io6 Experiments to determine 



duced into the chamber, the cavity of the long tube was 

 filled up with cold tallow, and the screw that closed up 

 its end (which was \ an inch long, and but a little more 

 than y 1 ^- of an inch in diameter) was pressed down 

 against its leather collar with the utmost force. 



The manner of setting fire to the charge was as fol- 

 lows : a block of wrought iron about \\ inch square, 

 with a hole in it, capable of receiving nearly the whole 

 of that part of the short tube which projects beyond the 

 barrel, being heated red-hot, the end of the short tube 

 was introduced into this hole, where it was suffered to 

 remain till the heat, having penetrated the tube, set fire 

 to the powder it contained, and the inflammation was 

 from thence communicated to the powder in the chamber. 



The result of this experiment fully answered my ex- 

 pectations. The generated elastic fluid was so com- 

 pletely confined that no part of it could make its escape. 

 The report of the explosion was so very feeble as hardly 

 to be audible; indeed, it did not by any means deserve 

 the name of a report, and certainly could not have been 

 heard at the distance of twenty paces ; it resembled the 

 noise which is occasioned by the breaking of a very 

 small glass tube. 



I imagined at first that the powder had not all 

 taken fire, but the heat of the barrel soon convinced me 

 that the explosion must have taken place, and after 

 waiting near half an hour, upon loosening the screw 

 which closed the end of the long vent-tube, the confined 

 elastic vapours rushed out with considerable force, and 

 with a noise like that attending the discharge of an air- 

 gun. The quantity of powder made use of in the ex- 

 periment was indeed very small, not amounting to more 

 than \ part of what the chamber was capable of contain- 



