132 PHILOSOPHY OF 



Mr. Brande observes, in the last edition of his 

 Manual of Chemistry, page 390, that the exist- 

 ence of nitrogen in nearly all the powerfully 

 detonating bodies, is a singular fact ; and that 

 explosion must remain unexplained until we as- 

 certain the cause of the detonating power of such 

 compounds. He also adds, that at present the 

 phenomena are at variance with the usual expla- 

 nation of the evolution of heat and light during 

 combustion, which have been supposed to be the result 

 of union and condensation, instead of expansion and 

 decomposition. 



The truth is, that in a large majority of cases, 

 combustion, as well as explosion, is attended 

 with expansion of the materials employed. La- 

 voisier, who maintained that gaseous oxygen was 

 the source of heat and light in all cases of com- 

 bustion, supposed that it was always condensed 

 on combining with combustibles. This partial 

 view of the subject has been incorporated with 

 so many works on Chemistry and Natural Phi- 

 losophy, that it has become a very general opi- 

 nion, that oxygen is the only supporter of com- 

 bustion, and the source of heat and light, instead 

 of the bodies with which it unites. 



We have already seen, that during the combi- 

 nation of oxygen with hydrogen, they are both 

 condensed into the liquid state; which conden- 

 sation is attended with the evolution of caloric 

 and light. But a large proportion of the caloric 



