16 BULLETIN 1221, U. S. DEPARTMENT OF AGRICULTURE. 
others in the uniformity of the moisture content of the bottom third 
of the tube. The average moisture content of the whole tube is 27.67 
ercent. ‘This percentage of moisture is found at the twenty-second 
inch, or nearly six-tenths the height of the tube. The lower half of 
the tube contains 59 per cent of all the moisture in the tube. In the | 
bottom nine inches of the tube the average moisture content is 33.62 
per cent; in the next 9 inches the average moisture content is 31.92 
per cent; in the next 10 inches 26.66 per cent; and in the last 10 
inches, 19.47 per cent. The rapid decline in moisture content is 
found in the top fourth, as shown by the curve, Figure 5. 
DISTRIBUTION OF MOISTURE IN HORIZONTAL SOIL COLUMNS. 
While these tubes are designated as “horizontal,” they all had 
a rise of one-tenth of an inch per foot from the water end to the outer 
end. 
Although the tests made with the horizontal tubes do not give 
sufficient data upon which to base any very definite conclusions, four 
of them are included to indicate what distribution of moisture may be 
expected in soil columns handled as these were handled. 
The four tubes in this set were each manipulated in a different 
way. Differing as they do these four tubes were selected for the 
reason that there were not sufficient tests made by any one method 
to give more conclusive data than could be obtained from a single test. 
It must be kept in mind that all horizontal columns had a vertical 
rise of 4 inches from the water in the tank before a change to the 
horizontal was made. The arbitrary distance was used so that the 
results might be adapted to the work done previously at Riverside. 
In sampling the tubes, the 4 vertical inches and the first hori- 
zontal inch of the tube was discarded. Thus, the first sample, 
designated as the first inch in the table, was the sixth inch from the 
water. | 
Tube No. 17 was filled with Idaho lava ash soil and was packed 
in the same way as tube No.1. This tube stood 21 days and was then 
sampled immediately. 
Tube No. 18 was filled with Riverside decomposed granite soil and 
was packed in the same way as tube No.1. In this tube the moisture 
had reached the outer end of the soil in the tube a few days before 
samples were taken. For a few days evaporation was taking place 
at the outer end of the soil column and in that respect this tube 
differed from all the others. This tube stood 32 days before sampling. 
Tube No. 19 was filled with soil from Cache Valley and was packed 
in the same way as tube No.1. The horizontal joints of this tube were 
not wrapped with friction tape and were open to air circulation. To 
that extent this tube differed from all the others. It stood 26 days 
before sampling. | 
Tube No. 20 was filled with soil from Santa Clara Valley and was 
packed in the same way as tube No. 1. This tube stood 21 days 
efore sampling. 
Table 7 gives the percentages of moisture as determined in the 
four tubes. 
