126 On ike Conversion of ligneous Bodies into Gum, Sugar, &c. 



cipitates. This compound imparts a yellow colour to to linen, 

 silk, and cotton. 



The same artificial substance is soluble in concentrated sul- 

 phuric acid, like ligneous bodies ; but it is abundantly precipi- 

 tated by water. 



It is very easily dissolved in alcohol, and yields a deep brown 

 liquor which is precipitated hy water. It this solution is allowed 

 to evaporate spontaneously, it forms at its surface pellicles which 

 have a crystalline contexture ; but if the evaporation is forced 

 more rapidly, a black shining residuum is obtained which resem- 

 bles resin. Exposed to the flame of a lamp, it swells, and burns 

 with a shght flame. Twenty grammes (3 18' 10 gr.) of artificial 

 ulmine from old linen were distilled in a glass retort; a litjuid 

 product was obtained from it of the weight of seven grammes : 

 consistingof fourgrammesof a colourless fluid, and three grammes 

 of oil,enipyreuinatic, brown, fluid, and soluble in any proportion 

 in alcohol in an alkaline ley. 



The colourless liquid contains nothing but acetic acid, and 

 some traces of oily matter. There remains a charcoal of the ap- 

 pearance of bronze of the weight of 9-8 grammes, which left 

 after its combu-stion 0'75 gramme of gray ashes, composed 

 chiefly of carbonate of lime, phosphate and sulphate of lime, 

 silex, and oxide of iron. 



The artificial ulmine was treated with six times its weight qf 

 nitric acid at 38'^ Baume ; it was reduced almost to the con- 

 sistency of honey ; and being mixed with a little water, it as- 

 sumed a deep brown colour, and left an abundance of matter, 

 which well washed and dried was of the colour of Spanish to- 

 bacco. This matter, heated in a glass tube, was consumed with- 

 out emitting light and without fusing; it produced an empyreu- 

 matic vapour, which seemed to be slightly nitrous. Its savour 

 is bitter without being acid to the taste, although it reddens the 

 tincture of turnsole. It is partly dissolved in boiling water, and 

 produces a deep brown liquor which does not disturb a solution 

 of isinglass. The brown acid liquid separated by water from this 

 pulverulent matter, still retains something of the latter; it pre- 

 cipitates tlie animal glue, and furnishes by evaporation crystals 

 of oxalic acid. 



Such are the properties which I have recognised in this sub- 

 stance, produced by the action of potash upon wood, and which 

 I have compared to the ulmine which exudes from the ulcers 

 of trees. I may observe that the latter is also produced '\n 

 a ,alogoas circumstances in diseased trees, the wood of whiclj 

 in puticfying separates quite from the j)otash which nnist con- 

 cur in the formation of the ulmine. I ought not to neglect to 

 slate that M. Vauquclin had already compared this producticm 



of 



