132 Experiments to determine 



sidered, and the smallness of the capacity of its bore, it 

 appears almost incredible, that so small a quantity of 

 powder as that which was employed in the experiment 

 could burst it asunder. 



But without insisting on the testimony of several 

 persons of respectable character, who were eye witnesses 

 of the fact, and from whom Sir Charles Blagden received 

 a verbal account, in detail, of all the circumstances at- 

 tending the experiment, I fancy I may very safely rest 

 my reputation upon the silent testimony which this 

 broken instrument will bear in my favour; much doubt- 

 ing whether it be in the power of art to burst asunder 

 such a mass of solid iron by any other means than 

 those I employed. 



Before I proceed to give an account of my subsequent 

 experiments upon this subject, I shall stop here, for a 

 moment, to make an estimate — from the known 

 strength of iron^ and the area of the fracture of the bar- 

 rel — of the real force employed by the elastic vapour 

 to burst it. 



In a course of experiments upon the strength of 

 various bodies, which I began many years ago, and an 

 account of which I intend at some future period to lay 

 before the Public,* I found, by taking the mean of the 

 results of several experiments, that a cylinder of good 



* Since writing the above, I have met with a misfortune which has put it out of 

 my power to fulfil this promise. On my return to England from Germany in October, 

 1795, after an absence of eleven years, I was stopped in my post-chaise, in St. Paul's 

 church-yard, in London, at six o'clock in the evening, and robbed of a trunk which 

 was behind my carriage, containing all my private papers, and my original notes and 

 observations on philosophical subjects. By this cruel robbery I have been deprived of 

 the fruits of the labours of my whole life ; and have lost all that I held most 

 valuable. This most severe blow has left an impression on my mind, which I feel 

 that nothing will ever be able entirely to remove. 



It is the more painful to me, as it has clouded my mind with suspicions that never 

 can be cleared up. 



