[ i44 ] 
a ratio of the velocity of the power, to the velocity 
of the part rubbing on a dead furface ; as in the axis 
in peritrochio, Tab. XII. Fig. i. If the wheel A be 20 
feet diameter, the axis B 1 foot diameter, the pevets 
f of the axis B 4 inches diameter, and the weight C 
to be raifed by the axis B, 12 tons or 24,000 
pounds 
The power D, in the wheel A, with refpedt to the 
weight C to be raifed on the axis B, is required in a ratio 
of the femidiameter of the wheel A to the femidiame- 
ter of the axis B, which is 4 0 ; therefore the power D— 
1200 pound is fufficient to counterbalance the weight 
C, and the lead: additional power would raifeit, if there 
were noobftrudlion. But the quantity of friction in the 
pevets y, l'uppofed equal to 4 the weight or preifure 
on that part, requires an additional power in the wheel 
A to overcome its refinance, in a ratio of the femidia- 
meter of the wheel A, to the femidiameter of the pevets 
j\ or of the velocity of t he power in the wheel A, to 
the velocity of the part rubbing on a dead furface in 
the pevets f which are 6 °. And as the weight of 
the wheel A, fuppofed 1500 pound, alfo the power D 
1200 pound, required to counterbalance the weight 
C 24,000 pound, in all 26,700 pound; center in the 
pevets f the quantity of fridtion in the pevets j\ 
being equal to 4 the weight, or 13,350 pound hang- 
ing on them, will require a power in the wheel A 
fomewhat more than 220 4 pound to overcome its 
refiftance. And as this additional power E 220 4 
pounds caufes an additional fridtionr=i 10 - 4 pounds, 
it alfo requires a further power K = 1 4 pounds to 
overcome its refinance; but the quantity of fridtion 
proceeding from thence, need not be ellimated in a 
.calculation of this nature. 
As 
