A. B. Quinby on Water-Wheels. 333 
with extraordinary modifications. No man is better able 
than you are to solve the phenomenon, 
I have the honour to be, with esteem, and very respectfully 
yours, JosiaH MEIGs. 
The Hon. S. L. Mircuiti, New-York. 
Arr. XII1.—On Pitch-back and Breast-Wheels. By Mr. 
A. NBY. 
Pror. SILLIMAN, 
Dear Sir,—In my letter of Feb. 12, 1825, I promised 
to communicate a paper for a subsequent number of this 
Journal, applying. my theory of the Overshot-Water-Wheel 
to the Pitch-back and Breast-Wheels. I now redeem that 
pledge. 
Before offering my present paper, however, it is proper to 
remark, that a Pitch-back-Water-Wheel is one that receives 
the water at any point between the top of the wheel and the 
