relating io ^/V and Water, 289 



of it with a burning lens tn vacuo, and thereby filled my 

 receiver with nothing but inflammable air. I had no fufpicioli 

 that tbe w^et leather on which my receiver ftood could have 

 any influence in the cafe, while the piece of charcoal was fub- 

 je6t to the intcnfe heat of the lens, and placed feveral inches 

 above the leatlier. I had alfo procured inflammable air from 

 charcoal in a glazed earthen retort two whole days fucceffively, 

 in which it had given inflammable air without Intermlflion. 

 Alfo iron filings in a gun-barrel, and a gun-barrel itfelf, had 

 always given inflammable air whenever I tried the experiment. 



Thefe circumflances, however, deceived me, and perhaps 

 would have deceived any other perfon ; for I did not know, 

 and could not have believed, the powerful attradion that char- 

 coal, or iron, appear to have for water when they are intenfely 

 hot. They will find, and attra£l it, in the mldfl: of the liotteft 

 fire, and through any pores that may be left open in a retort ; 

 and iron filings are feldom fo dry as not to have moifture 

 enough adhering to them, capable of enabling them to give a 

 confiderable quantity of inflammable air. But my attention 

 being now fully awake to the fubje6t, I prefently found that 

 the circumftances above-mentioned had adually mifled me; I 

 mean with refpeil to the conclujion which T drew from the expe- 

 riments, and not with refpe^t to the experiments themfelves, 

 every one of which, I doubt not, will be found to anfwer, 

 whenever they are tried by perfons of fufficient Ikill and pro- 

 perly attentive to all the circumflances. 



Being thus apprifed of the influence of unperceived moiflure 

 in the production of inflammable air, and willing toafcertain it 

 ta my perfeift fatisfaClion, I began with filling a gun-barrel with 

 iron filings in their common ftate, without taking any parti- 

 cular precaution to dry them, and I found that they gave, air as 



Vol. LXXV. P p they 



