230 KOENIG—ARTIFICIAL PRODUCTION OF CRYSTALS. [June1, 
domeykite crystals and the latter became algodonite. Since the 
algodonite is only found at the base, near the copper, the explanation 
seems to me plausible enough. 
Experiment of January 5, 6, 7901.—A piece of silver was ; exposed 
in the incubator. It was supposed to be quite pure; but, as will be 
‘seen from the analysis, it contained several per cent. of copper. For 
several hours no action appeared to take place, behavior being simi- 
lar to nickel. Then the edges began to round and towards even- 
ing the piece of alloy went into complete fusion at a temperature 
certainly not above 450°C. Seen by candle-light, through the glass 
tube, the material had the appearance of a large drop of mercury, 
being seemingly very mobile. The following morning (with the 
weaker current) it was found solidified, but nosign of crystals. The 
substance broke readily under the hammer; the fracture shows 
cleavage faces.and a light gray color. 
The analysis gave (0.4795 gram): 
Atoms. 
Aoi 7.22 0.688 ee 
Gee 763 
ic—«, Te 0.075 ie 
(Difference) As = 20.96 0.273 
100.00 
Ratio: 
(AgCu) : As = 2.79: 1.00 
There is, therefore, a molecule Ag;As with a tendency, how- 
ever, to pass into Ag,As; some of the latter is shown in the ratio 
%, instead of 3, which corresponds exactly to 4 Ag,As + Ag,As. 
Experiment of January 21, 1901.—Piece of alloy (1 copper, 1 
silver) exposed twenty-one hours. A beautiful growth of thick 
tabular crystals, which sit up on a gray crystalline layer, under 
which appears a thin zone, silver-white in color, 1/2 millimeters 
thick ; then comes copper-red. The growth is entirely in the axis 
of the piece and tube towards the arsenic. 
The analysis of the crystals gave: 
Cu 62'62 0.9844 | 
Ag = satan oateaeip a 
AS = 26.57 0.3569 
100.00 
Ratio: 
(CuAg) : As = 3.05 : 1.00 
