Gum, Sugar, and an Acid, ly means of Sulphiric Acld,&c. 1 2'! 



brown liquor is obtained which retains in solution the potash 

 combined with ulniine : an acid separates the latter in the form 

 of a very abundant brown precipitate, which only requires to be 

 well washed. If the acid liquor, separated from this precipitate, 

 be saturated with chalk, and evaporated to dryness, alcohol, when 

 digested on it, will separate acetate of potash. Sawdust thus 

 treated with potash can furnish more than a fourth of its weight 

 of dried artificial ulmine. Old linen cloth gives the same results: 

 it disengages nothing but water, and a small quantity of yellovy 

 empyreumatic oil. 



Dried artificial ulmine is of a black brilliant as jet : it h very 

 brittle, and divides easily into angular fragments. Its fracture is 

 vitreous. It is nearly insipid, and inodorous. In this state cf 

 dryness it is insoluble in water ; but when it has been precipi- 

 tated, it dissolves in small quantities, and communicates a yel- 

 lowish brown colour. The fluid does not contain more than vt;V~ 

 of ulmine in solution ; it bul)bles on agitation like a solution cf 

 natural ulmine. The same artificial substance gives to boilir.g 

 water a deep brown colour like prepared coffee. If nitrate of 

 mercury, or nitrate of lead, is poured upon it, it produces imme- 

 diately brown precipitates, and the liquor is entirely dissolved. 

 It is also precipitated by the nitrate of silver, sulphate of red iron, 

 nitrate of barytes, acetate of alumine, chlorate of calcium, and 

 chlorate of sodium ; but the precipitates do not manifest them- 

 selves till some time after the mixture. Lime water does not 

 produce any change on it ; but if a little lime, in powder, is 

 added, the liquor is greatly discoloured ; and with litharge it is 

 entirely so. 



I ascertained that the ulmine of the bark of the beech-trc-a 

 presents similar results to those I have mentioned. 1 dissolved 

 it in the water of very pure gallic acid with gelatine ; no change 

 was produced ; but by the solution of artificial ulmine there was 

 deposited a weighty brown elastic matter soluble in an excess of 

 gelatine. Artificial ulmine not dried, and heated, reddens paper 

 teinted blue with turnsole. 



The same substance conibines with great facility with potash, 

 and neutralizes entirely its properties. This combination is very 

 soluble in water : it is precipitated abundantly by acids, earthy 

 and metallic salts, and lime water ; evaporated, it leaves a black- 

 ish shining residuum, unalterable in the air, and which, after 

 c6mbuslion, leaves potash. This combination may perhaps be 

 useful as a colour. It combines promptly with diluted ammonia: 

 after l)eing evaporated to dryness, there remains a residuum of 

 the nature of varnish, very soluble in water, and which slightly 

 reddeni^ paper teinted with turnsole. Lime disengages the ani- 

 tnotuikifiin It; ami the acids produce abundant gelatinous prc- 



^ipicat«). 



