Intelligence and Miscellaneous Articles. 899 
of phosphoric acid in this mineral, I fused it, after reducing it to a 
very fine powder, with a mixture of potash and soda, and after get- 
ting rid of the phosphoric acid in the usual manner, I precipitated 
the copper from a slightly acid solution by means of sulphuretted 
hydrogen. The analysis, in which the quantity of phosphoric acid 
was determined by the loss, gave— 
PRIMED. etch. ar Be 31°55 16°39 
Alumina ju fs! i'2),.deve 0°53 0°25 
Oxide of copper.... 33°14 6°67 
Magiibsin?.< 3). a2¢ 6 8i15 0°60 
Water: 1¢ sa 2.5023 23°03 20°47 
Phosphoric acid.... 10°22 5°73 
I believe it is still too soon to attempt to determine, before the 
_analysis has been repeated, the mode in which these substances are 
combined with each other; but we see nevertheless that Demidovite 
contains silicates and phosphates of copper, with water and phos- 
phates of alumina and magnesia, but the latter in very minute pro- 
portions*. It must also be remarked, that one-third of the water 
escapes at a lower temperature than the other two-thirds. 
Demidovite, like Wolkhonskite, Hisingerite, and several other 
minerals, is perfectly amorphous, and is no doubt still being pro- 
duced. At Taguil, as in the whole of the Ural, a geological fact 
occurs to which sufficient attention has not been paid,—this is the 
great depth to which the rocks are either decomposed, or at least 
cleft into larger or smaller fragments. Even at the depth of more 
than 70 sagenest, which is reached by the copper mine of Taguil, the 
rocks are almost all destroyed, except the limestone by which the 
mine is surrounded. In 1848 I saw a large isolated block of mala- 
chite laid bare at a depth of 45 sagénes ; as might be supposed, all the 
mammillae were turned downwards, and the outer surface had so 
little consistency and was so friable, that it was detached by the 
finger ; sometimes the specimens of malachite present in their inte- 
rior a fragment of native copper, surrounded by red copper and ma- 
lachite, sometimes mixed with Demidovite, Taguilite and phospho- 
rocalcite. In the upper parts of the mines few metallic sulphurets 
are met with, but the quantity of these increases gradually in pro- 
portion as the bottom is approached.—F’rom the Bulletin des Natura- 
listes de Moscou. 
ON THE BEHAVIOUR OF THE NATIVE METALLIC SULPHURETS 
TOWARDS MURIATIC ACID UNDER THE INFLUENCE OF GALVA- 
NISM. BY M. VON KOBELL. 
When copper pyrites is moistened with muriatic acid (1 vol. of 
concentrated acid to 1 vol. of water), no change takes place in the 
* If we take no notice of the phosphates of alumina and magnesia, we 
may deduce the formula 5CuO $i0*+ CuO PO’+18HO, which requires— 
Fal O Ae as RRA ack: 
71 C110 Reinet arena Oil. 
Eee, sett ea) OP LO LO 
LO tires ben ee ae oo: OG 
99°99 
+ The sagéne = 7 English feet. 
