392 Miscellaneous [iitel/igence. 



posited no charcoal ; the substance obtained from the neutralized 

 solution was of a deep brown colour, and of a sweet bitter 

 taste. It gave, when heated, vapours of sulphurous acid. 



M. Braconnot then proceeds to shew that by abstracting the 

 elements of water from Avood, it is converted into a substance 

 resembling zilmin. Ligneous fibre is not at all soluble in cold 

 potash, but if equal weights of caustic potash and saw-dust, 

 moistened with a little water, be heated in a platinum or iron 

 crucible, and, continually agitated at a certain point, the wood 

 will soften, and instantly dissolve in the alkali, with much swel- 

 ling. If the crucible be then withdrawn, and put into water, all 

 the mixture will dissolve, except a small earthy residue ; and a 

 deep brown fluid will be obtained, containing potash combined 

 with ulmin ; an acid will separate the latter, which only requires 

 washing to be pure. If the acid liquor be saturated with lime, 

 and evaporated to dryness, alcohol, when digested on it, will se- 

 parate acetate of potash. Wood, thus treated, gives a fourth of 

 its weight of ulmin. 



Artificial ulmin, when dry, is black as jet; it is very brittle, 

 breaking into angular fragments ; its fracture is vitreous, it is 

 nearly insipid and inodorous. When dried, it is insoluble in 

 water, but if just precipitated, it dissolves in small quantities, 

 making a brown solution. It does not contain more than i^Vo 

 of ulmin, but it froths on agitation like solution of natural 

 ulmin. 



When compared with natural ulmin, from the beech tree, by 

 the action of re-agents, it was very similar to it. It combines 

 with potash readily, and neutralizes it. The combination is very 

 soluble, and is precipitated by acids, earthy and metallic salts, and 

 lime water : this combination may, perhaps, be useful as a 

 colour. It combines with ammonia ; it is soluble in concentrated 

 sulphuric acid, -but is precipitated by water ; it dissolves readily 

 m alcohol, and appears, when slowly evaporated, to crystallize 

 from it. The solution is precipitated by water. When heated, 

 it swells and burns with a little flame. 



Such is a brief account of M. Braconnot's paper, but the mat- 

 ter is so excellent, and so free from any thing extraneous, that 



