Analysis of the New-Jersey Ores of Zinc. 321 
2. I precipitated the two oxids from their solution, by 
means of an alkaline sub-carbonate, having taken the pre- 
caution to boil the liquor, that it might not retain any por- 
n: I calcined the precipitate with the contact of air, till 
the manganese was oxidized to a maximum, and afterwards, 
in one trial, I treated it with nitric, and in another with 
acetic acid—-I evaporated it gently to dryness, and treated 
it again with water. Oxid of manganese remained perfect- 
ly pure, but the solution which contained the zinc, retained 
also a notable quantity of manganese ; and when this solu- 
tion was precipitated by an alkaline carbonat, the calcined 
precipitate was of a dirty yellow, more or less deep. By 
treating this precipitate anew, by means of acetic acid, a 
little oxid of manganese is separated, but much the greater 
part always remains with the oxid of zine. 
3. I precipitated the two oxids by caustic potash in ex- 
cess, and allowed it to digest for some time—it was then 
filtered. The liquor contained nothing but oxid of zine; 
but the residuum contained still a large quantity of this oxid, 
and it was necessary to redissolve, to precipitate anew by 
potash, and to repeat this operation many times, in order to 
complete the separation. * 
4. I precipitated the solution of the mineral by an alka- 
line carbonate, and through this solution diluted with water, 
passed a stream of chlorine in excess—I obtained a violet 
Coloured liquor and a black residuum. ‘The liquor being 
evaporated in the air, became colourless, and deposited 
pure oxid of manganese. The black residuum having been 
treated by acetic acid, now contained nothing but oxid of 
manganese. The two liquors containing the zinc, were 
precipitated by a sub-carbonat. The calcined precipitate 
had a light yellow tolour, and it was found to contain about 
ho part of its weight of oxid of manganese. [1 is proba- 
ble, that by washing very carefully with abundance of wa- 
ter, the precipitate of zinc and manganese, and by agitating 
it for a long time with chlorine, no particle of the carbonate 
of manganese would escape the action of this agent, an 
that the two metals would be perfectly separated. 
5. M. Berzelius has had the kindness to communicate to 
me the following method which has perfectly succeeded. 
I precipitated by an-alkaline carbonate, washed the precipi- 
tate by decantation, digested it for sometime while stil 
