156 



NEW YORK STATE MUSEUM 



1888 — Inches 



Storage 3.50 



Growing 1.15 



Replenishing 1.00 



Yearly total 5.65 



1889— 



Storage 3.10 



Growing 3.95 



Replenishing 1.05 



Yearly total : 8.10 



Mean 5.63 



Comparing the foregoing mean of 5.63 inches with the mean of 

 runoff from sod, bare soil and cultivated soil, as per table No. 33, 

 we see that the mean of all is 7.91 inches. If, however, we omit 

 the years 1886 and 1889, which appear to be abnormally high, we 

 find that the mean of all is 5.77 inches, which compares very 

 closely with the mean found by the computation. Undoubtedly 

 there is some inaccuracy in the record of the drain gages, as well 

 as in the record of the precipitation, and the foregoing computa- 

 tion is given chiefly to show that with good data the computa- 

 tion of runoff from a rainfall record can be made with consider- 

 able precision. 



In the Sixth Annual Report of the Geneva Agricultural Experi- 

 ment Station (1887) it is stated that discussion of the results 

 from these drain gages has been deferred, hoping that sufficient 

 data would reconcile the discrepancies existing between the drain 

 gage results and what apparently takes place in outside soils. 1 In 

 regard to the discrepancies, the foregoing discussion as to over- 

 sight in precipitation records largely explains them and probably 

 further discussion is unnecessary. 



Nevertheless, it should be stated thai in an ordinary drain gage, 

 since the soil within the gage Is not in connection with a perma- 

 nent water table, the acquisition of water by capillarity from 



'Report of Agricultural Experiment Station at Geneva for 1887, p. 380. 



