1852. ] 113 
A portion of the alcohol (reacting acid like the honey) neutralized by caustic 
potassa, then distilled with sulphuric acid, gave an aqueous acid liquid, which, on 
addition of nitrate of silver, gave a whitish precipitate, becoming black on boil- 
ing, rendering the supposition of formic acid probable. 
The Committee on the two papers by Dr. Genth, entitled respectively 
‘“‘On some Minerals which accompany Gold in California,” and “On 
Strontiano-Caicite, a new Mineral,’ reported in favor of publication in 
the Proceedings. 
On some Minerals, which accompany Gold in California. 
By Dr. ¥. A. Gentu. 
A few days ago I had an opportunity of examining a lot of Gold from the north 
fork of the American River, 30 miles from Sacramento City. 
The gold was in very fine scales and but a few larger pieces among them. 
The following minerals have been found mixed with it, viz.: 
-1. Hyacinth in almost microscopte crystals, of different lengths. The longer 
ones exhibit the form of the primitive square octahedron combined with the 
second square prism; the shorter ones have besides, a second octahedron, a 
double eight-sided pyramid and the first prism; one of the crystals I found having 
a basal plane besides. They are colorless or show a smoky tinge; only a few 
less perfect crystals have a grayish-brown color. Lustre perfectly adamantine. 
2. Chromic Iron in rounded grains, which sometimes show faces of the regular 
octahedron. Color between jet-black and iron-black. Lustre submetallic. 
Streak brown. Not magnetic. Before the blowpipe with borax it gives in both 
flames emerald-green beads. The powder was decomposed by bisulphate of 
potash, and the presence of sesqui-oxide of iron and chromium likewise ascer- 
tained in the moist way. 
3. Ilmenite occurs in iron-black grains, which show sometimes distinctly a 
basal cleavage. Lustre submetallic. Streak brownish, and iron-black. Before 
the blowpipe it gives a blood-red bead, which, when saturated, can be easily 
enameled. ‘The powder is easily decomposed by bisulphate of potash; the fused 
mass dissolves completely in diluted hydrochloric acid, and this solution, when 
evaporated, lets fall a white powder, which gives with borax and microcosmic — 
salt the characteristic reactions of titanic acid. The solution in hydrochloric 
acid contains nothing but sesqui-oxide of iron. 
[Both Chromic Iron and Imenite seem to have been confounded with magnetic 
iron.] 
4. Platinum.—A few steel-colored rounded grains were observed, and of 
d. Iridosmine, a few lead-colored scales. The quantity of both Platinum and 
Tridosmine was too small for further examination. : 
I will mention here, that I have examined some white grains and scales from 
Stanislaus in California, which were presented to.me by Prof. John Frazer, 
whose brother had them collected. 
The few scales of gold mixed with them were extracted by diluted aqua regia. 
I then treated them with concentrated aqua regia as long as it acted upon. 
The solution contained almost pure bichloride of platinum with but a trace of 
iridium; neither rhodium nor paliadium could be detected in it. 
The residue consists of six-sided scales. of a color between lead- and tin-white. 
On heating them upon platinum foil, they give out a strong odor of osmium; they 
are therefore the combination Ir Os4 (or Ir Os3) known under the name of Sis- 
serskite. Being heated thus, most of the scales become iridescent and assume, 
like steel, yellow, orange and blue colors. I do not know that this reaction has 
been observed. In order to ascertain whether every kind of iridosmine gives it, 
