346 Huperimenis upon the Formation of Minerals. 
thermal depositions which have served to producethem. I 
do not wish to make this approximation too absolutely, as it 
appears to me to go beyond the immediate interpretation of 
the facts; and I shall limit myself here to the mention of the 
compounds which I have obtained, and the different classes 
of minerals to which they belong. 
Native Metals.—Copper and silver, mixed, but not com- 
bined, as observed in certain mineral repositories in North 
America. Native arsenic. ° 
Oxides.—Red iron ore, Fe, O,; quartz, Si O,, in regular six- 
sided prisms, acuminated with six planes, with striz, and 
sometimes with unequally-developed acuminating planes, so 
frequent in natural crystals. Red copper ore, or red oxide 
of copper, in red shining translucent octahedrons. 
Carbonates.—Carbonates of magnesia, of iron, manganese, 
of cobalt, of nickel, of zine, of copper, or malachite. 
Sulphates.—Sulphate of baryta, in the primitive form. 
Sulphurates—Realgar, in transparent crystals, with the 
colours, lustre, and form, as in mineral veins. Sulphuret of 
antimony, in circular shining metallic-looking crystals. Sul- 
phuret of bismuth, with similar characters as the preceding. 
Sulphurets of iron, of manganese, of cobalt, of nickel, of zine, 
of copper. These last mentioned are massive, as is the case 
with those prepared in our laboratories; but it appears that 
the hydro-sulphuric acid, under certain conditions of tempera- 
ture and pressure, is a solvent of sulphurets, and a general 
agent of crystallization. The properties of this acid explain 
the accumulation of metallic sulphurets in the deep parts of 
mineral repositories, and of metallic carbonates near their 
crop or out-goings. Arsenio-sulphurets, and antimonio-sul- 
phurets were also formed. 
Conclusions.—I had proposed to establish, upon experi- 
mental proofs, the controverted, and, as I think, very probable 
opinion, which attributes the filling up of the concretionary 
veins to incrusting thermal depositions, and to show that the 
formation of a great number of minerals which we there meet, 
whether they be crystallized or amorphous, do not always pre- 
suppose conditions or agents far removed from the actual 
existing causes. We thus, in fact, perceive that the two 
a a 
