^64- Combii/lhn cf GuiipcivJer in a Clofed I'<Jil; — :'// Refuhit. 



hammered brafs, and upon this brafs plate the flat furface of the hemifphere. When 

 the eladic fluid made its efcape, a part of the leather was conftantly found to have been 

 torn away, but never in more places than one ; that is to fay, always on one fide only. 



What was very remarkable, in all thofe experiments in which the generated eladic va- 

 pour was completely confined, was the fniall degree of expanfive force which this vapour 

 appeared to pofl'efs after it had been furthered to remain a few minutes, or even only a few 

 feconds, confined in the barrel ; for upon ralfing the weight by means of its lever, and fuf- 

 fering this vapour to efcape, inftead of efcaping with a loud report, it rulhed out with a 

 hiCing noife, hardly fo loud or fo fharp as the report of a common air-gun ; and its cITeifls 

 againft the leathern (lopper, by which it alTifted in railing the weight, were fo very feeble as 

 not to be fenfible. Upon examining the barrel, however, this diminution of the force of the 

 generated clallic fluid was eafily explained ; for what the Count thinks was undoubtedly in 

 the moment of tfie explofipn in the form of an eladic fluid, was now found transformed into a 

 foKd body as hard as a done. It may eafily be imagined how much this unexpcfted appear- 

 ance excited his curiofity ; but, intent on the profecution of the main defign of thefe experi- 

 ments, the afcertaining the force of fired gun-powder, he was determined not to permit him- 

 felf to be enticed away from it by any extraordinary or unexpefted appearances or accidental 

 difcoveries, however alluring they might be ; and faithful to this refolution, he podponed the 

 examination of this curious phenomenon to a future period, and fincc that time he has not 

 found leifure to engage in it. He thinks it right, however, to mention fuch curfory obfer- 

 vations as he was able in the midd of his other purfuits to make upon this fubjecl. 



This matter was very Iiard, and fo firmly attached to the infide of the barrel, and parti- 

 cularly to the infide of the upper part of the vent tube, tliat it was always neceflary, in order 

 to remove it, to make ufe of a drill, and frequently to apply a confiderable degree of force. 

 It was of a black colour, or rather of a dirty grey, which changed to black upon being ex- 

 pofed to the air, had a pungent acrid alkaline tade, and fmelt like liver of fulphur. It at- 

 trafted moidure from the air with great avidity. Being moidened with water, and fpirit 

 of nitre bein'T poured upon it, a drong effervefcence enfued, attended with a very ofl^enfivc 

 and penetrating fmell. Nearly the whole quantity of matter of which the powder was 

 ■compofed feemed to have been transformed into this fubdance * ; for the quantity of eladic 

 fluid which efcaped upon removing the weight was very inconfiderable. But this fubdance 

 was no longer gun-powder ; it was not even inflammable. 



What change had it undergone ? demands our author, — What could it have lod .' It is 

 very certain the barrel was confiderably heated in thefe experiments. Was this occafioned 

 by the caloric, difengaged from the powder in its combudion, making its efcape through the 

 iron .' And is this a proof of the exidence of caloric confidered as a fluid y;« generis ; and 

 that it aflually enters into the compofition of inflammable bodies, or of pure air, and is ne- 

 ceflary to their combudion ? He dares not take upon him to decide upon fuch important 

 quedions. He once thought that the heat acquired by a piece of ordnance in being fired 

 arofc-from the vibration or fridlion of its parts, occafioned by the violent blow it received la 



* It is much to bi regretted that no experimcot was made of the weight of this fubflancc tSuuiti by a 

 given weight of gunpowder. N. 



th£ 



