158 PHILOSOPHICAL TRANSACTIONS. [ANNO 1797. 



If now we take the strength of the iron of which the barrel was composed as 

 here determined by actual experiments, and compute the force required to burst 

 the barrel, it will be found equal to the pressure of a weight of 4100244- lbs. in- 

 stead of 4 1 2529 as before determined. For it is the resistance or force of cohe- 

 sion of 1 inch of this iron to 63173 lbs., as that of 64- inches, the area of the 

 fracture of the barrel, to 4 106244- lbs. And this weight turned into atmospheres, 

 in the manner above described, gives 54750 atmospheres for the measure of the 

 force which must have been exerted by the elastic fluid in bursting the barrel. But 

 this force, enormous as it may appear, must still fall short of the real initial force 

 of the elastic fluid generated in the combustion of gunpowder, before it has begun 

 to expand ; for it is more than probable that the barrel was in fact burst before the 

 generated elastic fluid had exerted all its force, or that this fluid would have been 

 able to have burst a barrel still stronger than that used in the experiment. — But I 

 wave these speculations in order to hasten to more interesting and more satisfac- 

 tory investigations. Passing over in silence a considerable number of promiscuous 

 experiments, which, having nothing particularly remarkable in their results, could 

 throw no new light on the subject, I shall proceed immediately to give an account 

 of a regular set of experiments, undertaken with a view to the discovery of certain 

 determined facts, and prosecuted with unremitting perseverance. 



These experiments were made by my directions under the immediate care of 

 Mr. Reichenbach, commandant of the corps of artificers in the Elector's mili- 

 tary service, and of Count Spreti, first lieutenant in the regiment of ar- 

 tillery. Though I was prevented by ill health from being actually present at all 

 these experiments, yet being at hand, and having every day, and almost every 

 hour, regular reports of the progress that was made in them, and of every thing 

 extraordinary that happened, the experiments may be said with great truth to have 

 been made under my immediate direction ; and as the two gentlemen by whom I 

 was assisted, were not only every way qualified for such an undertaking, but had 

 been present, and had assisted me in a number of similar experiments which I had 

 myself made, they had acquired all that readiness and dexterity in the various ma- 

 nipulations which are so useful and necessary in experimental inquiries ; and I think 

 I can safely venture to say that the experiments may be depended on. If would 

 have afforded me great satisfaction to have been able to say that the experiments 

 were all made by myself; and I had resolved to repeat them before I made them 

 public, particularly as there appear to have been some very extraordinary and quite 

 unaccountable differences in the results of those made in different seasons of the 

 year ; but having hitherto been prevented by ill health, and by other avocations, 

 from engaging again in these laborious researches, I have thought it right not to 

 delay any longer the publication of facts, which appear to me to be both new and 

 interesting, as their publication may perhaps excite others to engage in their fur- 

 ther investigation. 



