1819.) and the Analysis of a new Mineral, 111 
of Magdeburg, who took an interest in this metal, I have been 
placed in a situation which will enable me to carry my experi- 
ments further. 
During the apothecary’s visitation in the state of Magdeburg 
some years ago, there was found in the possession of several 
apothecaries, a preparation of zinc from Silesia, made in Her- 
mann’s manufactory at Schonebeck, which was confiscated on 
the supposition that it contained arsenic, because, when dis- 
solved in acids, and mixed with sulphuretted hydrogen, it let 
fall a yellow precipitate, which, from the chemical experiments 
made on it, was considered as orpiment. This fact could not 
be indifferent to Mr. Hermann, as it affected the credit of his 
manufactory, and the more especially as the Medicinal Coun- 
sellor Roloff, who had assisted at the apothecaries’ visitation, 
had drawn up a statement of the whole, and sent it to Hufeland, 
in Berlin, who published it in the February number of his 
Medical Journal. He, therefore, subjected the suspected oxide 
of zinc to a careful examination; but he could not succeed in 
detecting any arsenic in it. He then requested the Medi- 
cinal Counsellor Roloff to repeat his experiments on the oxide 
once more. This he did very readily. And he now perceived 
that the precipitate which had at first been taken by him for 
orpiment, was not so in reality ; but owed its existence to the 
presence of another metal, having considerable resemblance to 
arsenic, but probably new. To obtain full certainty on the 
subject, both the gentlemen had recourse to me, and have sent 
me, within these few days, both a portion of the Silesian oxide 
of zinc and specimens of the orpiment, like precipitate, and of 
the metal extracted from it, with the request that | would sub- 
ject these bodies to a new examination, and in particular that I 
should endeavour to ascertain whether they contained any arsenic. 
Krom the particulars already stated, I considered it as probable 
that this Silesian oxide of zinc contained likewise the metal 
which I had discovered; and as it gives with sulphuretted 
hydrogen a precipitate similar in colour to orpiment, I considered 
this to be the reason why the oxide was supposed to contain 
arsenic. Some experiments made upon it fully confirmed this 
opinion. I have, therefore, informed Mr. Hermann of the 
circumstance by the post; and I shall not fail to give the same 
information to Medicinal Counsellor Roloft, whose letter I only 
received the day before yesterday. 
__ As this Silesian oxide of zinc contains a much greater propor- 
tion of cadmium the oxide which I examined, amounting, 
according to the experiment of Hermann, to about three per cent. 
1 hope now to have it in my power to procure a sufficient quan- 
tity of this metal to be able to examine it completely. I have, 
therefore, requested Mr. Hermann to send me an additional 
uantity of the oxide by the post; and I hope to receive it in 
the course of next week. 
