HYDROLOGY OF NEW YORK 



4G3 



1 or 2 as giving more nearly the actual flows, and accordingly 

 the flows have been computed by the use of the said coefficients. 

 By way of showing the relation between the flows as per Francis's 

 formula and by Corn-ell experiments Nos. 1 and 2, the following 

 tabulation is submitted, the last column giving the difference 

 between Francis's formula and the mean of experiments Nos. 1 

 and 2 as a per cent of the flow by Francis's formula : 



Head on Crest 

 Feet 



(1) 



0.5 



1.0 



1.5 



2.0 



2.5 



3.0 



3.5 



4.0 



4.5 



5.0 



Cubic feet per second 

 per foot of crest 



Difference 



Difference 

 as a per cent 



Cornell 

 experiments 

 Nos. 1 and 2 



Francis's 

 formula 



of columns 

 (2) and (3) 



of flow by 

 Francis's 

 formula 



(?) 







(a) 



(4) 



(5) 



*1 .17 



... 



1 .18 



0.01 



0.8 



*3.44 



3.33 



*0.11 



3.3 



*6.59 



6.12 



0.47 



7.7 



10.50 



9.42 



1.08 



10.4 



14.59 



13.16 



1.43 



10.8 



19.12 



17.30 



1.82 



10.5 



24.20 



21.90 



2.30 



10.5 



29.66 



26.64 



3.02 



11.3 



35.40 



31.78 



3.62 



11.4 



41.46 



37.20 



4.26 



11 .5 



* Mean taken 



In passing, it may be remarked that the flood-flows of Black 

 river have been computed by either Bazin's coefficients or by the 

 coefficients deduced from the Cornell University experiments. 



In its course from the headwaters in Hamilton county to Lake 

 Ontario at Dexter, Black river has topographically three distinct 

 subdivisions: (1) The upper valley above Lyon Falls; (2) the mid- 

 dle valley stretch from Lyon Falls to Carthage, and (3) the lower 

 valley with rapid fall from Carthage to Black river bay. The 

 second division, from Lyon Falls to Carthage, is a broad, flat 

 valley. 



The catchment area of the whole river above Dexter is 1930 

 square miles ; above Carthage, 1812 square miles, and above the 

 mouth of Moose river, 463 square miles. The following are the 

 areas of the principal tributaries: Deer river at mouth, 102 

 square miles; Beaver river at mouth, 337.5 square miles; Moose 



