51£ APPARATUS FOR THE 



there was not the slightest indication of the presence 

 of electric fluid in the Leyden phial. 



Having found that the first hypothesis does not 

 hold true, we are led to adopt the second, which as- 

 cribes the phenomena to condensed caloric. 



Under this view of the subject, we have a more 

 complicated agent to trace. In the electric theory, 

 we had only one source of the fluid, in an ingredi- 

 ent of the fulminating powder, and we had ready 

 tests for its nature and presence : but we have vari- 

 ous sources from which the caloric may arise ; and 

 our means for ascertaining its nature and presence 

 are sometimes rather inconclusive. In the present 

 case the caloric may arise from one or more of five 

 different sources. 



1. It may be disengaged from the fulminating 

 powder, by a change of capacity induced by the blow 

 of the hammer ; or probably from a partial decom- 

 position of the union of the substances with their 

 natural caloric. 



% It may arise from the combustion of the ingre- 

 dients of the powder, in contact with the compress- 

 ed air. 



3. The air of the tube may give out caloric, being 

 condensed by the gasseous bodies liberated at the 

 top. 



4. The air in the cap at the top of the tube, may 

 give out caloric, when compressed between the cap 



