[ «>8 ] 
would be the fpace through which the water would 
have moved in a minute ; with that velocity where- 
with it ftruck the wheel : but the wheel being in- 
cumbred by fridtion and reliftance, and yet moving 
60 turns in a minute, it is plain, that the velocity 
of the water muft have been greater than 60 cir- 
cumferences before it met with the wheel. Let 
now the cord be wound rdwft the cylinder, but 
contrary to the ufual way, and put a weight in 
the fcale ; the weight Co difpofed (which may be 
called the counter-weight) will endeavour to aflift the 
wheel in turning the fame away, as it would have 
been turned by the water : put therefore as much 
weight into the fcale as, without any water, will 
caufe it to turn fomcwhat fafter than at the rate of 
60 turns in a minute ; fuppofe 63 : let it now be 
tried again by the water, aflifted by the weight ; the 
wheel therefore will now make more than 60 turns; 
fuppofe 64 : hence we conclude the water hill ex- 
erts fome power in giving motion to the wheel. Let 
the weight be again increafed, fo as to make 64-1. 
turns in a minute without water : let it once more 
be tried with water as before ; and fuppofe it now 
to make the fame number of turns with water as 
without, viz. 64 t = hence it is evident, that in this 
cafe the wheel makes the fame number of turns in 
a minute, as it would do if the wheel had no fric- 
tion or reliftance at all ; becaufe the weight is equi- 
valent thereto ; for was it too little, the water would 
accelerate the wheel beyond the weight ; and if too 
great, retard it j fo that the water now becomes a 
regulator of the wheel’s motion ; and the velocity 
of its circumference becomes a meafure of the velo- 
city of the water. 
In 
