relating to Air and IVater, 28^ 



of it with a burning lens In vacm, and thereby filled my, 

 receiver with nothing but inflammable air. I kad no fufpicion 

 that the wet leather on which my receiver flood could have 

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

 je6l to the intenfe heat of the lens, and placed feveral inches 

 above the leather. I had alfo procured inflammable air from 

 charcoal in a glazed earthen retort two whole days fucceflively, 

 in which it had given inflammable air without intermifliou. 

 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 attraiflion that chm-- 

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

 hot. They will find, and attra£l it, in the midfl of the hottefl 

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

 and iron filings are feldom fb dry as not to have moiflure 

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

 conliderable quantity of inflammable air. But my attention 

 benig now fully awake to the fubjeifl, I prefently found that 

 the circumflances above-mentioned had adlually mifled me; I 

 mean with refpe£l to the conclitjion which T drew from the expe- 

 riments, and not with refpedt to the experiments themfelves, 

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

 whenever they are tried by perfons of fuf^cient fkill and pro- 

 perly attentive to all the circumflances. 



Being thus apprifed of the influence of unperceived moiflure 

 in the production of inflammable air, and wiUing toafcertain it 

 to my perfect fatisfadion, I began with filling a gun-barrel with 

 iron fihngs in their common flate, without taking any parti- 

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



Vol. LXXV. P p they 



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