ioo . Experiments , to determine 



peared that, calculating even upon Mr. Robins's own 

 principles, the force of gunpowder, instead of being 

 1000 times, must ar?least be 1308 times greater than the 

 mean pressure of the atmosphere. However, not only 

 that experiment, but many others, mentioned in the 

 same paper, had given me abundant reason to conclude 

 that the principles assumed by Mr. Robins, in his 

 treatise upon gunnery, were erroneous, and I saw no 

 possibility of ever being able to determine the initial 

 force of gunpowder by the methods he had proposed, 

 and which I had till then followed in my experiments. 

 Unwilling to abandon a pursuit which had already cost 

 me much pains, I came to a resolution to strike out a 

 new road, and to endeavour to ascertain the force of 

 gunpowder by actual measurement, in a direct and de- 

 cisive experiment. 



I shall not here give a detail of the numerous diffi- 

 culties and disappointments I met with in the course of 

 these dangerous pursuits ; it will be sufficient briefly to 

 mention the plan of operations I formed, in order to 

 obtain the end I proposed, and to give a cursory view 

 of the train of unsuccessful experiments by which I was 

 at length led to the discovery of the truly astonishing 

 force of gunpowder, a force at least fifty thousand 

 times greater than the mean pressure of the atmosphere ! 



My first attempts were to fire gunpowder in a con- 

 fined space, thinking, that when I had accomplished this, 

 I should find means, without much difficulty, to measure 

 its elastic force. To this end, I caused a short gun-bar- 

 rel to be made, of the best wrought iron, and of uncom- 

 mon strength ; the diameter of its bore was -| of an 

 inch, its length 5 inches, and the thickness of the metal 

 was equal to the diameter of the bore, so that its ex- 



