9 8 Count Rumford’s Inquiry concerning 
What is heat ? — Is there any such thing as an igneous 
fluid? — Is there any thing that can with propriety be called 
caloric ? 
We have seen that a very considerable quantity of heat may 
be excited in the friction of two metallic surfaces, and given 
off in a constant stream or flux, in all directions , without inter- 
ruption or intermission, and without any signs of diminution, 
or exhaustion. 
From whence came the heat which was continually given off 
in this manner, in the foregoing experiments ? Was it furnished 
by the small particles of metal, detached from the larger solid 
masses, on their being rubbed together ? This, as we have al- 
ready seen, could not possibly have been the case. 
Was it furnished by the air ? This could not have been the 
case; for, in three of the experiments, the machinery being kept 
immersed in water, the access of the air of the atmosphere was 
completely prevented. 
Was it furnished by the water which surrounded the ma- 
chinery ? That this could not have been the case is evident ; 
first , because this water was continually receiving heat from 
the machinery, and could not, at the same time, be giving to , 
and receiving heat from, the same body ; and secondly , because 
there was no chemical decomposition of any part of this water. 
Had any such decomposition taken place, (which indeed could 
not reasonably have been expected, ) one of its component elas- 
tic fluids (most probably inflammable air) must, at the same 
time, have been set at liberty, and, in making its escape into 
the atmosphere, would have been detected ; but, though I fre- 
quently examined the water, to see if any air bubbles rose, 
up through it, and had even made preparations for catching 
