2*22 LIGHT OF COMBUSTION. 



its own particles, and is attracted by ponderable 

 matter. By its self- repulsive property, caloric 

 dissolves, expands, and decomposes all things: 

 by its affinity for ponderable matter it contracts, 

 unites, and holds together all things thus caus- 

 ing the centrifugal and centripetal forces of 

 nature. By the agency of heat, chlorine, fluo- 

 rine, iodine, and bromine, are made to combine 

 with sulphur, phosphorus, metals, &c. by which 

 new compounds are generated, termed chlo- 

 rides, fluorides, iodides, and bromides. When 

 carbon, sulphur, phosphorus, and other bodies 

 are heated with metals, they are converted into 

 carburets, sulphurets, and phosphurets. By the 

 agency of solar heat the oxygen of the atmos- 

 phere is made to combine with the elements of 

 dead animal and vegetable matter, which are 

 thus constantly undergoing a, slow combustion 

 or dissolution during summer, termed putrefac- 

 tion ; and by which new combinations are 

 formed. 



It has been said, that iron and other metals 

 may be kept in a state of ignition for unlimited 

 periods of time without any loss of their sub- 

 stance. Nothing could be more unfounded. 

 The truth is, that the incandescence or lumi- 

 nosity of all bodies, cater is paribus, is in pro- 

 portion to temperature ; while they are volati- 

 lized and dissipated in the same ratio. Ignition 

 is only a modification of combustion. When 



