ad 
298 M. P.8. Girard on, Navigable Canais. 
And, since the last level Be of the canal, is the river 
in which it terminates, and which may be considered as an 
indefinite reservoir whose level is invariable, whatever 
may he the number of boats which ‘enter it, we have w= 
0, w’=9, and, consequently, after the passage of any tum: 
ber (N) of boats ; ae 
5, $2, 4. M04. ai 4) esa, a= 
BAe Ae yay t+ 2 a ~ ta} tu," ul" Fu," S pehas 
N ‘ ‘ 
Bs uy 3,04 
whence we see that after the passage of any number (N) 
of boats in the-canal, the sum-of the primitive falls of all 
the locks ¢,-Pa’,,+-2',,, +8. is Increased only by the quan- 
tity w+", +-w",+, &c. which has been raised to the sum- 
mat eve RY) *e0neiia se li 
What we have said of thé lower Jével which terminates 
the canal, will apply equally to atiy intermediate level 
which is maintained at a constant ‘height, by means of @ 
feeder, whatever might be the activity of the navigation. 
of a navigable canal, wil! depend on the superficial extent, 
and ‘on the rise and fall which separates them respective- 
, This point established, it is evident that the elevations 
mu, U',, wy wu’ produced by the descent of the first boat, 
