120 Memoir upon the Conversion of ligneous Bodies into 



dried, were reduced into mucilage by 34 j2;ramines (525 gr.) of 

 sulphuric acid, observing the precautions before indicated ; the 

 acid mixture, dissolved in a certain quantity of water, precipitated 

 the ligneous matter a little altered ; when dried it weisrhcd 36 

 grammes (55-5 gr.) The acid li(|Uor thus diluted with water, 

 was boiled about ten hours; after which it was saturated with 

 carbonate of lime. This liquor did not precipitate the sub- 

 acttate of lead ; it no longer contained any giun ; the residue 

 was evaporated and dried as much as possible until it beaj^jn to 

 exhale an odour of calomel. In this state it weighed 23*3 gram. 

 (359'8 gr.) which were furnished by 20 4 grammes (315 jjr.) of 

 cloth, deduction being made of what was not reduced : but I 

 believe that there were some losses ; for the sulphate of lime, al- 

 though well washed, had a slight coloured teint, different from 

 what results from the preparation of artificial gum : however, like 

 the latter, in place of burning in the fire and disengaging sidphu- 

 ric acid, it became whiter, and did not exhale any very particular 

 odour. I made these 23"3 grammes (359'8 gr.) of sugary mat- 

 ter into the consistence of syrup*; at the end of 24 hours it 

 began to crystallize ; and some days after, the whole was solidi- 

 fied into a single mass of crystallized sugar, which was pressed 

 strongly between several folds of old cloth ; crystallized a second 

 time this sugar was passably pure ; but treated with animal char- 

 coal it became of a shining whiteness. The crystals were in 

 spherical groupes, which appear to be formed by the union of 

 &mall diverging and unequal plates. They are fusible at the 

 temperature of boiling water. This sugar, of a fresh and agree- 

 able flavour,produced in the mouth a slight sensation of coolness. 

 It dissolves in hot alcohol, and crystallizes by cooling. Dissolved 

 in water and mixed with a little yeast, it fermented ; the vinous 

 liquor which resulted furnished alcohol by distillation. Burnt 

 with potash, and its charcoal washed with diluted nitric acid, it 

 yielded a fluid not troubled by nitrate of barytes. It would be 

 useless to insist further on the properties of this sugar ; it is evi- 

 dent that it is perfectly identical with the sugar of grapes^ or of 

 starch. 



The conversion of wood into sugar will no doubt appear re- 

 markable; and,wl en persons not familiarised with chemical spe- 



• This syrup was weakly affected by sulphuric acid, while a concentrated 

 solution of gum obtained by saturation with chalk was sensibly precipitated 

 by the same acid which separated it from the sulphate of lime ; from which 

 there seems reason to presume that in converting this gum into sugar, by 

 boiling it a long time with weak sulphuric acid, the elements of that acid 

 ■which itcontainsdo not entirely reunite to form the vegeto-sulphuric acid; but 

 that a part separates from it in the state of free sulphuric acid,%nd the rest 

 continues mingled with thdt which serves to effect the saccharification, 



culations 



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