Gum, Sugary andanAcldy by means of Sulphuric Acid ^SSc. 5S 



the sulphuric acid. The mucilaginous mass thus diluted in wa- 

 ter was saturated with chalk, and, being filtered through a linen 

 cloth, became clear, and had only a very slight amber colour. 

 After washing the filter well, and pressing strongly the sulj)hate 

 of lime, I united the liquors together, and evaporated them to 

 the consistency of a syrup, which was less coloured than that of 

 capillaire. A small quantity of sulphate of lime was separated on 

 cooling, I continued the evaporation carefully until the mass 

 was quite dry, and I obtained a transparent gum, slightly co- 

 loured; it weighed 26*2 grammes (404-6 gr.) and was produced 

 from 21 -D grammes (332 gr.) of cloth, deducting the one gramme 

 of water, and the 2-5 grammes (38'6 gr.) of amylaceous ligneous 

 matter. I nmst not omit to mention that the sulphate of lime 

 resulting from the saturation, although well washed, still re- 

 tained vegetable matter ; for on being exposed to the fire it took 

 a brownish colour, and gave out an odour of sulphurous acid. 

 In order to ascertain whether this remarkable increase of weight 

 might not be owing to a fixation of the elements of water or sul- 

 phuric acid, five grammes (77'2 gr.) of this artificial gum were 

 dissolved in water ; I added to the solution some oxalic acid, in 

 order to precipitate the lime which it held in combination, and 

 which might also be precipitated from it by sulphuric acid. The 

 precipitate of oxalate of lime, collected andstrongly heated, gave 

 0*28 grammes (4 3 gr.) of lime. 



The gummy solution thus precipitated was evaporated to dry- 

 ness, and the residue treated with boiling nitric acid, and diluted 

 with water; some nitrate of barytes was added, which produced a 

 precipitate, that when heated red weighed 1-6 gramme (247 gr.) 

 which contained 0-54 gramihe (8'34gr.) of sulphuric acid. As 

 there was therefore no aeriform fluid disengaged during the ac- 

 tion of the sulphuric acid on the cloth, the 26-2 grammes 

 (404-6 gr.) of gummy matter which we obtained may be sup- 

 posed to be formed thus : 



Ligneous matter 21-50 gram. 



Elements of sulphuric acid fixed iu an un-^ o.nr, 

 known manner > I o6 



Elements of water fixed in an unknown man- 1 ^ ^a 

 ner | ^'^^ 



Lime combined 1-47 



Total .. 26-20 gram. 



It will be remarked that the manner in which wc have viewed 



the action of sulphuric acid concentrated on the cloth is very 



opposite to that of Messrs. Fourcroy and Vauquclin, since these 



chemists admit that the vegetable matter is decomposed, and di- 



D 4 vidcs 



