%% CALORIC. 



their termination in ate : thus sulphuric acid and 

 potash form sulphate of potash, and so of all the 

 rest. 



The terms, bi-sulphuret, bi-phosphoret, bi-sul- 

 phate, &c. denote that these compounds contain 

 twice as much sulphur, phosphorus, sulphuric 

 acid, &c. as the sulphuret, phosphoret, sulphate, &c. 



CALORIC. 



CALORIC, or the matter of heat, is generally con- 

 sidered as a peculiar elementary substance. It 

 cannot be ascertained to have any weight, a body 

 when heated not being heavier than before. 



A distinction is made between caloric, or the 

 matter of heat, and the word heat when considered 

 as a sensation. The sensation of heat, or sensible 

 heat, is the effect produced upon our organs by the 

 motion of caloric disengaged from the surrounding 

 bodies. When we touch a cold substance, the 

 caloric, which exists in unequal quantities in dif- 

 ferent bodies, but which always tends to be in equi- 

 librio in all bodies, passes out of the hand into the 

 body, which feels cold, because at the time there 

 was less free caloric in the substance than in the 

 hand ; and as we have lost heat, we feel the sensa- 

 tion of cold: cold being, not any thing positive, but 

 merely the want of heat. The contrary happens 

 when we touch a warm body j the caloric then in 

 passing into the hand, gives the sensation of 

 warmth. If the hand and the body touched be of 

 the same temperature, or very nearly so, we re- 

 ceive no impression either of heat or cold, because 

 there is no motion of caloric. 



By free caloric, we mean that which is not com- 

 bined with any other body. But, as caloric has a 



