[ * 34 - ] 
when it was loaded fo as not to admit its making 18 
turns, the wheel was overpowered by its load. 
It is an advantage in pra&ice, that the velocity of 
the wheel ihould not be diminifhed further than what 
will procure fome folid advantage in point of power; 
becaufe, caeteris paribus , as the motion is ilower, 
the buckets mud be made larger ; and the wheel 
being more loaded with water, the ftrefs upon every 
part of the work will be increafed in proportion : 
"The bejl velocity for practice therefore will be Juch , as 
when the wheel here ufed made about 30 turns in a 
minute ; that /r, when the velocity of the circum- 
ference is a little more than 3 feet in a fecond. 
Experience confirms, that this velocity of 3 feet 
in a fecond is applicable to the higheft overfhot wheels, 
os well as the lowed ; and all other parts of the 
work being properly adapted thereto, will produce 
very nearly the greateft effedl poflible : however this 
alfo is certain from experience, that high wheels may 
deviate further from this rule , before they will lofe 
their power , by a given aliquot part of the whole , 
than low ones can be admitted to do ; for a wheel of 
23, feet high may move at the rate of fix feet per 
fecond without loling any confiderable part of its 
power*; and, on the other hand, I have feen a 
wheel of 33 feet high, that has moved very fteadily 
and well with a velocity but little exceeding 2 feet. 
* The 24 feet wheel going at 6 feet in a fecond feems owing to 
the final] proportion that the head (requifite to give the water tire 
proper velocity of the wheel) bears to the whole height. 
IV. Con - 
