234 KOENIG—ARTIFICIAL PRODUCTION OF CRYSTALS. [June1, 
is composed of crystals of the domeykite habitus, thin and thick 
tabular ; all but very few show rounded edges—that is, incipient 
fusion. <A part of the crystals was removed. Material (@). 
Analysis of a (0.4801 gram); many individual plates, others 
grown together. ¢ 
Cu — 69:70): 637 — 0.1078 
As = 20.32: 75 = 0.2709 
Sb= 9.74: 122 —0,0800 03509 
99.85 
Ratio: 
Cu : (AsSb) = 3.11 : 1.00 
These crystals are thus proved to be stdiodomeykite. It also fol- 
lows that higher temperature increases the ionic mobility of the 
antimony. 
The analysis of the material (a’) (0.4823 gram) gives: 
Cu == 45. 10':)63.== 0.7158 
Sbi== 36.83 2122013059 0.5428 
AS 18:07 175. —'0:2406 
100.00 
Ratio: 
Cu): (SbAS)i=— 4,32): 1,00) — Aiea 
I take this to mean a mixture in which the outer crust is Cu (SbAs), 
whilst the inner layer is Cu,(SbAs) 2; 1/71 +3/2—4/3. 
Experiment of February 7.—A fragment of the alloy Cu,Sb was 
again exposed with the intention of keeping the temperature, if 
possible, below that of the one preceding, and yet higher than in 
the first experiment. The exposure was forty hours. It must be 
remembered that owing to the local conditions a perfectly uniform 
temperature could not be maintained unless the ammeter were under 
steady observation—an impossible or at any rate too difficult a pro- 
position. Hence the temperature would steadily decrease, whilst 
the potential sank from 120 to 110 volts and would rise (during the 
night) to 125 volts, when in the forenoon the dynamo was coupled 
to the storage battery. 
The original alloy was found covered with three products : 
1. A fine granular crust. 
2. Over this a peculiar sort of crystals not showing any one of 
