432 Dr. Priestley’s Experiments relating to Phlogtflon r 
time the water rofe within the receiver. This effect might be 
owing to a phlogiftica.tion of the air within the receiver; but 
it was loon diminilhed far beyond the utmoft limit of that pro- 
cefs, fo that very little of it remained ; and examining this air* 
I found it to be but very little worle than that of the atmo- 
lphere, as that which came from the retort was a little better. 
This experiment made it probable, that the air on the outfide 
of the receiver had actually palled through it, only a little pu- 
rified in its paliage ; and yet it was contrary to all the known 
principles of hydroftatics, and even any thing hitherto known 
in chemihry, that air Ihould be tranfmitted through a veflel of 
this kind, and in a direction contrary to that in which it would 
have been forced by the preflure of the atmofphere ; while the 
water, with which the clay was moiftened, went the other 
way. For had the retort been pervious to air, as the inlide 
had a free communication with the atmofphere, the water 
could not have rifen within the receiver. This, however, ap- 
peared to be the cafe by the following decifive experiments. 
Having filled the earthen retort with the moilfened clay as 
before, I made the inlide of the receiver perfectly dry, and 
placed it in a bafon of mercury ; when, upon heating the 
retort as before, the receiver was all covered with dew, w r hich 
collecting into drops trickled down the infide of the receiver* 
and remained upon the mercury, which rofe within the re- 
ceiver, w’hile air was received from the retort as ufual. I had 
no doubt, therefore, but that all the water within the retort 
would have got through into the receiver. Spirit of wine, or 
fomething that had the fmell of it, was tranfmitted from the 
clay through the retort in the fame manner. 
I then filled the receiver with inflammable air, and upon 
heating the retort it was all drawn through it, and delivered 
5 as 
