17S ttlSTORV OF PtTCOAL. 



in it all except 15 grains, perhaps either because ihey were 

 not oxided, or because the oxigen had accumulated in the 

 rest, to facilitate its solution. From this solutiou an acid 

 threw down a precipitate, which was black and shining when 

 dry. It did not nnielt, and exhaled no smell on burning 

 coals. 



Oxigenized muriatic acid precipitated it, without acting 

 on the precipitate. 

 Tlie solution, TJiis same charcoal, oxided, dissolved, and precipitated, 

 ySed sUe^< ^^'^ ^^^"^ burnt gray ashes, a little ferruginous, in which I 

 alamine, and found, silex, alumine, and a httle oxide. What sort of 

 *'^' union is there then between charcoals and their ashes? We 



should suppose potash could not dissolve the latter. 1 ap- 

 plied nitric acid to difft^rent sorts of charcoal, to divest thera 

 of ashes, and try whether they would burn away entirely ; 

 but I could not succet^d. 



I had intended to pursue the inquiry farther, but have 



What so t of t>een prevented. TMeantime it will naturally be asked, what 



combuiativ^n is (.Qj^Vj^f^^^^Qj^ qP Qjj^™gj^ ^j^jj charcoal is this, that excludes 



neither nitrogen, nor any of the foreign substances it usually 



contains ? and again what kind of union can charcoal form 



with the same principle, without losing any thing of its den»- 



eity or colour, which appears so little conformable to the 



lavvd of combination ? I can only say, I know nothing on 



the subject. 



We Icnow less I would likewise ask, what is the nature of the combina- 



c^ charcoal tiou that charcoal enters into with hidroo-en and nitrogen, 

 tflanoi carbon. . . ^ . 



and other gasses which it absorbs and condenses in such 



large quantity? In fact we are far from being as well acr 



quainted with charcoal, which we see daily, as with carboq, 



which never comes under tUe cognizance of our senses. 



Duhidrogenized coal. 



Coal divested When we consider how much the proportion of coak 

 of hidrogen. varies m pitcoals, we shall find it difficult not to believe, that, 

 if these bitumens be really derived from plants like ours, the 

 concentration of the carbonaceous principle, which is nothing 

 but the loss of hidrogen, must h;ive varied considerably in 

 different countries, A coal that yields '77 of coak cannot 



contain 



