838 COMPOUNDS CONTAINED IN WOOD TAR. 



g * 



a hydrocarbon, and contains no oxygen. It does not mix with 

 sulphuric acid, but by long digestion and agitation, it disappears 

 entirely, and is partly converted into a black resin, C 24 H 16 O, 

 which is insoluble in alcohol and wood-spirit, but soluble in 

 ether and xylite. Methol is not converted into this resin by 

 the action of air. The acid solution neutralised with carbonate 

 of lime gives a white crystalline salt, containing met hoi-sulphuric 

 acid, of which the formula when free is HO,SO 3 -f C 12 H 9 , SO 3 , 

 or perhaps rather HO, C 12 H 8 S 2 O 5 + HO * 



Mr. Scanlan has shown that crude wood-spirit contains free 

 aldehyde, which he has extracted from it in a state of purity by 

 submitting the crude spirit to successive distillations. L. Gme- 

 lin obtained acetone from the wood- spirit of the French manu- 

 factories ; it distilled over first when the crude spirit was recti- 

 fied from chloride of calcium. 



Pyroxanthin, eblanin^ C 21 H 9 O 4 (Gregory and Apjohn) ; a 

 crystalline substance of an orange colour, obtained by Mr. Scan- 

 Ian on distilling crude pyroxylic spirit from slaked lime. It 

 remains with the lime, and after neutralising the latter with 

 acetic acid, may be taken up by alcohol, from which it is 

 deposited in long needles or prisms having the colour of car- 

 bazotate of potash. It is insoluble in water and in alkalies, but 

 soluble in alcohol, ether and concentrated acetic acid. It sub- 

 limes at 273 , but does not melt till it is raised to the tem- 

 perature of 291. Concentrated sulphuric acid dissolves it. 

 and assumes a red blue colour. J 



SECTION IV. 



OTHER PRODUCTS OF THE DISTILLATION OF WOOD, CONTAINED 



IN TAR. 



Paraffin is a particular hydrocarbon, produced in the distilla- 

 tion of wood, and in many other circumstances, which has the 

 same composition per cent as olefiant gas, or CH. It is a crys- 



* F. Weidmann and E. Schweizer ; Poggendorff's Annalen, xliii, 593 ; xlix, 

 135 and 293; 1,265. 



t From Eblana, Dublin. 



t Liebig's Annalen for 1837 ; or Dr. Thomson's Organic Chemistry, Vege- 

 tables, p. 750. 



