36 



BULLETIN 835, U. S. DEPARTMENT OF AGRICULTURE. 



From figure 5 it is seen that the curves for the movement of mois- 

 ture have the same parabolic form as the curves in the preceding 

 figures. A comparison of these curves with those for the vertical and 

 horizontal flumes shows the importance of gravity in the rate and 

 extent of movement of moisture by capillarity. 



The curves show that the rate of movement of moisture is rather 

 more uniform over an extended period than in the vertical flumes. 



After the first two or three days 



Table 22. — Extent of moisture move- 

 ment in flumes at various times. 



there is a gradual slowing down 

 of the rate of movement from 

 day to day. Where the experi- 

 ment is carried on for 50 clays or 

 more it is observed that the rate 

 of movement is very slow at that 

 time. 



Table 22 gives the extent of the 

 movement of the moisture at 

 various times, in percentages of 

 the movement in 30 days. 



It is observed from Table 22 

 that the relative rate of movement in the first three flumes day by 

 day was about the same. In flume 96, however, the rate of movement 

 of the moisture was relatively not so great during the forepart of 

 the experiment, but that a more uniform rate of movement was 

 maintained throughout. In the first three flumes more than one-half 

 of the total 30-day distance had been traveled in three days, or 'one- 

 tenth of the time, and in two-thirds of the time more than nine- 

 tenths of the 30-day dis 



Number 

 of days. 



Flume. 



30 



58 



76 



96 



1 

 3 

 5 

 10 

 15 

 20 

 30 

 40 

 50 



Per cent. 

 34 

 51 

 59 

 74 

 83 

 90 

 100 

 106 

 112 



Per cent. 

 30 

 53 

 59 

 75 

 84 

 91 

 ino 

 108 



Per cent. 

 30 

 53 

 61 

 75 

 84 

 90 

 100 

 106 

 109 



Per cent. 

 21 

 37 

 48 

 66 

 78 

 86 

 100 









Table 23. — Relative movement of moisture, ~by 

 percentage of movement, in flume 96. 



tance had been traveled. 

 In flume 96 on the third 

 day only about one-third 

 of the distance had been 

 traveled, and it was not 

 until about the sixth day 

 that one-half of the dis- 

 tance had been traveled. 



From Table 23 it is 

 found that on the thir- 

 tieth day the moisture 

 in flume 58 had moved but 40 per cent as far as in flume 96, while in 

 flume 39 the moisture had moved one-half as far as in flume 96. 



All of these flumes when compared with flume 96 show a lesser 

 relative movement during the latter part of the experiment than 

 during the forepart of the experiment. This table shows also that 

 the heavy soil as represented in flume 58 has a much less rapid rate 

 of movement during the forepart of the experiment, but that the 









Flume . 







Number 

 of davs. 

























39 



58 



76 



96 



206 





Per cent. 



Per cent. 



Per cent . 



Per cent . 



Per cent. 



1 



80 



56 



90 



100 



117 



3 



69 



56 



91 



100 



90 



5 



62 



50 



82 



100 



80 



10 



57 



46 



73 



100 



66 



15 



54 



44 



70 



100 



60 



20 



53 



43 



08 



100 



57 



30 



50 



40 



05 



100 







