bulletin 82. 
44 
very rapid at first and gradually becomes slower which fully ex¬ 
plains the differences observed in these two sets of samples. It is 
evident from what I have said, relative to the amount of off-flow 
and the fact that it was only by the courtesy of the water com¬ 
missioner that we obtained this water, that we did all that we 
could with this subject. When we consider that this water 
on leaving the plot after flowing over it for 600 feet had 
only washed off and dissolved out between 800 and 1,000 pounds 
of salts per acre-foot, under very favorable conditions, and that the 
rate of action decreases rapidly it would seem to indicate that long 
continued flooding with off-flow would not be an advisable pro- 
ceedure in order to remove salts from the soil. 
§ 74. There is one thing suggested by the analyses, i. e., 
that in the case of long continued flooding the amount of potash 
removed might become a matter worthy of consideration. The 
percentage of this substance present in the residue from the off- 
flowing waters is not so high as in the residue obtained from the 
waters applied, but when the increase in the total solids is taken 
into consideration it indicates a probable loss of this substance. 
Our data is not adequate to justify general conclusions on this 
subject. My opinion, however, is that the loss is less serious than 
one would be inclined to think, judging from the results shown by 
these samples. 
§ 75. The sanitary analyses show the same facts relative to 
the total solids and chlorin, but they are given in terms of parts 
per million, instead of grains per gallon. In the total solids we 
discover an extreme quantity in the well waters after irrigation, 
equal to 13 times the quantity in the water used for irrigating, and 
over four times the amount found in the same well before irriga¬ 
tion. The chlorin is 40 times greater in the well water after irri¬ 
gation than in the ditch water applied, and between six and seven 
times greater than in the same well before irrigation. The principal 
object in making the sanitary analyses was to determine the dif¬ 
ferent forms and quantities in which nitrogen was present. The 
quantities found, even when taken together, are scarcely worth 
considering so far as their fertilizing value is concerned. The 
ditch water used in 1899 contained in all forms almost three 
pounds of nitrogen per acre-foot. The soil to which this water 
was applied contained in the first foot of soil 3,500 pounds. The 
three pounds of nitrogen, if it were present as potassic nitrate, 
would be insignificant, but the analysis shows that none of it was 
present as nitric acid. This ditch water shows the presence of 
more nitrous acid than any sample analyzed in connection with 
the work. 
§ 76. The seepage water that mingled with the ditch water 
was even poorer in nitrogen than the ditch water, so the water 
