CHEMICAL FORCE OF THE ACIDS. 247 



and still more absurd to confound attraction with 

 the innate properties of ponderable matter. 



That the strong acids owe their activity and 

 chemical properties to caloric, is evident from 

 the following facts : 



1 . They all become solid by the abstraction of 

 caloric, when their burning caustic properties are 

 greatly diminished, together with their power of 

 dissolving other solid bodies. 



2. Their power of dissolving metals is greatly 

 augmented by raising their temperature. 



Concentrated sulphuric acid acts very feebly 

 on iron, until made boiling hot. Copper is dis- 

 solved rapidly by sulphuric acid when raised to 

 the boiling point. Lead, which is not affected 

 by sulphuric acid when cold, is readily dissolved 

 by it at 212 F. Its solution in nitric and acetic 

 acids is also greatly augmented by raising their 

 temperature. But it would not be philosophical 

 to maintain that an agent which is indispensable 

 to all fluidity, and which increases the solvent 

 power of acids, is different from the primary and 

 efficient cause of solution.* 



3. When the earthy, alkaline, and metallic 



* The first part of the process by which metals are dissolved 

 in the strong acids, is decidedly one of combustion. For ex- 

 ample, when nitric acid is poured upon plates of iron, copper, 

 &c. a portion of its oxygen unites chemically with them, by 

 which they are converted into oxides, with disengagement of 

 heat, (as when poured on volatile oils, and other inflammable 

 bodies,) after which, they are dissolved like salts in water. 



