204 Ona Substance from the Elm Tree, called Ulmin. 
and you think it worth making public, I shall thank you 
to insert what I have written in your valuable Magazine. 
J am, sir, yours, &c. 
Leskeard, Sept. 17, 1813. - CoRNUBIENSIS. 
*,* The coincidence of effect noticed by our Correspon- 
dent does not necessarily indicate identity of cause. An 
electrified body has a disposition to give off its charge ; and 
moveable matter, forming the electrified body, or in con- 
tact with it, will be disposed .to go off im small portions, 
each of them performing the office of a carrier to remove 
part of the electric charge, as in the familiar experiment 
with light bodies thrown on acharged plate. In this way 
we may conceive motion to be given to the electrified water 
in the capillary tube, tending to throw it off. 
The similar effect produced by heat may be accounted 
for from the increased tenuity of the liquid, and the en- 
larged aperture of the capillary tube, by the action of the 
heat, both tending to increase the discharge.—T. 
XXXV. Ona Substance from the Elm Tree, called Ulmin. 
By Jamus Smiruson, Esq. F.R.S,* 
1. Tae 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 f. 
Ulmin bas 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 ex- 
traordinary. 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 t. 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. Klaproth had received it, I became in- 
duced, by the foregoing account, to pay attention to it, 
and have observed facts which appear to warrant a different 
etiology of its phenomena, and opinion of its nature, from 
what has been giver of them. 
* From the Philosophical Transactions for 1813, part i. 
+ Dr, Thomson’s Syst. of Chem. vol, iv. p. 696. Fourth edition. 
The 
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