18 BULLETIN 1221, U. S. DEPARTMENT OF AGRICULTURE. 
left end of the line. It will also be noticed that no decrease in the 
moisture content is indicated toward the extreme end of the line. 
In explanation of this condition it must be kept in mind that the 
moisture had reached the end of the soil column several days before 
sampling. This condition was not present in the other columns. 
The curve for tube No. 18 is much more regular than those of tubes 
Nos. 17 or 20, and this may be accounted for by the open-jointed tube. 
Referring to Table 7, 1t is found that the average percentage of 
moisture in tube No. 17 is 28.71 per cent, and that this percentage of 
moisture was found between the forty-sixth and forty-seventh inches, © 
or not quite two-thirds the horizontal length of the tube. It is found 
that the greatest percentage of moisture is at the ninth inch, or about 
one-eighth the horizontal length. The moisture content of the last 
inch is about 40 per cent of that of the first inch. Dividing the tube 
into four parts, and commencing with the part nearest the tank of 
of water, the average moisture content is 33.07 per cent, in the first 
19 inches, 31.42 per cent in the next 19 inches, 28.07 per cent:in the 
next 19 inches, and 21.96 per cent in the last 18 inches. The third 
quarter of the tube contains about the same average percentage of 
moisture as the whole tube. The first half of the tube contains about 
56 per cent of all the moisture in the tube. This tube, like the vertical 
tubes, shows the most rapid decrease in moisture percentage, inch by 
inch, in the fourth quarter. 
The average percentage of moisture found in tube No. 18 was 
26.58 per cent. This percentage is slightly more than that found at 
the first inch, and slightly less than that found at the last inch. In 
the upper 41 inches of thé tube there is a trifle more moisture than in 
the lower 40 inches. Dividing this tube into four parts as in the case 
of the previous tube, the average percentage of moisture in the first 
20 inches was 26.56 per cent; in the next 20 inches, 26.63 per cent; 
in the third 20 inches, 26.52 per cent; and in the last 21 inches, 26.57 
per cent. The most that can be said of this tube is to call attention to 
the surprising uniformity of the moisture content throughout the tube. 
The average percentage of moisture found in tube No. 19 was 28.26 
per cent, and this percentage is found at the eighteenth inch, or a 
little more than half the length of the tube. The average percentage 
of moisture found in the first 8 inches was 33.63 per cent; in the next 
8 inches, 30.80 per cent; in the third 8 inches, 26.94 per cent; and 
in the last 7 inches, 20.74 per cent. These averages indicate a rather 
uniform decrease in the moisture content with distance from the 
water. The first 15 inches of the tube contained 55 per cent of all the 
moisture in the tube. 
In tube No. 20 the average percentage of moisture was 27.30 per 
cent, and this percentage was found near the ninth inch, or a little 
more than half the length of the tube. The average percentage of 
moisture found in each fourth of the tube, beginning with the first 
fourth, was 32.33, 30.98, 25.92, and 19.97 per cent, respectively. 
Fifty-eight per cent of all the moisture in the tube was found in the 
first half. 
These four tubes, with the exception of tube No. 18, indicate about 
the same distribution of moisture. It is very evident that in tube 
No. 18 the fact that the moisture had reached the end of the soil 
column before samples were taken influenced the moisture dis- 
tribution. 
