350 Canon Moseley on the steady Flow of a Liquid. 



(2) which, although not neglected in equation (7), is neglected 

 in equation (12). It represents the work carried away by the 

 liquid which flows from the pipe in each unit of time. By the 

 leaving out of these terms V x + U 2 from the right-hand member 

 of equation (2), it becomes an ^equality. To restore its 

 equality, its left-hand member U must be diminished • that is to 

 say, h must be assumed to be less than it really is. Let it 



become -, where y is an unknown function of \J 1 and U 2 such 



that the substitution of - for h in the value of U will restore 



7 

 the equality which has been destroyed in equation (2) by omis- 

 sion of Uj -f- U 2 and correct the error which has resulted there- 

 from in equation (12). The value of 7 is shown by experiment 

 (see Tables I., II., III.) to vary so slowly with the diameter of 

 the pipe as to be nearly the same for diameters from 0*188 metre 

 to 0-2447 metre. It becomes sensibly less, however, for dia- 

 meters from 0-297 metre to 0*5 metre. For the former dia- 

 meters, its value is about 225 ; for the latter, as shown by the 

 following Table, the values of y, 1-5 and 1, agree more nearly 

 with experiment. 



Table IV. 



Index 

 number. 



By experiment. 



By theory, v=v e-i'5>'. 



Diameter =0-297 metre. 



r. 



r. 



0-1023. 



0102. 



0-052. 



0. 



01023. 



0-102. 



0052. j 0. 



v 3 . 



v 2 . 



v v 



v . 



v 3 - 



v 2 . 



v v 



V 



# 



* 



0-355 

 1-236 

 1-665 

 2-365 



0-355 

 1-230 

 1-666 

 2-355 



0-410 

 1-356 

 1-839 

 2-590 



0-435 



1-418 

 1-931 



2-708 



0-373 

 1-216 

 1-656 

 2-323 



0-374 

 1-217 

 1-657 

 2-324 



0-403 

 1-344 



1-787 

 2-505 



0-435 

 1-418 

 1-931 



2-708 



Diameter =0-5 metre. 



Index 

 number. 



By experiment. 



By theory, v=v e~r. 



r. 



r. 



01723. 



0170. 



0-90. 



0. 



0-1723. 



0170. 



0090. 



0. 



v 3 . 



v 2 . 



v x . 



v Q . 



v 3 . 



v 2 . 



v v 



0-571 

 0-919 

 1-319 



192. 

 194. 

 197. 



0-475 

 0-795 

 11197 



0-477 

 0-796 

 1115 



0-535 

 0-869 

 1-241 



0-571 

 0-919 

 1-319 



0-481 

 0-773 

 1111 



0-482 

 0-7/6 

 1-112 



0-522 

 0-840 

 1-205 



* No index number is given to these experiments in the work ofM. Darcy. 

 They are to be found at p. 143. 



