the natural 
drainage into the river and this water passes beneath the land which 
we have just described. 
These general conditions are given only because they con¬ 
tribute to a better understanding of the question. I have been 
repeatedly asked whether the seepage water does not bring these 
nitrates into these localities. This question has been raised by the 
character of the samples of drain and ground waters whose analyses 
are given in Bulletin 155, p- 27 et seq. I stated in connection with 
them that the presence of nitrates in the seepage water issuing 
from the shales, for instance, was easily accounted for by the cultiva¬ 
tion of the higher lying mesas, on which these nitre spots occur and 
in some cases are even prevalent. If the seepage water from any 
