128 



NEW YORK STATE MUSEUM 



column (1) in the following- tabulation. Since the water surface 

 area is 20 square miles, it becomes 20/5828 of the whole, or 1/292. 

 Hence water surface evaporation is 1/292 or 40 inches, and mak- 

 ing the computation for each month, we have the quantities as 

 per column ( 2) : 



Total evaporation and evaporation per square mile of water surface in 



Muskingum basin 



Month 



(i) 



Total 

 evapora- 

 tion 



(2) 

 Evapora- 

 tion 

 per square 



milG of 

 water sur- 

 face 





1.00 



0.0034 



February 



1.10 



.0037 







.UOob 





3.00 



.01029 



May v.,..- 



4.60 



.01578 







.01938 



July 



6.10 



.02092 





5.60 



.01921 





4.15 



.01423 



October 



3.35 



.01149 





2.25 



.00772 





1.50 



.00514 





40.00 





With some allowance for percolation, 



leakage, etc. the total is 



taken at 0.40 of an inch per year. Analyzing the first period, we 

 find that for 24 months there was an average flow of 0.76 inch 

 per month, for 12 months an average flow of 0.67 inch, and for 

 9 months an average flow of 0.43 inch. 



The second low-water period was from May, 1891, to January, 

 1893, inclusive, a period of 21 months, during which time the net 

 runoff was 17.2 inches, yielding for the whole 21 months an aver- 

 age of 0.82 inch and for 7 months an average of 0.36 inch. 



The most extreme low water period was from April, 1894, to 

 November, 1895, inclusive, a period of 20 months, during which 



