DISCHARGING OF ORDNANCE, 



513 



in the one direction, and the gaseous ingredients of 

 the powder in the other direction. And, 



5. The caloric may arise from the rapid move- 

 ment of the gaseous substances along the brass 

 tube. 



Such are the probable sources from which the ca- 

 loric may be derived ; and we may admit that they 

 all so far unite to disengage it. 



But, again, when we consider the nature of the 

 caloric, the simplicity of the electric fluid is also 

 lost. The condensed caloric may be attached to some 

 disengaged gaseous fluid ; it may proceed by vi- 

 brations ; or it may exist by itself, quite distinct 

 for the momentary period of its being visible, as it 

 were in an insulated form, somewhat analogous to 

 radiation. 



From the various results I have obtained in my 

 experiments, and particularly in those undertaken 

 for the express purpose, I am rather inclined to 

 adopt the last of these conjectures regarding the 

 State in which the caloric exists during its rapid 

 movement. It would be encroaching too much on 

 the time of the Society, to detail the whole of the 

 experiments which seem to prove this. I shall 

 therefore content myself with one which, of itself, 

 seems conclusive. 



Experiment 22, — When we put a piece of tinder 

 into a condensing syringe, and force down the pis- 

 ton, the tinder is inflamed ; from this fact I con- 

 cluded, that in the case of Colonel Yule's appara- 



YOL. III. k k 



