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VII. An Enquiry concerning the Nature of Heat, and the Mode of 
its Communication. By Benjamin Count o/'Rumford, V. P. R. S. 
Foreign Associate of the National Institute of France , &c. 
Read February 2, 1804, 
Heat is employed in such a vast variety of different processes, 
in the affairs of life, that every new discovery relative to it must 
necessarily be of real importance to mankind ; for, by obtaining 
a more intimate knowledge of its nature and mode of action, we 
shall no doubt be enabled not only to excite it with greater 
economy, but also to confine it with greater facility, and direct 
its operations with more precision and effect. 
Having many years ago found reason to conclude, that a 
careful observation of the phenomena which attend the heating 
and cooling of bodies, or the communication of heat from one 
body to another, would afford the best chance of acquiring a 
farther insight into the nature of heat, my view, in all my re- 
searches on this subject, has been principally directed to that 
point ; and the experiments of which I am now to give an ac- 
count, may be considered as a continuation of those I have 
already, at different times, had the honour of laying before the 
Royal Society, and of presenting to the public in my Essays. 
In order that the attention of the Society may not be inter- 
rupted unnecessarily, by descriptions of instruments, in the midst 
of the accounts of interesting experiments, I shall begin by de- 
scribing the apparatus which was provided for these researches ; 
