6 
Bulletin 72. 
condition would have done, causing the plants to suffer. The plant, 
too, may have become more sensitive to a lack of water, owing to 
the usually large supply of it. Whether this is the explanation 
or not, we had to irrigate two out of three seasons, and while we 
irrigated the third season also, it was probably not actually neces¬ 
sary so far as the growing of the beets was concerned. 
§ 11. The height of the water table in the plot was referred to 
a plane 10 feet below our bench mark. The wells were designated 
as A, B, C, D, E, F, G and H; their respective heights, referred to 
the same plane, were: A, 9.41'; B, 11.12'; C, 11.23'; D, 12.71'; 
E, 7.24'; G, 9.59'. The heights of F and II were not determined; 
these wells were dug for special purposes, which it would be out of 
place to explain at this time. Wells A, B, C and D were the prin¬ 
cipal ones and were dug at intervals along the central line of the 
plot, which had a width of 50 feet and a length of 000 feet. The 
distances between the wells were not equal. Well A was the most 
easterly one, and was 130J feet from the center of the ditch ; B was 
150 feet west of A; C 175~ feet west of B, and D 160 feet west of C. 
The surface of the plot at D is 3.3 feet higher than at A ; the sur¬ 
face of the underground water is 1.83 feet higher. The distance 
from A to D is 485 feet, accordingly the surface of the water table 
has a fall of 1.83 feet in 485 feet, while the surface of the plot has a 
fall of nearly twice as much. The greater height of the water table 
at the west end is probably due to the friction of the flow, and is but 
little modified by the contour of the surface. 
§ 12. I suppose that the escape of the ground water is to the 
eastward, though I have no direct proof of this. There is a drain 
running from a depression west of the plot, making a wide curve 
and passing again to the east of it. This drain was put in in this 
shape to cut off seepage from higher lying land to the westward 
and to drain a still lower lying portion to the east of the plot. I 
have elsewhere stated that it accomplished its purpose but par¬ 
tially. 
§ 13. The daily records of the height of the water plane show 
that it varied quite uniformly throughout the plot—the wells as a 
rule rising and falling together. At times there would be a rise in 
the water table when no rainfall had taken place and no land had 
been irrigated which could affect the height of the water plane in 
this plot. Such rises in the water plane were-probably due to 
meteorological conditions. A rainfall of a fraction of an inch also 
affected it, owing to the nearness of the plane to the surface, by 
modifying the capillary force within the soil. A rainfall of 0.28jof 
an inch at 4:30 on the 8th of July was followed on the 9th by a rise 
of from 0.74 to 0.90 of a foot in the water level; but a rainfall of 
0.9 of an inch on the night of the 9th produced a mixed result, 
