in various Siibstanccs. 437 



means of explaining a variety of interesting Phenomena in 

 the Economy of Nature. 







THE confining and directing of Heat are objects of 

 such vast importance in the economy of human 

 life, that I have been induced to confine my researches 

 chiefly to those points, conceiving that very great ad- 

 vantages to mankind could not fail to be derived from 

 the discovery of any new facts relative to these opera- 

 tions. 



If the laws of the communication of Heat from one 

 body to another were known, measures might be taken 

 with certainty, in all cases, for confining it, and directing 

 its operations, and this would not only be productive of 

 great economy in the articles of fuel and cloathing, but 

 would likewise greatly increase the comforts and con- 

 veniences of life, objects of which the philosopher 

 should never lose sight. 



The route which I have followed in this inquiry is that 

 which I thought bid fairest to lead to useful discoveries. 



D 



Without embarrassing myself with any particular theory, 

 I have formed to myself a plan of experimental investi- 

 gation, which I conceived would conduct me to the 

 knowledge of certain facfs, of which we are now igno- 

 rant, or very imperfectly informed, and with which it is 

 of consequence that we should be made acquainted. 



The first great object which I had in view in this in- 

 quiry was to ascertain, if possible, the cause of the 

 warmth of certain bodies, or the circumstances upon 

 which their power of confining Heat depends. This, 

 in other words, is no other than to determine the cause 

 of the conducting and non-conducting power of bodies, 

 with regard to Heat. 



