the Heat excited by Friction. 491 



those thick mists which on every side bound the hori- 

 zon of the human intellect ? But how ample and how 

 interesting is the field that is given us to explore ! 



Nobody, surely, in his sober senses, has ever pretended 

 to understand the mechanism of gravitation ; and yet 

 what sublime discoveries was our immortal Newton 

 enabled to make, merely by the investigation of the 

 laws of its action ! 



The effects produced in the world by the agency of 

 Heat are probably y'z^j/ as extensive^ and quite as impor- 

 tant, as those which are owing to the tendency of the 

 particles of matter towards each other ; and there is no 

 doubt but its operations are, in all cases, determined by 

 laws equally immutable. 



Before I finish this Essay, I would beg leave to ob- 

 serve, that although, in treating the subject I have en- 

 deavoured to investigate, I have made no mention of the 

 names of those who have gone over the same ground be- 

 fore me, nor of the success of their labours, this omis- 

 sion has not been owing to any want of respect for my 

 predecessors, but was merely to avoid prolixity, and to 

 be more at liberty to pursue, without interruption, the 

 natural train of my own ideas. 



