A. B. Quinbdy on Water-Wheels. 337 
difference between what he has here given and the original 
sentence ? t the reason is plain. He knew the original 
sentence fixes ae responsibility upon himself; and that by 
leaving out the three interposing ewe: he could shift the 
responsibility upon Messrs. T. & J. Lea 
I 1 now take some notice of ths insinuation of the 
writer of the article in the North American Review, that 
* there is nothing uew in my demonstration. 
Had the writer of this article been acquainted with the prin- 
ciples of the crank problem; or had he understood my de- 
monstration ; he would not have made so unfounded an in- 
sinuation 
The next subject to be noticed, is the assertion that, “ ‘The 
trank is, in any position, merely the arm of a lever, eRe 
only of modifying force without destroying it; a fact know 
sometime before Mr. Quinby’s demonstration of the oak 
problem, namely, in the age of Archimedes.’ 
“The crank i is, in any position, merely the arm of a lever.” 
This is precisely the error committed by Mr. Ward, and by 
O. W. in the London Journal 2 Arts ‘ail Sciences, in their 
attempts to solve the crank pro 
In the lever, the direction of the force is always the same, 
and the intensety always constant 
In the crank, the direction of the force varies continually, 
and the intensity is not, for any portion of time, constant. 
If Archimedes considered the crank ‘‘merely the arm rab a 
lever,” it is sufficient proof that he knew nothing about 
problem 
I shall now conclude this reply by expressing my regret 
that a subject so epeeemne’y plain should have occupied so 
much room in a scientific Journal. 
The course | have adopted and pursued has appeared to 
me necessary, not only in referenee to myself, but in reference 
to the public. A. B. QuINBY- 
August 5, 1826. 
* By leaving out these three interposing members, the Arst member A be- 
comes the antecedent of the proroun, as [ which. | 
VOL. XI.—NO 43 
