1 62 On Cal(X)ic, and the Heat evolved during Comhustion. 



that gunpowder, containing one of these fluids in large 

 quantity in potash, and the other to a requisite extent in 

 sulphur, it will not be surprising, that gunpowder should 

 burn in vacuo, nor again that it should give out so much 

 heat and light on deflagration. These principles not 

 only account for every phajnomenon of combustion re- 

 lative to gunpowder, and by applying them to combustion 

 by acids, &c., likewise, but at the same time for the heat 

 emitted during combustion in air. Whereas, to reconcile 

 Lavoisier's system, wc are obliged to suppose an 'unnatural 

 chemical union of oxygen, different from its general pro- 

 perties, for which there is no other ground, than the con- 

 venience it is of, only to deceive ourselves, by regarding as 

 a property of nature, what is in reality only a property of 

 human imagination, and which, if persisted in, must effectu- 

 ally put a stop to this branch of science. 



It must be obvious that these principles will in a most 

 simple and beautiful manner account for the light and heat 

 produced by electrical experiments and friction. To enter in- 

 to particulars would exceed the, limits of this paper. I shall 

 therefore conclude with a view of the process of revifica- 

 tion or decombustion. Suppose the body acted upon is iron ; 

 A quantity of resinous fluid unites with the metal, and the 

 oxygen of the oxide of iron is .separated in the process; it is 

 therefore as strictly a chemical union as that effected in com- 

 bustion. If we examine the process for therevification of ores, 

 we find it peculiarly adapted to produce this decomposition. 

 A layer of charcoal, then a layer of oxide, is alternately depo- 

 sited. The heat that is first produced by setting fire thereto^ 

 carries off the oxygen of the charcoal in carbonic acid gas : 

 the carbon thus heated has an affinity for, and combines 

 with, oxygen. When, therefore, the oxygen of the charcoal 

 is exhausted, it unites with, and carries off in gas, the oxy- 

 gen of the ore, at the same time that the resinous electric 

 fluid of the carbon unites with the atoms of the metal. 

 Thus it is that fire both burns and unburns substances. The 

 fire acts no otherwise than by placing the particles of carbon 

 and oxide in a situation in which they have power to act on 

 each other: one part only of th« combustibility of the char- 

 coal 



