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geous. To which purpofe the effedt produced from 
every pofition of the wheel, and for the different 
number of the float- boards, fhould be computed ; 
the number which gives the arithmetical mean be- 
tween all thefe effedts, the greateil of all, will be 
that to be chofen, and preferred before what the above 
table indicates. 
It may be fufficiently fatisfadtory to compute only 
the effedt from I to io degrees. Thus, for example, 
for the wheel entirely plunged, we are to find the 
effedt (fig. 7.) 
i° oh OA, 2* on OI and gb, 3°on OH, and fc, 
4* on OG and hd , 5 0 on OF, and pe, 6° on OE, 
7 0 on OD, 8° onOC, and 9 0 on OB. 
After which the wheel returns into the fame 
pofition it had at firft • and we are to divide the 
fum of all thefe effedts by 9, to get the arithmetical 
mean. 
We will next fuppofe the number of fix float- 
boards for the fame cafe of f = o, and compute the 
following effedts. 
i°onOG-|-tfA, 3 0 on OE 4- 7/ c, 5° on OI -j- 
2° OF 4- mb , 4 0 OD 6° OH-(-/ 3 B. 
The fum of all thefe effedts divided by 6 will 
give the effedt of the wheel of 6 float-boards. 
The fame thing, fuppofing the angle 40 degrees, 
or 9 float-boards, and as after a revolution of thefe 
40 degrees, the wheel returns into a fimilar pofition, 
the fame mufl be divided by 4. 
Then for an angle of 30 degrees we are to divide 
by 3, and fo on* 
for 
