280 Mr. R. Phillips on a [Ocr. 
gave out, when placed on a burning coal, an empyreumatic smell 
of animal matter. It is this animal substance, doubtless, which 
imparts to the aqueous solution its opaline appearance. 
After the liquor had been filtered, in order to separate the red 
matter, it was saturated with carbonate of lime, the precipitated. 
sulphate removed by a second filtration, and the fluid evaporated 
to the consistence of a thick syrup. This did not crystallize ; 
it seemed to be more saccharine than the gum was prior to the 
operation, but was insoluble in alcchol. This gum, therefore, is 
not of che same kind as that obtained from starch, by the corre- 
sponding treatment with sulphuric acid. 
Treated with nitric acid, it yielded much oxalic acid, and a 
small quantity of yellow bitter matter, but no mucic acid: this 
proves that itis not a truegum. A gramme of it burnt in a pla- 
tinum crucible left a centigramme of ash, containing phosphate 
of lime, iron, and a particle of silica. 
M. Vauquelin concludes, that this curious substance did not 
exist ready formed in the vesou, but that it was produced from 
the sugar contained in it. 
ArTICLE XIII. 
On a peculiar Sulphate of Alumina. By Richard Phillips 
ERS. 1. & B, Se. : 
INTENDING some time since to obtain a solution of sulphate of 
alumina in a state as nearly as possible approaching to satura- 
tion, I decomposed some alum by means of carbonate of soda, 
and after washing the precipitated alumina, I put it, while moist, 
into sulphuric acid, moderately diluted with water. Although 
the acid appeared to have taken up as nearly as much alumma 
as it was capable of dissolving, I nevertheless added alumina 
occasionally, until at last it remained floating in the solution. 
I now separated the alumina undissolved, and filtered the 
solution, the specific gravity of which was very considerable ; 
upon mixing a small quantity of it with water, I was surprised 
to find that it became turbid, and nearly as much so'as when 
muriate of antimony is decomposed by it ; indeed the alumina of 
a single drop of the solution was apparent ina pint of water. As. 
far as I am acquainted with the properties of alumina, a sulphate 
decomposable by water has not been before observed; and it 
may be remarked that it is an additional point of resemblance 
between an earth and metallic oxides. 
After the solution had been filtered, I observed that a 
deposit was almost immediately formed in the bottom of the 
bottle in which it was kept; this was separated, and a further 
