42 



BULLETIN 835, IT. S. DEPARTMENT OF AGRICULTURE. 



of the soil moisture. At the end of the thirtieth day we find that the 

 flume inclined upward at 45° gives only one-half as extensive a 

 movement of the soil moisture as the horizontal flume, and the flume 

 inclined upward at an angle of 30° gives about two-thirds as exten- 

 sive a movement of the soil moisture. Taking the four flumes, the 

 horizontal, the one inclined upward at 30°, the one inclined upward 

 at 45°, and the vertical flume, the extent of soil moisture in distance 

 within these flumes is in the order given, with the greater extent of 

 moisture in flume 3f or the horizontal- flume. 



To show more clearly the effect of gravity upon the movement of 

 moisture by capillarity, Table 3f gives the data of Table 30 in per- 

 centages of movement in the flume inclined downward 30° : 



Table 31. — Relative movement of moisture in flumes, expressed in percentages 

 of movement in flume 34- 









Flume. 







Number 

 of days. 

























3! 



32 



31 



39 



42 



43 





Per cent. 



Per ceni. 



Per cent. 



Per cent. 



Per cent. 



Per cent. 



1 



100 



So 



80 



63 



64 



60 



3 



100 



93 



76 



56 



00 



47 



5 



100 



94 



71 



49 



49 



39 



10 



100 



90 



59 



39 



36 



29 



15 



100 



90 



52 



33 



29 



24 



20 



100 



87 



46 



30 



25 



20 



30 



100 



85 



42 



26 



21 



12 



On the thirtieth day Ave find that the moisture in the vertical flume 

 has moved but 12 per cent as far as in flume 34 and in flume 42 it has 

 moved 21 per cent as far; in flume 39, 26 per cent as far; in flume 

 32, 85 per cent as far; and in flume 31, 42 per cent as far. It is 

 obvious that the above percentages are comparable to the angles of 

 inclination relative to the horizontal. This table brings out even 

 more strikingly the effect of gravity in the movement of soil moisture 

 by capillarity. 



Table 32 gives the relative distance the moisture had moved in the 

 several flumes for different periods of time, based on the distance the 

 miosture had moved in 30 days in the respective flumes. 



Table 32. — Capillary 'movement of 'moisture at various times, in percentage of 

 the movement in 30 days. 









Flume. 







Number 

 of days. 



























34 



32 



31 



39 



42 



34 





Per cent. 



Per cent. 



Per cent. 



Per cent. 



Per cent. 



Per cent. 



1 



14 



14 



26 



34 



45 



50 



5 



32 



36 



54 



59 



1 1 



72 



10 



50 



53 



70 



74 



88 



83 



15 



65 



68 



81 



83 



92 



90 



20 



79 



79 



87 



90 



90 



93 



30 



100 



100 



100 



100 



100 



100 



