Ke/idiie ofGunpoluihf bunted in a clofe Vejel. ^6< 



the eicplofion of the powder, but acknowledges fairly that it does not feem to be polTible ta 

 account in a fatisfaftory manner for the very confiderable degree of heat which the barrel 

 acquired in thefe experiments, merely on that fuppofition. 



That this hard fubftance found in the barrel, after an experiment in which the generated 

 elaftic vapour had been completely confined, was a£lually in a fluid or elaflic (late in the 

 moment of the exploGon, is evident, as he thinks, from hence: that in all thofe cafes in which 

 the weight was raifed, and the ftopper blown out of the bore, nothing was found remaining 

 in the barrel. It was very remarkable, that this hard fubftance was not found diftributed 

 about in all parts of the barrel indifferently, but there was always found to be more of it near 

 the middle of the length of the bore than at either of its extremities, and the upper part of 

 the vent tube in particular was always found quite filled with it. It ihould feem therefore, 

 fays he, that it attached itfelf to thofe parts of the barrel which were fooneft cooled ; and 

 hence the reafon, moft probably, why none of it was ever found in the lower part of the vent- 

 tube, where it was kept hot by the red-hot ball by which the powder was fet on fire. 



He found by a particular experiment, that the gunpowder made ufe of, when it was well 

 fliaken together, occupied rather lefs fpace in any given meafure than the fame weight of wa- 

 ter; confequently when gunpowder is fired in a confined fpace which it fills, the denfityof 

 the generated elaftic fluid muft be at leaft equal to the denfity of water. The real fpecific 

 gravity of the folid grains of gunpowder, determined by weighing them in air and water, Is 

 to the fpecific gravity of water as i,868 to loco. But if a meafure whofe capacity is one 

 cubic foot hold looo ounces of water, the fame meafure will hold juft 1077 ounces of fine- 

 grained gunpowder, fuch as was ufed in thefe experiments, that is to fay, when it is well 

 (haken together. When it was moderately (haken, together its weight was exadtly equal to 

 that of an equal volume, or rather meafure, of water. But it is evident that the weight of any 

 given meafure of gunpowder muft depend much upon the forms and fizes of its grains." 

 He adds one obfervation more relative to the particular appearances which attended the ei- 

 perimcnts, in which the elaftic vapour, generated in the combuftion of gunpowder, was con- 

 fined, and that is with regard to a curious effcd produced upon the inferior flat furface of 

 the leathern ftopper where it was in conta£l with the generated elaftic vapour. Upon re- 

 moving the ftopper, its lower flat furface appeared entirely covered with an extremely white 

 powder, refembling very light white afties, but which almoft inftantaneoufly changed to the 

 moft perfe£l black colour upon being expofed to the air. 



The fudden change of colour in this fubftance, upon its being expofed to the air, led him 

 to fufpe£t that the folid matter found in the barrel was not originally black, but that it be- 

 came black merely in confequence of its being expofed to the air. The dirty grey colour it 

 appeared to have, immediately on being drilled out of the cavity of the bore where it had 

 fixed itfelf, feems to confirm this fufpicion. An experiment made with a very ftrong glafs 

 barrel would not only decide this queftion, but would moft probably render the experiment 

 peculiarly beautiful and interefting on other accounts. 



The Count thinks a barrel of glafs might be made ftrong enough for the experiment, if it 

 could withftand the fudden heat, and on the whole fcems difpofed to think the trial worth 

 making. 



All the parts of the operation being ready, it was in the autumn of the year 1792 that 

 the firft experiment was made. 



Vol. I.— January 17(^8. 3O Tht 



