262 GASES ABSORBED BY CHARCOAL. 



Charcoal alone fame effea. It is therefore in charcoal alone that this abforb- 

 abfoJbent°pro-" ®"^ property refides, and it is developed to the higheft degree 

 petty. by heat and light. 



Experiments on Ahnoffyheric Air. 

 Experiments on 13th, I then proceeded to examine the effecSls of incandef- 

 ^ ^ "^* cent charcoal on atmofpheric air, in my inftrument, and I re- 

 peated the experiments feveral times : the air of my garden 

 was conftantly lefs abforbed than that of ray bed-room, an hour 

 after the windows had been opened, and this was lefs abforbed 

 than that of my bed-room in the morning before opening the 

 windows : the abforptions were. 



The air of the garden, feven inches fix lines. 



The air of the room after the window had been open, eight 

 inches one line. 



The air of the room, in which it had not been renovated, 

 eight inches fix lines. 

 Former experi- 14th. In the experiments which I made in the year 1783, 

 °*^"^'» vvith tubes twelve inches in height, and one inch in diameter, 



I pafled the charcoal through the mercury ; the abforption of 

 the atmofpheric air was then always about three inches and 

 fix lines, that is to fay, a little more than one fourth ; in this 

 cafe it is uniformly greater and about one third. Probably the 

 mercury filled many of the interftices of the charcoal when it 

 was pafled through it, which might prevent this greater ab- 

 forption. 

 JUraf a privy. 1 5th. I afterwards examined the air of a privy, which was 

 taken into the fyringe feven toifes above the fewer. 



The abforption was eight inches, that is to fay, nearly equal 

 to that of my room. This did not furprize me, becaufe in 

 thofe compofitions which contain azote, this gas is not mnch 

 abforbed, as we (hall prefently fee : befides, Mr. White with 

 an eudiometer of nitrous gas alfo found that the air of a privy 

 gave him an abfoption equal to that of common air*. 



Experiments on the Gafes. 

 Experiments on \6ih. After having examined the atmofpheric air, I pro- 

 ceeded to the examination of carbonic acid gas ; I filled the 



• See Journal de Phyfique, Tom XVIII. p. 145, and the reflec- 

 tions of Guyton Morveau in his excellent treatife on the means of 

 difinfefting the aii*. 



tube 



