)0 Experiments on Charcoal, 



direct experiment, fince the gafes cannot be obtained perfectly 

 dry. 



From analogy we were inclined to think, that if the gafes 

 abiblulely contained the fame quantity of water, they ought 

 alfo to contain equal quantities of the liquids which are vola- 

 tilized by their contact., fitch as alcohol and ether. 



The action of the elallic fluids on the latter being very 

 great, it was eafy to form an exact opinion of it. We there- 

 tore made experiments, from which it refults, that, tempera- 

 ture, pretfure, and other circumftances, being the fame, all 

 the gafes of which we have here fpoken, hydrogen as well as 

 the carbonic acid, equally favour the evaporation of ether ; 

 that is to fay, that in equal fpaces occupied by any gas what- 

 ever, the fame quantity of this liquid may be there reduced to 

 the elaftic (late, and product the fame expanfion. The cafe is 

 the fame with alcohol, but the quantity evaporated is much 

 lefs than that of ether *> 



The nature of the gas, then, has no influence on the pro- 

 perty which they have of vaporizing ether and alcohol, as it 

 depends only on the temperature and preflure. It is probable 

 that the cafe is the fame with the evaporation of water. If 

 it were poffible, indeed, to exercife on the ethereal or alco- 

 holized gafes an action fimilar to that of the muriate of lime 

 on humid gafes; that is to fay, if the ether or alcohol could 

 be taken away by fimilar means, they might be equally de- 

 prived of it; but, as we took from the gafes the fame quan- 

 tity of water, there ie great reafon to prefume that it is abso- 

 lutely the fame. 



This being the cafe, it appears to us that if well made char- 

 coal, not moift, be burned with dried oxygen, and if the gas 

 produced by the combuflion mould not contain more water 

 than what the abforbing fait had left in the oxygen before 

 its being employed ; that is to fay, if it mould pafs upon a 

 fimilar quantity of fait without augmenting its weight, we 

 ihould be almoft certain that the combuition of charcoal 

 would produce no water : we therefore made the following 

 experiment : 



Into a very long glafs tube placed upon a fmall furnace we 

 introduced 4*50 grammes of charcoal of common wood 

 heated in a furnace for an hour, and not yet cooled. To 

 the extremities of the tube we adjufted two others containing 

 the fame quantity of muriate of lime : the latter were im- 



* The interefting phenomena exhibited by the action of gales on the 

 Jiquids induced us to make experiments, which we mail give an account 

 et in another memoir. 



nierfecj 



