t I0 7 ] 
and from all doubts, arifmg from the different mea- 
fure of fpouting waters, afiigned by different authors. 
On the other hand, the fum of the weights raifed 
by the action of this water, and of the weight re- 
quired to overcome the friction and refinance of the 
machine, multiplied by the height to which the 
weight can be raifed in the time given, the product 
will be equal to the effedl of that power j and the 
proportion of the two products will be the propor- 
tion of the power to the ejf'cfl : fo that by loading 
the wheel with different weights fucceffively, we 
fhall be able to determine at what particular load, 
and velocity of the wheel, the effedt is a maximum. 
The manner of finding the real velocity of the 
water, at the inftant of its ftriking the wheel ; the 
manner of finding the value of the fridtion, refift- 
ance, &c. in any given cafe j and the manner of 
finding the real expence of water, fo far as con- 
cerns the following experiments, without having re- 
courfe to theory ; being matters upon which the fol- 
lowing determinations depend, it will be necefiary 
to explain them. 
To determine the Velocity of the Water fr iking the 
Wheel, l 
It has already been mentioned, in the references 
to the figures, that weights are raifed by a cord 
winding round a cylindrical part of the axis. Firff, 
then, let the wheel be put in motion by the water, 
but without any weights in the fcale ; and let the 
number of turns in a minute be do: now it is evi- 
dent, that was the wheel free from fridtion and refin- 
ance, that 60 times the circumference of the wheel 
P 2 would 
