314 
periment, the carbonic gas entirely disappeared, but 
what became of it Mr Dalton does not state ; he 
denies, however, its attraction by the charcoal, and 
asserts that the increase of weight, which that sub- 
stance received, proceeded entirely from the moisture 
of the bladder. He considers the attraction of mois- 
ture to be the only cause of the increase of weight, 
which newly-made charcoal receives ; and to the de- 
composition of this moisture, and the union of its 
elements with charcoal, he ascribes the abundance of 
gases obtained from charcoal at a red heat. Mr 
Dalton adds, that the expulsion of gases from char- 
coal by the heat of boiling water, as alleged in these 
experiments, is certainly not true, as Allen and 
Pepys have shewn ; and most practical chemists 
know, says he, that no air is to be obtained from 
moist charcoal below a red heat *. 
613. Notwithstanding the confidence with which 
Mr Dalton delivers himself on this subject, we shall 
proceed to point out a few circumstances in his experi- 
ment, which prevent our acquiescence in his con- 
clusions. As he seems to have relied chiefly on the 
circumstance of weight, for determining the alleged 
attraction of these gases, it might have been expect- 
ed, that, like his predecessors, he would have em- 
ployed an apparatus which could not have commu- 
nicated moisture to the charcoal, instead of the blad- 
der which he actually used, and which, he says, did 
comarumicate moisture. But the circumstance of 
increased weight does not afford such satisfactory 
* Chem. Phil, part ii. p. 235. 
