15<« PHILOSOPHICAL TRANSACTIONS. [ANNO 1797- 



barrel. On removing the barrel and examining it, its bore was found to be 

 choaked up by the solid substance already described, and from which it was with 

 some difficulty that it was freed, and rendered fit for another experiment. The 

 extreme feebleness of the report of the explosion, and the small degree of force 

 with which the generated elastic fluid rushed out of the barrel on removing the 

 weight which had confined it, had inspired my assistants with no very favourable 

 idea of the importance of these experiments. I had seen, indeed from the begin- 

 ning, by their looks, that they thought the precautions T took to confine so incon- 

 siderable a quantity of gunpowder as the barrel could contain, perfectly ridiculous ; 

 but the result of the following experiment taught them more respect for an agent, 

 of whose real force they had conceived so very inadequate an idea. 



In this 2d experiment, instead of 10 grains of powder, as in the former charge, 

 the barrel was now quite filled with powder, and the steel hemisphere, with its oiled 

 leather under it, was pressed down on the end of the barrel by the same weight as 

 was employed for that purpose in the first experiment, viz. a cannon weighing 

 8081 lbs. In order to give a more perfect idea of the result of this important ex- 

 periment, it may not be amiss to describe more particularly one of the principal 

 parts of the apparatus employed in it, I mean the barrel. This barrel, which 

 though similar to it in all respects, was not the same that has already been de- 

 scribed, was made of the best hammered iron, and was of uncommon strength. Its 

 length was 2^- inches ; and though its diameter was also 24 inches, the diameter of 

 its bore was no more than 4. of an inch, or less than the diameter of a common 

 goose quill. The length of its bore was 2.15 inches. Its diameter being 2-f- inches, 

 and the diameter of its bore only 4- of an inch, the thickness of the metal was l-f 

 inch ; or, it was 5 times as thick as the diameter of its bore. The charge of powder 

 was extremely small, amounting to but little more than -^ of a cubic inch ; not so 

 much as would be required to load a small pocket pistol, and not -JL- part of the 

 quantity frequently used for the charge of a common musket. I should be afraid 

 to relate the result of this experiment, had I not the most indisputable evidence to 

 produce in support of the facts. This inconsiderable quantity of gunpowder, when 

 it was set on fire by the application of the red-hot ball to the vent-tube, exploded 

 with such inconceivable force as to burst the barrel asunder in which it was con- 

 fined, notwithstanding its enormous strength ; and with such a loud report as to 

 alarm the whole neighbourhood. It is impossible to describe the surprise of the 

 spectators of this phenomenon. They literally turned pale with affright and 

 astonishment, and it was some time before they could recover themselves. The 

 barrel was not only completely burst asunder, but the 2 halves of it were thrown 

 on the ground in different directions : one of them fell close by my feet, as I was 

 standing near the machinery to observe more accurately the result of the experi- 

 ment. Though I thought it possible that the weight might be raised, and that the 

 generated elastic vapour would make its escape, yet the bursting of the barrel was 



