114 
Keport of the Horticulturist of the 
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In the true lysimeter the 
movements of water must 
be the same as in the nat- 
ural soil. As a means of 
approaching this condition, 
an apparatus for which I 
am in part indebted to the 
suggestions of the station 
chemist, Dr. Babcock, has 
been constructed after the 
plan shown in the accom- 
panying drawing. It differs 
from the lysimeter hereto- 
fore used in being provided 
with an artificial water- 
table, which is kept at a 
nearly constant height by 
the addition of sufficient 
water daily to make up the 
loss from evaporation. The 
tube that passes out through the bottom of the lysimeter at A, instead 
of serving as the outlet for drainage, curves upward, forming a supply- 
pipe, water being added at the funnel B. The drainage passes out 
through the drainpipe C D, which is perforated in the part within the 
lysimeter, and of which the lower end enters the bottle E. 
In order to insure an even distribution of the water, a layer of 
pebbles is placed at the bottom of the lysimeter, and this is covered 
with another of clean sand, the latter reaching up far enough to cover 
the drain-pipe. Thus the soil above, while not directly in contact with 
water, rests upon a constantly saturated layer of sand. 
This lysimeter furnishes not only a measure of percolation, but also 
during dry weather, an approximately correct daily record of soil evap- 
oration. The excess of drainage over the quantity of water added 
through the supply-pipe represents the percolation, while the difference 
between the amount added and the drainage equals the evaporation. 
The total evaporation for a given period is the difference between the 
total amount added plus the total rainfall, and the total drainage. 
The conditions within this lysimeter differ from those in the outside 
soil in the height of the water-table being constant. But by providing 
lysimeter s of various depths and by noting the fluctuations in the 
height of the natural water-table, a fair estimate may be formed of the 
movements of water in the natural soil. 
