322 Analysis of the New-Jersey Ores of Zinc. 
moist, in ammonia ; it became immediately brown, and the 
filtred liquor gave by ebullition a white deposit, which, by 
calcination, became perfectly white; it was the pure oxid 
of zinc: but I remarked that the deposit that was insoluble 
in ammonia, almost invariably contained oxid of zinc, some- 
times in considerable quantity. ‘To remove it entirely we 
formed in the acetous fluid, by means of the alkaline car- 
bonate. In this manner we separate the two oxids perfect- 
ly, and with the greatest precision. 
6. Indeed, I have thought, that the zinc being very vola- 
tile, and its oxid easily reducible, we may readily separate 
it, in the dry way, from the oxid of manganese. This was 
practically verified. The oxids were mixed with a deter- 
minate weight of powdered charcoal, and the mixtire pla- 
ced dans un tét étrort, slightly hollowed, which was covered 
by a larger head, perforated in the upper part with little 
holes, a white heat was applied and a very abundant white 
vapour was disengaged. 
As soon as it was certain that this disengagement had 
ceased, the head was uncovered, and the matter which it 
contained was roasted in order to burn out the remaining 
charcoal ; the residuum, which was brown, was weighed, 
and to obtain the exact proportion of the manganese, the 
weight of the ashes which the charcoal would leave was 
subtracted, a weight which had been previously determined 
by experiment. ‘The oxide of manganese proved on eX- 
amination not to contain the smallest quantity of zinc. 
_ All these trials almost exactly agree in giving for the ré- 
sult of the analysis of the manganesian oxid of zine : 
idofzinc, - - - = 0,8 
Red oxid of manganese, - 0,12 
1,00 
It is difficult to say in what degree of oxidizement the 
manganese exists in this mineral. Its colour, and the ap~ 
pearances which it presents with the muriatic acid, render 
it probable that it is, at least, in the state of deutoxid. fo 
order to be certain that the union so difficult to be ever 
the nnn et eee an ree 
