OPINIONS OF BACON AND DAVY. 3 



In the Novum Organum, and in his Treatise 

 entitled De Forma Calidi, it was maintained by 

 Lord Bacon, (whose opinion has been adopted 

 by a majority of philosophers since his day,) that 

 the very essence of heat is motion and nothing else. 

 In accordance with this doctrine, Sir H. Davy 

 observes, in his Chemical Philosophy, that " the 

 cause of heat is motion, and the laws of its 

 communication are precisely the same as the laws 

 of the communication of motion." But in the 

 Treatise on Life and Death, as also in his Natural 

 History, Bacon maintains that " there is in every 

 tangible body, a spirit or body pneumatical, 

 which fills the pores of all gross bodies : that it 

 is not some virtue, or action, or trifle, but a real 

 and quantitative substance, though rare, invisible, 

 and without weight." Moreover, that this spirit 

 or body pneumatical, was only another name for 

 what Hippocrates and other Greek authors called 

 0p/tov heat, (and sometimes ww^a spirit, y\$ equally 

 manifest from the fact, that Bacon represents it 

 as the cause of evaporation, and of many other 

 effects which are predicable of caloric alone. 

 And Sir Humphrey Davy observes in his Agri- 

 cultural Chemistry, that " whatever theory we 

 adopt, it is certain that there is matter moving in 

 the space between us and the heavenly bodies, capable 

 of communicating heat." It is therefore evident, 

 that neither of these distinguished men can be 

 fairly ranked as advocates of the immaterial 



