1821.] Causes of Calorific Capacity, Latent Heat, §c. 265 



be explained on the simple principle of adaptation. The less 

 the adaptation of the corpuscular parts in the solid, and the 

 greater in the consequent gas, the more easily the body will 

 explode. 



This explanation will hold good equally in the general outline, 

 whether the explosion leaves a residuum, as by Mr. Robins's 

 experiments it appears the tiring of gunpowder does, or whether 

 the body in the explosion combines with any part of the atmo- 

 sphere, which, it would seem by the increased weight of the 

 gaseous product, aurum fulminans does. The only objects I 

 nave had in view are to showfc hat a solid may be converted into 

 a gas having particles of a greater magnitude, and that the 

 explosion of one small part of the body is enough to explode the 

 whole ; both of which objects are independent of the above 

 peculiarities. 



Iu all cases I think it will be found, where bodies explode in 

 this way by communication, that the explosion will be accompa- 

 nied with an increase of temperature, unless any deposition 

 might operate to the contrary, of which it would be difficult to 

 form an idea without experiment. 



From the views I have taken, it appears that all changes 

 which produce an increase of particles out of the same quantity 

 of matter, must be attended with a diminution of temperature ; 

 and all changes which produce a diminution of particles in the 

 same quantity of matter, with an augmentation of temperature. 

 Conversely all changes of temperature arising from any change in 

 the constitution or nature of the body, are accompanied with an 

 aggregation or decomposition in the particles ; that is, with a 

 chemical change ; for chemical changes do not consist in any 

 alteration of the component atoms, but merely in new arrange- 

 ments and associations of them. But notwithstanding such 

 changes of temperature (which, to distinguish them from natural 

 elevations and depressions, may be called corpuscular changes 

 of temperature) are invariably attended with a chemical change 

 in the body or its particles, it is not conversely a universal rule, 

 that chemical changes produce a corpuscular change of tempera- 

 ture. In other words, the rule that has been generally given by 

 chemical writers ; namely, " that all chemical changes produce 

 an alteration of temperature," is not a law of nature, nor neces- 

 sarily true in all cases ; but rather an extensive case of a univer- 

 sal rule. If the change has not increased or diminished the 

 number of particles in the body, or the sum of them in the 

 bodies, if more than one body, the temperature will not be 

 affected, however great an alteration may have taken place in 

 the colour, density, and chemical properties, of the body or 

 bodies. But the case of a perfect equality of temperature before 

 and after the change requires so nice a balance in the numbers 

 of the particles, and so small a deviation in the ratio of these 

 numbers would produce so considerable a difference in the pre- 



