Mr. Faraday on the Liquefaction of Gases. 231 



glass tube, than any thing else to which it could be compared. In 

 many of the experiments, in which the elastic vapour Avas confined, 

 this feeble report attending the explosion of the powder, was im- 

 mediately followed by another noise totally different from it, which 

 appeared to be occasioned by the falling back of the weight upon 

 the end of the barrel, after it had been a little raised, but not suffi- 

 ciently to permit the leather stopper to be driven quite out of the 

 bore. In some of these experiments a very small part only of the 

 generated elastic fluid made its escape, in these cases the report 

 was of a peculiar kind, and though perfectly audible at some con- 

 siderable distance, yet not at all resembling the report of a mus- 

 ket. It was rather a very strong sudden hissing, than a clear dis- 

 tinct and sharp report." 



In another place it is said, " What was very remarkable in all 

 these experiments, in which the generated elastic vapour was 

 completely confined, was the small degree of expansive force which 

 this vapour appeared to possess, after it had been suffered to 

 remain a few minutes, or even only a few seconds, confined in the 

 barrel ; for upon raising the weight, by means of its lever, and 

 suffering this vapour to escape, instead of escaping with a loud 

 report it rushed out with a hissing noise, hardly so loud or so 

 sharp as the report of a common air-gun, and its effects against 

 the leather stopper, by which it assisted in raising the weight, 

 were so very feeble as not to be sensible." This the Count at- 

 tributes to the formation of a hard mass, like a stone, within the 

 cylinder, occasioned by the condensation of what was, at the 

 moment of ignition, an elastic fluid. Such a substance was always 

 found in these cases ; but when the explosion raised the weight and 

 blew out the stopper, nothing of this kind remained. 



The effects here described both of elastic force and its cessation 

 on cooling, may evidently be referred as much to carbonic acid 

 and perhaps other gases as to water. The strong sudden hiss- 

 ing observed as occurring when only a little of the products 

 escaped, may have been due to the passage of the gases into the 

 air, with comparatively but little water, the circumstances being 

 such as were not sufficient to confine the former, though they 



