the Force of Fired Gunpowder, 



135 



diameters were gradually diminished toward the middle 

 of their lengths, where their measures were taken, and 

 where they never failed to break. 



As I had found by the results of many experiments, 

 which I had before made upon the strength of the 

 various metals, that iron, as well as all other metals, is 

 rendered much stronger by hammering, I caused those 

 pieces of the barrel which were prepared for these ex- 

 periments to be separated from the solid block of metal, 

 and reduced to their proper sizes, by sawing, filing, and 

 turning, and without ever receiving a single blow of a 

 hammer ; so that there is every reason to believe that the 

 strength of the iron, as determined by the experiments, 

 may safely be depended on. The results of the experi- 

 ments were as follows : — 



If now we take the strength of the iron of which the 

 barrel was composed, as here determined by actual ex- 

 periments, and compute the force required to burst the 

 barrel, it will be found equal to the pressure of a weight 

 of 410,624!- lbs. instead of 436,800 lbs. as before deter- 

 mined. For it is the resistance or force of cohesion of 

 I inch of this iron to 63,173 lbs., as that of 6|- inches 

 (the area of the fracture of the barrel) to 410,62,4-1- lbs. 



