GASES ABSORBED BY CHARCOAL. 15 



34th. There might be reafon to believe that the charcoal, 

 by inflaming the oxigen gas, might convert it into carbonic 

 acid gas, which is the mod abforbed of all the gafes ; but to 

 faiisfy myfelf of this, I produced an abforption of oxigen gas 

 by a piece of charcoal, as in ,the former experiments : in 

 twenty-three hours it amounted to twelve inches, then with 

 a fyringe of cryfial I pafled fome lime-water through the mer- 

 cury into the remaining gas, and it did not become turbid, 

 which proves that carbonic acid was not formed ; and, having 

 turned up the tube, the refidual gas exlinguifhed a taper : I 

 believe it to have been azote. 



35 th. I was of opinion that incandefcent charcoal would 

 abforb more than another piece which had been fufFered to 

 cool till it no longer appeared red. Experiment (hews a 

 greater abforption in the firft for twenty-four hours; but, 

 leaving the apparatus undifturbed, in two days the abforption 

 became equal. I operated upon atmofpheric air. 



36th. I muff, acknowledge my inability to give an expla- 

 nation of thefe Angular experiments, as I have already de- 

 clared above : were I to hazard any conjectures, they would 

 probably be overturned by new theories, which do not fpare 

 even the labours of the greateft chemifts in France. 



37th. I fliall therefore continue my operations as I pro- 

 posed, and new experiments will, at leaft, fupply the want 

 of fyileras. 



On the Difference in the Charcoah made ufe of. 



38th. Having afcertained the abforptions effected by the Difference in the 



charcoal of beech wood in atmofpheric air and in the different c ^ arc ° a,s made 



... ufe of. 



gafes, I proceeded to examine the variations which the char- 

 coals of different woods would produce in them. 



39th. I therefore took two pieces of charcoal, the one of 

 beech, the other of the branches of fallow deprived of bark: Charcoal of fa! - 

 I introduced them both in an incandefcent ftate, and exa- low » 

 mined the difference of their abforption in the fame atmo- 

 fpheric air. 



That of beech gave an abforption of feven inches and eight 

 lines in fix hours. 



That of fallow gave only an abforption of four inches and 

 three lines, and there was no further abforption after fix 

 hours. 



Thefe 



