HTDH.AULIC INVESTICV.VMOXS'. 



10.9 



(Mean -129=L. 1-346 098=L. 1'254) 



tf. at 60°. 



Dl T Bt!AT. 



(Mean -029 



13882 

 452100 



747 

 1063 



(Mean •0l7=L.l , 041 009=L. 10S 





it appears from this comparison, that in the forty experi- Accuracy of 



ments extracted from the collection, which served as a basis the two for ~ 



, mulx com- 



for Dubuat's calculations, the mean errour of his formula pared, 



is T ' T of the whole velocity, and that of mine J T only ; but 

 if we omit the four experiments, in which the superficial 

 velocity only of a river was observed, and in which I have 

 calculated the mean velocity by D ubu at' s rules, the mean 

 errour of the remaining 36 is ^ according to my mode of 

 calculation, and -^y according to Mr. Dubuat's; so that on 

 the whole, the accuracy of the two formulae may be con- 

 sidered as precisely equal with respect to these experiments. 



In 





