Intelligence and Miscellaneous Articles. 997 



PREPARATION AND COMPOSITION OF LIGNIN. 



MM. Poumarede and Figuer state as a test of the purity of lignin, 

 that when immersed in concentrated sulphuric acid it is not ren- 

 dered black. In order to procure it in this state, a piece of wood 

 is to be transversely rasped, and the raspings are to be immersed in 

 soap ley for twenty-four hours ; the mixture is then to be diluted 

 with once or twice its weight of water and poured off; the insoluble 

 residue is to be largely washed with water, treated with a slight ex- 

 cess of dilute hydrochloric acid, and again washed with water. After 

 this the ligneous fibre is to be treated with great excess of a solution 

 of common salt ; the digestion is to be continued with occasional 

 stirring for two or three days, a fresh portion of the solution being 

 once used ; this being poured off, the fibrous matter is to be treated 

 with a weak alkaline solution till it comes away colourless ; it is to 

 be again washed, and the remaining alkali is to be saturated by slight 

 excess of hydrochloric acid, and after again washing with distilled 

 water till litmus is not reddened, the product, placed on a sieve, is 

 to be dried either in the sun or a stove. 



The lignin thus obtained, after being washed with alcohol and 

 aether, is not coloured by concentrated sulphuric acid, and is to be 

 considered as absolutely pure. It is white and silky, and possesses 

 the organic structure of the wood from which it has been obtained ; 

 and the authors consider themselves authorized to conclude that in 

 analysing this substance, they operate on the vegetable skeleton such 

 as it exists in plants. 



The authors find that the results of their analyses differ but very 

 little from those obtained by M. Payen ; they nevertheless deem it 

 necessary to state them as satisfactorily proving the agreement which 

 exists between the various kinds of lignin of very ditterent origin. 



Lignin of the poplar, dried at 288° F. ; mean of three experi- 

 ments : — 



Carbon 43-88 



Hydrogen 6'23 



Oxygen 49*89 



100-00 



Lignin of the beech, dried at 288° F. : — 



Carbon ...i >••>>.. . 43-85 



Hydrogen 6*22 



Oxygen 49-93 



100-00 



Blotting-paper treated with acids, alkalies, water, und alcohol, 

 dried at 288° F. :— 



I. XL 



Carbon 43-87 43*84 



Hydrogen 6-12 6*22 



Oxygen 50-01 49*94 



100-00 100-00 



