Mr, Smithson Ofi a Substance from the Elm Tree, ^c. 65 



been freed from the fragments of bark by solution in water 

 and filtration, and recovered in a dry state by the evaporation 

 of the solution on a water bath. 



2. In lumps, ulmin appears black, but in thin pieces it is 

 seen to be transparent, and of a deep red colour. 



In a dilute state, solution of ulmin is yellow ; in a concen- 

 trated one, dark red, and not unlike blood. 



When solution of ulmin dries, either spontaneously or by 

 being heated, the ulmin divides into long narrow strips dis- 

 posed in rays to the centre, which curl up and detach them- 

 selves from the vessel, and the fluid part seems to draw 

 together, and becomes remarkably protuberant. Solution of 

 ulmin slowly and feebly restores the colour of turnsol paper 

 reddened by an acid. 



3. Dilute nitric acid being poured into a solution of ulmin, 

 a copious precipitate immediately formed. The mixture was 

 thrown on a filter. The matter which has been considered as a 

 resin remained on the paper, and a clear yellow liquor came 

 through. This yellow solution, on evaporation, produced a 

 number of prismatic crystals looking like nitrate of potash. 

 They were tinged yellow by some of the resin. This, mix- 

 ture, heated in a gold dish, deflagrated with violence, and a 

 large quantity of fixed alkali remained. 



Dilute muriatic acid caused an exactly similar precipitation 

 in solution of ulmin to nitric acid, and the precipitate was the 

 same resin-like substance. The filtered liquor afforded a quan- 

 tity of saline matter, which, after being freed by ignition from 

 a portion of dissolved resin, shot into pure white cubes of mu- 

 riate of potash, as appeared by decomposing them by nitrite 

 acid. 



MDCCCXIII. " K 



