110 Prof. Stromeyer on the Discovery of Cadmium, [Frs. 
precipitate is not redissolved by adding an excess of alkali. By 
ammonia, on the contrary, it is indeed at first precipitated 
white ; but when an excess of the ammonia is added, it is again 
taken up. By carbonate of ammonia, it is thrown down in the 
state of a carbonate ; but when an additional quantity of the 
precipitant is added, the greatest part of this carbonate is again 
redissolved. When this solution is exposed to the open air, the 
carbonate very speedily precipitates again. We may, therefore, 
employ carbonate of ammonia with advantage to separate this 
metal from zinc and copper, when it is mixed with them. 
Prussiate of potash throws down this metal from its solutions 
in acids white; sulphuretted hydrogen, and the hydrosulphurets, 
throw it down yellow. This last precipitate, which, when dried, 
has an orange yellow colour, resembles sulphur auratum, and 
like it is a hydrosulphuret. From its colour and appearance, it 
might, by a careless observer, be mistaken for orpiment ; but it 
is readily distinguished by its more pulverulent form, by its 
appearance before the blow-pipe, and by its easy solubility in 
acids, with the evolution of sulphuretted hydrogen gas. To 
judge from some trials, this compound of sulphuretted hydrogen 
and the new metallic oxide is well adapted for painting, both 
with water and with oil. It forms a very good yellow, which is 
durable ; and in point of beauty is not inferior to chrome yellow. 
This metal is precipitated by zinc from its acid solutions, 
reduced, and in the dendritic state. But copper, lead, silver, 
and gold, are precipitated by it in the metallic state. 
The compounds which this metal forms with sulphur, phos- 
phorus, iodine, and the other metals, I have not hitherto been 
able to investigate with accuracy; though it seems to unite 
readily with several of these bodies ; for example, when heated 
with platinum, it easily melts, and combines with that metal, 
and it forms with mercury a solid crystallizable amalgam. 
Hitherto I have not been able to make it unite with copper. 
These are the particulars which I have hitherto been able to 
ascertain respecting this metal. They are so peculiar that | 
entertain no doubt about it being a new metal quite different 
from every other. As I found it first in the oxide of zinc, I have 
taken occasion from that circumstance to give it the name of 
Cadmium. 
In consequence of the very small quantity in which cadmium 
exists in the oxide of zinc, and the metallic zinc examined by 
me, it has not hitherto been in my power to undertake experi- 
ments to determine the composition of its compounds, the shape 
of the crystals of its salts, and the action of its oxide and salts 
on organized bodies, &c. Indeed the whole of the metal which 
I had for my experiments did not exceed three grammes. I am 
happy, therefore, to be able to inform you, that within these few 
days, through Mr: Hermann, of Schonebeck, and Dr. Rodolff, 
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