WRITINGS OF JAMES BMITHSON. 47 



ON A SUBSTANCE FROM THE ELM TREE, 

 CALLED ULMHT. 



From the Philosophical Transactions of the Koyal Society of London, 

 Vol. CIII, Part I, 1813, p. 64.— Read December 10, 1812. 



1. The substance now denominated Ulmin was first made 

 known by the celebrated Mr. Klaproth, to whom nearly 

 every department of chemistry is under numerous and great 

 obligations.* 



Ulmiu has been ranked by Dr. Thomson, in his System of 

 Chemistry, as a distinct vegetable principle, on the ground 

 of its possessing qualities totally peculiar and extraordinary. 

 It is said, that though in its original state easily soluble in 

 water and wholly insoluble in alcohol and ether, it changes, 

 when nitric, or oxymuriatic acid is poured into its solution, 

 into a resinous substance no longer soluble in water, but 

 soluble in alcohol, and this singular alteration is attributed 

 to the union to it of a small portion of oxygen which it has 

 acquired from these acids.* Being possessed of some of 

 this substance which had been sent to me some years ago 

 from Palermo, by the same person from whom Mr. Klap- 

 roth had received it, I became induced, by the foregoing 

 account, to pay attention to it, and have observed facts 

 which appear to warrant a different etiology of its phe- 

 nomena, and opinion of its nature, from what has been 

 given of them. 



The ulmin made use of in the following experiments, had 

 been freed from the fragments of bark by solution in water 

 and filtration, and recovered in a dry state by the evapora- 

 tion 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. 



, * Dr. Thomson's Syst. of Ohem. Vol. IV, p. 696. Fourth edition. 



