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£06 On a Subsiance from the Elm Tree, called Ulmin. 
four grains of ulmin were decomposed by nitric acid, 
They afforded 2-4 grains of resin-like matter. The nitrate 
of potash obtained was heated to deflagration, in. small 
quantities at a time, in a platina crucible to free it from 
resin. The alkali produced was supersaturated with nitric 
acid, dried, and slightly fused. It then weighed 1-2 grains. 
If we admit half of nitrate of potash to be alkali, this will 
denote ;'3, of potash in ulmin. 
Five grains of ulmin were decomposed by mariatic acid. 
The resinous matter weighed 3°3 grains, and the muriate, 
of potash, after being ignited, dissolved away from the 
charcoal, dried, and again made red hot, weighed 1*4 grain. 
If we suppose 2-3ds of muriate of potash to be alkali, this 
will indicate +42, of potash in ulmin. 
Two grains of ulmin were made red hot in a gold cruci- 
ble. It then weighed only 1:05 grain, The form of the 
flakes was in no degree altered ; but they had acquired the 
blue and yellow colours of heated steel, of which they had 
likewise the metallic aspect and lustre, and could difficultly, 
if at all, have been distinguished by the eye from heated 
steel-filings, or fragments of slender watch-springs. Water 
immediately destroyed their metallic appearance. 
Muriatic acid, poured on, caused a strong effervescence, 
and formed muriate of potash, which, freed from all char- 
coal, and made red hot, weighed 0°6 grain, corresponding 
to =2.°. of potash in ulmin. 
These experiments assign about 1-5th for the quantity of 
potash in ulmin; but as it is impossible to operate, on so 
small a scale, on such substances without loss, it is pro- 
bable that it even exceeds this proportion, 
5. The substance separated from ulmin by acids has the 
following qualities : 
It is very glossy, and has a resinous appearance. 
In lumps it appears black ; but in minute fragments it is 
found to be transparent, and of a garnet-red colour. 
It burns with flame, and is reduced to white ashes. 
Alcohol dissolves it, but only in very smal] quantity. 
Water likewise dissolves it, but also only in very small 
quantity. Acids cause a precipitate in this solution, though 
this resin-like matter appears neither to contain any alkali, 
nor to retain any of the acid by means of which it was ob- 
tained. 
{ts solution in water seems to redden turnsol paper. 
Neither ammonia, nor carbonate of soda, promotes its 
solution in cold water. 
On adding a small quantity of potash to water in which 
if 
