159 
3d. A part of the heat flies off in direct rays into the room, 
immediately from the fire, and also from the heated walls 
around it. This is radiated heat. 
Now it is evident that nearly all the heat passing off in 
the two first mentioned ways is actually lost, and does not 
contribute to Warm the room. Count Rumford thinks it 
“ quite certain that the quantity of heat which goes off com¬ 
bined with the smoke, vapor and heated air, is much more 
considerable, perhaps three or four times greater than that 
which is sent off from the fire in rays . 39 And with respect 
to the conducted heat , I am confident that of this also, a 
greater quantity passes away through the walls in contact 
with, and near the fire, than is thrown into the room by radi¬ 
ation. The truth of this observation will be sufficiently es¬ 
tablished, when it is found in the sequel, that by the aid of 
this conducted heat a room may be warmed with half the 
ordinary quantity of fuel. It appears then from these data, 
that but a very small proportion of the heat given out in a 
common fire-place comes into the room. The greatest part 
is dissipated without any advantage ; and much fuel is con¬ 
sumed to no purpose. 
Count Rumford, speaking of the radiated heat issuing from 
a fire, says, “ Yet small as the quantity is of this radient 
heat, it is the only part of the heat generated in the combus¬ 
tion of fuel burnt in an open fire-place which is, or ever can 
be employed in heating a room.” Here, however, in the 
latter part of this remark, the Count evidently labors under 
a great mistake ; for although the latent and insensible heat 
contained in the volatile materials ascending the chimney 
cannot easily be extricated and employed in warming a 
room, yet th sfree and sensible heat carried up by the vapor, 
smoke and air, may be brought back into the room, without 
difficulty, and made to contribute much to its warmth. In 
the Transactions of the Society for the Promotion of Agri¬ 
culture, Arts and Manufactures of this State, published in 
1799, there is an Essay on Warming Rooms, by Simeon 
