12 On a new Variety of Ulmm. [July, 



It possesses the following properties, which distinguish it from 

 the ulmin of the elm : — 



1. Its colour is a very dark brown, almost black, and it leases 

 a chocolate coloured stain on paper. It readily crumbles to 

 powder between the fingers. Lustre, resinous. Taste, more 

 astringent than the ulmin from the elm, and inclining to bitter. 



2. Dissolves readily in water. The colour of the solution is 

 dark brown, and so intense as to be opake. When left to spon- 

 taneous evaporation upon a watch-glass the ulmin remains, 

 divided into a great number of minute portions by sections, 

 which issue in rays from the centre, and the ulmin adheres but 

 weakly to the glass. 



3. Insoluble in alcohol and ether. 



4. When the aqueous solution is dropped into alcohol of the 

 specific gravity 809, brown flocks precipitate, but the alcohol 

 retains a brown colour, and of course a portion of the ulmin 

 remains in solution. 



5. The aqueous solution is not precipitated by the solution of 

 gelatine in water. 



6'. Some of the precipitates which the aqueous solution of this 

 variety of ulmin forms with the metalline salts differ in colour 

 from the precipitates formed by the ulmin from the elm. The 

 following were the metalline salts tried: — 



(1.) Sulphate of iron is thrown down dark green, and the 

 colour is permanent, though the liquid be left 24 hours in an 

 open glass. 



(2.) Sulphate of copper is precipitated also green. 



(3.) Sulphate of zinc is precipitated brown, and the colour of 

 the precipitate speedily deepens, and becomes at last a dirty 

 black. 



(4.) Nitrate of silver is precipitated in brown flocks. 



(5.) Acetate of lead is precipitated in brown flocks. 



7 \ The aqueous solution is precipitated in brown flocks by a 

 few drops of nitric acid. This solution being evaporated to 

 dryness in a watch-glass, a yellow tasteless powder remained, 

 insoluble in alcohol, but soluble in water. This powder was 

 charred at a very moderate heat ; owing probably to the action 

 of the nitric acid which it still retained. 



Acetic acid does not precipitate this variety of ulmin from 

 water. 



8. Neither potash, carbonate of potash, nor ammonia, precipi- 

 tate it from water. 



'.). When exposed to heat it swells up like gum, and readily 



burns away before the blow-pipe, leaving behind it a minute 



portion of white matter, which did not melt by the continuation 



of the heat. This matter dissolved with effervescence in nitric 



, except some hardly perceptible flocks, which had the 



