320 Analysis of the New-Jersey Ores of Zine. 
brilliant, lamellar in one direction and slightly conchoidai 
in the other; the thin slivers are transparent ; it is fragile, 
easily scratched by steel; easily pulverized ; the powder is 
of a beautiful orange red. After long exposure to the air 
it becomes covered with a white pearly coating, which ap- 
pears to be composed of the carbonates of zinc and man- 
ganese. Its specific gravity, according to Bruce, is 6.22. 
With the common blowpipe it is infusible without addi- 
_ tion; with borax it gives a yellowish translucent glass. 
Under the flame of the blowpipe fed by oxigen and hydro- | 
gen it is volatilized, diffusing at the same time a brilliant 
white light. It loses nothing by calcination; while it is 
hot it appears brown, but as it cools it gradually resumes 
its pristine colour. 
It easily dissolves in the cold in the mineral acids, and 
even in the acetic acid. During the solution heat is evoly- 
ed, but without effervescence, and the liquor remains col- 
ourless. Still, with the muriatic acid it produces a solu- 
tion of a brownish red, which, without the disengagement 
of any gas, gradually loses its colour: it is probable that a 
little chlorine is really but very gradually disengaged.* 
The oxids of zinc and manganese appear to have a great 
disposition to unite, and their complete separation is very 
difficult. ‘T’o accomplish this object, I have employed six 
processes, of which I proceed to announce the results. 
1. I have repeated the process of Bruce, which consists 
in pouring into a nitric solution of the two oxids the oxalic 
acid, as long as there is any precipitate, and then in wash- 
ing and calcining the residuum. Bruce regarded the cal- 
cined precipitate as pure oxid of zinc; but ‘Thave remark- 
ed, that it always retains a very notable quantity of manga- 
nese, and that this is the reason why it always retains a foul 
yellow colour, more or less deep—a fact which Bruce ob- 
served without searching for the cause. ‘The oxid of man- 
ganese is almost perfectly pure, and contains only that por- 
tion of iron, which, when the solution has not been made 
with the greatest caution, is accidentally present. Bruce, 
then, was able to obtain by this process, only an inferior 
quantity of manganese, to what really exists in the manga- 
nesian oxid of zine. 
* We are not told whether the odour of chlorine is perceptible.—Ldator. 
