340 Remarks on Mr. Quinby’s Crank Problem. 
fore, being the product ofa multiplication, differs from degree 
of power as superficial differs from linear m 
This distinction being clearly apprehended, it is manifest 
that no degree of power, however great, can ever constitute 
any quantity of power, pen small. It is therefore evi- 
dent that one cannot be compared with the other ; and that 
no course of | reasoning with regard to one only, can justify 
any conclusion with regard to the other. Now here lies the 
‘eause of Mr. Quinby’s failare to prove the point at which he 
aimed. He instituted a course = reasoning which involves 
necessarily only power in de ; but in the conclusion, he 
raws an inference, necessarily ‘edt power in quantity. 
Of precisely the same kind | is the error of his opponent in the 
last number. 
The effect of a steam engine is always motion againgt a re- 
sistance. Such an effect manifestly volves two attributes, 
viz. degree of -aiiehats and distance, and is therefore in 
yr consequently, i it can be compared with the sad 
which produces it, only in quantity. We cannot therefore de- 
termine, whether, in a steam engine, the power exerted on 
the piston produces its due effect on the crank, by institut- 
ing a comparison between the degree of force exerted on the 
pee: and the mean tendency to rotation produced thereby, 
crank ; for such a comparison would be in degree on- 
ies ; and would leave entirely out of the account, the respec- 
tive onium through which each moves ; which are as im- 
portant constituents, both of the power and effect, as is the 
degree of force. 
A Now to establish the truth of Mr. Quin- 
crank, which effectually tends-to the pro- 
duction of rotation, is equal to the quan- 
tity of power exerted by the steam on 
the piston. 
To do this, let us suppose, with Mr. 
