26 Tjiic Colorado Experiment Station 
tained a small amount of water at about five and one-half or six 
feet, but there was much less water below this until he reached a 
depth of sixteen feet, at which depth he found water which was 
under some hydrostatic pressure. It rose to about five and one- 
half feet. The water found at about five feet, and that which had 
accumulated in the cellar under the house, was evidently surface- 
water which had accumulated at these depths. The surface-water 
was rich in nitrates, but this water that came from the greater 
depth contained none, though it was very heavily charged with 
alkalis; the total solids amounted to 22,104. P- P- ni - This water 
which had percolated through the shales and formed the ground- 
water at this place, though heavily charged with the ordinary 
alkalis of the section, which were in no way abnormal in their 
composition, contained no nitrates and could not have been the 
source of the nitrates found in the surface-soil. O11 the other hand, 
the water that had percolated from the surface and was met with a 
depth of between five and six feet, was quite rich in nitrates. 
These nitrates had not been collected by the underground-waters 
at some distant locality and brought by them to this place and de¬ 
posited here by their evaporation from the surface of the soil. This 
was not a newly irrigated district. These under-ground waters had 
been there for many years and the orchard had grown healthily for 
thirteen years. The land was alkalized but not worse than the land 
presented as the first case given in this bulletin. As the ground- 
water proper contained no nitrates, though heavily charged with 
alkalis, it was undoubtedly the source of the latter present in the 
soil, but could not be the source of the former. The nitrates found 
in the water met with at a depth of between five and six feet had 
been washed down from the surface and had not been brought up 
from below, that is they had not been gathered from the rocks of 
the country nor from other lands affected with this trouble. 
There is a practical and suggestive question in this connection 
which has been raised by intelligent orchardists, i. e. is there danger 
of spreading the trouble by the inoculation of one soil from another, 
and by the use of drainage water for irrigation, and further, is 
there any danger of injury from the use of such water due to the 
presence of nitrates already formed? I do not believe that there is 
danger from the latter source, at least, not in general. 
THE FOURTH PLACE CHOSEN. 
The fourth place selected was a section of country on a mesa 
where a few years ago no “brown spots” were recognizable, but 
where they have made their appearance since our earlier observa¬ 
tions of this section. The inconveniences and mishaps in collecting 
