C 112 3 



acetous and mucous acids, and empyreumatic oil, or 

 tar, and in some cases ammonia. The gasses are car- 

 bonic acid gas, carbonic oxide, and carburetted hydro- 

 gene ; sometimes with olefiant gas, and hydrogene ; 

 and sometimes, but more rarely, with azote. Car- 

 bonic acid is the only one of those gasses rapidly ab- 

 sorbed by water ; the rest are inflammable ; olefiant 

 gas burns with a bright white light ; carburetted hy- 

 drogene with a light like wax ; carbonic oxide with a 

 feeble, blue flame. The properties of hydrogene and 

 azote have been described in the last Lecture. The 

 specific gravity of carbonic acid gas, is to that of air 

 as 20.7 to 13.7, and it consists of one proportion of 

 carbon 11.4, and two of oxygene 30. The specific 

 gravity of gaseous oxide of carbon, is taking the same 

 standard 13.2, and it consists of one proportion of 

 carbon, and one of oxygene. 



The specific gravities of carburetted hydrogene and 

 olefiant gas are respectively 8 and 13 ; both 'contain 

 four proportions of hydrogene ; the first contains one 

 proportion, the second two proportions of carbon. 



If the weight of the carbonaceous residuum be 

 added to the weight of the fluids condensed in the 

 receiver and they be subtracted from the whole weight 

 of the substance, the remainder will be the weight of 

 the gaseous matter. 



The acetous and mucous acids, and the ammonia 

 formed are usually in very small quantitities ; and by 

 comparing the proportions of water and charcoal with 

 the quantity of the gasses, taking into account their 

 qualities, a general idea may be formed of the compo- 

 sition of the substance. The proportions of the ele- 



