f I2 + ] 
cular fweep being adapted thereto, of fuch a length, 
that one float entered the curve before the preceding 
one quitted it, the efFedt came fo near to the former, 
as not to give hopes of advancing it by increafing 
the number of floats beyond 24 in this particular 
wheel. 
PART II. 
Concerning Overshot Wheels. 
Read May 24, TN the former part of this eflay, we have 
X confldered the impulfe of a confined 
ftrearn, adting on Underjhot Wheels. We now pro- 
ceed to examine the power and application of water, 
when adting by its gravity on Overjleot Wheels. 
In reafoning without experiment, one might be 
led to imagine, that however different the mode of 
application is ; yet that whenever the fame quantity 
of water defeends thro’ the fame perpendicular fpace, 
that the natural effedtive power would be equal ; 
fuppofing the machinery free from fridtion, equally 
calculated to receive the full effedl of the power, and 
to make the mod of it : for if we fuppofe the height 
of a column of water to be 30 inches, and refling 
upon a bafe or aperture of one inch fquare ; every 
cubic inch of water that departs therefrom will ac- 
quire the fame velocity or momentum , from the 
uniform preflure of 30 cubic inches above it, that 
one cubic inch let fall from the top will acquire in 
falling down to the level of the aperture ; viz. fuch 
a velocity as in a contrary diredtion would carry it to 
the 
