LETTER 
ON 
CMIMNEY FIRE-PLACES, 
ADDRESSED TO 
ROBERT R. LIVINGSTON, L. L. D. 
President of the Society for the Promotion of Useful Arts s 
BY BENJAMIN PE WITT, M. D. 
Professor of Chemistry in the University of the State of New-York. 
m?000$&000*** 
Albany , Dec . 10^/z, 1810 c 
Dear Sir, 
I THINK I mentioned to you last winter that I had 
fitted up a fire-place in a very advantageous manner,by which 
much fuel was saved and a great increase of heat produced. 
The return of the cold season brings this subject forcibly to 
my mind; and where fuel is expensive every improvement 
In this branch of domestic economy becomes of public im¬ 
portance. I propose then in this letter to give you a descrip¬ 
tion of several fire-places constructed on the principle ap¬ 
plied to mine ; together with some observations on the use¬ 
fulness and importance of that principle, when put into suc¬ 
cessful operation. 
Whenever a fire is kindled in an ordinary open fire-place ? 
the heat generated by the combustion of the fuel escapes in 
three different ways : 
1st. A considerable quantity ascends the chimney in a 
state of combination with the air, vapor and smoke created 
by the fire. This is called combined heat . 
2d. A large portion is absorbed by the hearth, back and 
sides of the fire-place, and is coaveyed away through the 
walls by means of the conducting property of the materials 
composing it. This is called conducted heat. 
