454 COMPOUND PRODUCTS. CHAP. I, 



or frothing, and exhales a thick smoke and pungent 

 odour, leaving a charcoal that retains the form of 

 the original mass. When distilled in a retort it 

 yields an empyreumatic oil, carburetted hydrogene 

 gas, carbonic acid, and a portion of ammonia, ac- 

 cording to Fourcroy, indicating the presence of 

 nitrogene as constituting one of its elementary prin- 

 ciples, and yet this ingredient does not appear in 

 the result of the later analysis of Messrs. Gay 

 Lussac and Thenard, which is as follows from ex- 

 periments on the wood of the Oak : 



Composi- Carbon 52-53 



tion. 



Oxygene 4178 



Hydrogene. . 5*69 



Total 100- 



SECTION XXII. 



Charcoal. 



How pn* WHEN wood is burnt with a smothered flame, the 

 volatile parts are driven off by the heat, and there 

 remains behind a substance exhibiting the exact 

 form, and even the several layers of the original 

 mass. This process is denominated charring, and 

 the substance obtained, Charcoal. As it is the 

 woody fibre alone which resists the action of heat, 



