DISCHARGING OF ORDNANCE. 479 



10, Super-oxymuriate of potassa, - 3.0 

 Dried gunpowder, - 21.0 



This is the best. 



11. Super-oxymuriate of potassa, - 1.0 

 Gunpowder in fine powder, - 1.0 



This is the second best. 



After numerous trials with these, their compara- 

 tive regularity in producing the desired effect was 

 calculated to be nearly as has been noted in the 

 above list ; but I found that even No. 10. was not 

 so uniform as was necessary for Colonel Yule's ob- 

 ject. I had now, however, almost doubted of success, 

 when it occurred to me to try the composition 

 which has since been found to succeed for more than 

 an hundred successive times, without leaving any 

 residuum to stop the firing. Of the composition of 

 this powder, and some cautions necessary to be at- 

 tended to in its preparation, an account will be 

 given in a future paper. 



It was with this powder that I performed the ex- 

 periments which presented those striking results, of 

 which I have now to give a brief account. 



I was led to these, with the hope of elucidating, 

 still farther than I had previously done, a particu- 

 lar view of caloric, of which I have, for six years 

 past, given an account in my chemical classes. I 

 availed myself of the use of Colonel Yule's appa- 

 ratus, to commence the investigation ; and I am 

 still occupied with it. At present, therefore, it is 



