and the Mode of its Communication. 103 



reason to think that the heat which it acquires is*not 

 communicated to it by the flame, but by the wood to 

 which it adheres, which is soon heated by the flame, and 

 even set on fire. 



I cannot refrain from just observing that it- appears to 

 me to be extremely difficult to reconcile the results of 

 any of the foregoing experiments with the hypothesis 

 of modern chemists respecting the materiality of heat. 



Deeply sensible of the insufficiency of the powers of 

 the human mind to unfold the mysteries of nature and 

 discover the agents she employs and their mode of ac- 

 tion in her secret and invisible operations, and being, 

 moreover, fully aware of the danger of forming an at- 

 tachment to a false theory, and of the folly of wasting 

 time in idle speculation, I have ever, in my philosoph- 

 ical researches, been much more anxious to discover 

 new facts, and to show how the discoveries of others 

 may be made useful to mankind, than to invent plau- 

 sible theories, which much oftener tend to misguide than 

 to lead us in the path of truth and science. 



There are, however, situations in which an experi- 

 mental inquirer sometimes finds himself, where it is 

 almost impossible for him to abstain from forming or 

 adopting some general theory for the purpose of ex- 

 plaining the phenomena which fall under his observa- 

 tion, and directing him in his future researches. 



Finding myself in that situation at this time, I beg 

 the attention and, above all, the indulgence of the Society 

 while I endeavour to explain the conjectures I have 

 formed respecting the nature of heat and the mode of 

 its communication. 



Hot and cold, like fast and stow, are mere relative 

 terms ; and, as there is no relation or proportion be- 



