40 



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



There was in this set an additional flume inclined downward at 

 an angle of 45°, hut the results from that flume were so near like 

 those of the flume inclined at an angle of 30° downward that the 

 addition of the data from this flume would be confusing without 

 adding to the value of the information. In fact, the flume inclined 

 downward at an angle of 45° was discarded after the third set 

 of experiments, for the reason that it did not add to the information 

 obtained from the flume inclined downward at 30°. 



Figure 6 gives the results of the daily measurements of the move- 

 ment of moisture in the several flumes. Table 30 gives the distance 

 the moisture had moved at different periods of time from 1 to 40 

 days. 



Table 30. — Distance moisture had moved at various times, in flumes placed at 



different angles. 









Flume. 







Days. 





























34 



32 



31 



39 



42 



43 





Inches. 



Inches. 



Inches. 



Inches. 



Inches. 



Inches. 



i 



26.00 



22.05 



20.00 



16.35 



16.75 



15.70 



3 



44.15 



41.30 



33.75 



24.55 



24.40 



20.75 



5 



58. 25 



55.00 



41.20 



28.55 



28.85 



22.82 



10 



91.05 



8.85 



53.30 



35.80 



32. 90 



26.25 



15 



118.65 



105.20 



61. 40 



40.25 



34.65 



28.05 



20 



144.05 



125.45 



66.15 



43.65 



36. 05 



29.40 



30 



181.25 



153.55 



75.80 



48. 40 



37.50 



31.55 



40 





168. 35 



79. 85 



51. 25 



38.75 



33.15 





Table 30 and figure 6 show very strikingly the effect of gravitj 7 on 

 the capillary movement of soil moisture even at the end of the first 

 day. It is obvious that in the horizontal flume the distance the 

 moisture had moved is less than in either of the flumes inclined down- 

 ward and is greater than for those inclined upward. This relation 

 holds true not only for the first day but for all the time up to 40 

 days. The table shows that the movement of moisture is less ex- 

 tended in flumes inclined downward 15° than it is in flumes inclined 

 downward 30°, but that the difference is not nearly so marked as is 

 the difference between the 30° flume and the horizontal one. Flumes 



31 and 32 show very clearly the effect of a relatively slight inclina- 

 tion downward from the horizontal. 



For instance, on the thirtieth day the moisture has moved in flume 



32 a little more than twice as far as in flume 31. The figures pre- 

 sented above and the figures obtained for the flumes inclined down- 

 ward at an angle of 45° indicate that at least after an angle of 15° 

 is obtained the effect of inclination is not nearly so marked, degree by 

 degree, as for the first 15° of inclination. Comparing the horizontal 

 flume with the flume inclined upward, we find that even on the first 

 day the inclination is a marked factor in the extent of the movement 



