146 “On the Measure of 
of the effect produced. The current of ‘thie 
water being uniform, he first ascértains (by 
means of a ‘punip which supplies it) the quan- 
tity which passes in one minute, and ‘then he 
makes various experiments to ascertain the 
greatest effect that can be produced hy that 
quantity, by merely multiplying, after every 
experiment, the weight into the height to 
which it is raised in a mintite. ‘Now the time 
of one ‘minite is taken merely because it is 
known that a certain quantity of ‘water passes 
m that time—the effect which is to be esti- 
mated, being produced in the same ‘time. 
But the time is by no means a ‘necessary 
element in the estimation of the effect ; for the 
height to which a weight is raised by any other 
given quantity of the running water, may 
easily be determined without reference to the 
time, and the result will be the same as when 
the time is considered. “Let p, for example, 
represent the power, that is, a given quantity 
of water moving with a given velocity, and’e 
the effect, or the product of the weight imto the 
height to which it is raised by that power, — 
without any reference to the time in which it is 
raised. “Let p’ be any other quantity of water 
moving (for the sake of simplicity) with the 
saine velocity, and e’ its effect. Now, if the 
power be equally well applied in both cases, 
