l74 • HtSTORY OF pfxcOAL. 



Its resemblance Heat it with an acid at 20^, immediately a bulky efTer- 

 ▼ege e». ygg^jgn^.^ takes place. As the solution advai.ces, a deep yel- 

 low or amiotta coloured concretion forms. The ebullitioii 

 should be continued a little while, to collect all that can be 

 formed. This substance, which is sbft while the liquor iif 

 hot, is easily softened jmd separated. On washing it in 

 boihng water, this acquires a yellow colour, hut does not 

 dissolve it. When dry it is bulky, bitter, and soluble in 

 alcohol. But what is remarkable is its property of deto- 

 tiating obscurely with a very moderate heat like oxide of 

 charcoal, either iti a retort, or held over the ilame of a can- 

 dle on paper, 

 i^foclucts. Its products are water, a little oil, ammonia, carbonic 



acid gas, ^seous oxide of carbon buvninj^ with a blue Hame; 

 and '40 of a coal rridre bulky than the original substance. 



The liquor that remains after its separation is of a deep 

 yellow, and very bitter. It yields crystallized oxalic acidy 

 and benzoic acid. 

 Compared Pitcoal heated with an acid of 40° dissolves slowly, doe* 



^ith coal. not aiford any charcoal, and yields the detonating substance, 

 but with more difficulty, and in less quantity, than jetj 

 Cannel coal comports itself like common coal, and not like 

 jet. Some jet however does not yield the detonating sub^ 

 stance without an acid of 40^, 6r with as much difficulty as 

 pitcoal. 

 Hidrof»en not ^^ ^^ consider, that the first action of nitric acid on pit- 

 fiecessary to coal consists in destroying the hidrogen, we shdl easily con- 

 •lurco'al^ " ceive, that this hidvogen is not necessary to the formation or 

 the detonating substance. The following experiment evi- 

 dently shows this. Oxided yillanueva cpal, certainly con- 

 tains no hidrogen : yet, treated with an acid of 40°, it af- 

 fords the detonating substance ; and since this yields water, 

 ammonia, oil, &c., it is evident, that the nitroo:en, the oxi- 

 gen of the nitric acid, and the charcoal which the water is 

 capable of furnishing by the concurrence of affinities that 

 bring on its decomposition, establish theniselves in a fixed 

 Illustrates the proportion, to give rise to tliis singular product. A vegeto- 



formation of aj^inf^a] compound, an artificial oxide of this nature, remove* 

 tumun. ^ . . p . 



the difficulties I at first found in the formation of tannm 



from the simple presence of nitric acid and charcoal. 



Acid. 



