22 
Bulletin 65. 
tainly extends too far, that is, we can not say how long it would 
take to effect the same amount of change by the soil agents, as is 
effected by an acid solution and heat during the five days digestion, 
or by strong acid in ten hours. 
THE SAMPLES ANALYZED. 
§ 44. The samples and the manner in which they were taken 
have already been described. Two sets of samples were taken, one 
on May 13, and another on October 20, 1897. These samples were 
taken from the same parts of the plot, in order to make them agree 
as nearly as we could. We hoped that the earlier samples would 
enable us to ascertain the composition of the soil, the later ones to 
determine, if possible, the effects of cultivating, irrigating, and crop¬ 
ping it. The crop grown was sugar beets. The work done on the 
crop, both in the field and laboratory, is recorded in Bulletin 46. 
The whole crop, both roots and tops, had been removed before we 
took the samples in October. 
WATER RECEIVED. 
§ 45. The rainfall was about 9 inches. The amount of irriga¬ 
tion water used in the two irrigations given was not measured, but 
w 7 as estimated by an experienced man to be about 8 inches, or 
approximately 17 inches in all. The drainage of this plot of ground 
is not good, and we now know that it receives water from the west 
as sub-irrigation. This we did not know at the beginning of our 
experiment, or rather we supposed that we were protected from this 
interference by a ditch and a drain. The water plane during this 
season was higher than during the succeeding season of 1898, but 
this, I think, was due in part to greater rainfall and more frequent 
irrigation. Two factors enter here which are wholly undetermined, 
the upward movement of the water-soluble salts in the soil, due to 
evaporation from the surface, and the salts removed by drainage. 
The former was made as low as our conditions would permit, by 
keeping the surface soil well stirred by frequent cultivations, and by 
the luxuriant growth made by the beet tops. I do not know how 
much either of these agencies accomplished during the season, nor 
do I know that any attempt has been made to determine the 
amount of evaporation from the surface of the soil at this place 
under any conditions. The amount of drainage from this plot was 
sufficient to lower the water table, after it had been raised by irri¬ 
gating the plot, two feet in eleven days. In this case, the adjoining 
land had received no irrigation, and the rise in the water plane was 
purely.local. 
§ 46. The draining out of the water may have been due as 
much to a spreading of the water over a larger area, as to draining 
out. Under such conditions as the early summer season presented, 
