16 



BULLETIN" 835, U. S. DEPARTMENT OF AGRICULTURE. 



The diagram indicates that the rate of movement in the lighter soils 

 is more rapid for the first few hours and then slows down much 

 quicker than with the heavy soils. The heavier soils maintain a 

 relatively more uniform variation than the lighter soils throughout 

 the experiment. 



The heavy Idaho soil is an excellent example of those soils having 

 a high capillary power. It shows a steady extended movement and 

 differs widely from the light Idaho soils, as shown by flume 209. 



We find in these soils a variation of nearly 250 per cent in the total 

 distance moved in a period of 30 days. In general, the lighter the 

 soil, the shorter the distance the moisture will move upward in a long- 

 period of time. 



The unnumbered dotted lines upon both the drawings in figure 

 2 represent the movement of moisture in vertical tubes of small diam- 

 eter as found by Loughridge (13). These curves are introduced to 

 show the agreement in results from experiments with small tubes and 

 those from the experiments with flumes at Riverside. The soil used 

 in these small tubes, as indicated by the dotted lines, is an alluvial 

 soil from Gila River Valley. 



Table 1 gives, in percentages, that part of the distance moved in 

 1, 2, 3, 5, 10, and 20 days of the total distance moved in 30 days. 



Table 2 gives the same information in hour periods for the first 

 21 hours. 



Table 1. 



-Daily movement of moisture (distance) in percentage of movement 

 in 30 days. 









Flume. 







Number 



of days. 



























19 



43 



63 



80 



100 



209 





Per cent. 



Per cent. 



Per cent. 



Per cent. 



Per cent. 



Per cent. 



1 



51 



41 



47 



46 



30 



62 



2 



61 



60 



57 



57 



43 



71 



3 



67 



i 66 



62 



62 



51 



76 



5 



74 



73 



65 



70 



59 



83 



10 



84 



82 



76 



80 



77 



89 



20 



94 



93 



89 



92 



92 



94 



30 



100 



100 



100 



100 



100 



100 



Table 2. — Hourly movement of moisture (distance) in percentage of movement 



in 24 hours. 



Number 

 of hours. 



Flume. 



19 



43 



63 



SO 



100 



209 



1 

 2 

 3 

 4 

 8 

 12 

 24 



Per cent. 

 27 

 39 

 52 

 03 

 72 

 S4 

 100 



Per cent. 

 15 

 25 

 45 

 57 

 70 

 80 

 100 



Per cent. 



Per cent. 



Per cent. 

 14 

 29 



Per cent. 

 44 

 58 

 69 

 80 

 81 

 90 

 100 



29 



38 

 56 

 66 

 71 

 S3 

 100 



47" 



55 

 63 



74 

 100 



83 

 100 



