232 KOENIG—ARTIFICIAL PRODUCTION OF CRYSTALS, [June1, 
This is the single instance in which the metal exceeds the 3 ratio, 
if we exclude the instance of the algodonite. I venture to explain 
it by a similar process of retrogression, or, perhaps, better, by 
ingression of the still very mobile metal ions into the molecule # 
after the arsenic vapor had become too rarefied for addition from 
the outside, as the temperature was sinking—z.e., the current going 
down. All the experiments with the copperssilver alloy prove: 
1. Silver and copper together replace one another isomorphously 
in the molecule ?. 2. The representation is 63 Cu by 107.6 Ag— 
z.e., divalent copper with monovalent silver. 3. There isa molecule, 
Ag,As, whose melting-point is below the temperature of forma- 
tion ; hence not crystallizable in the incubator. 4. Higher temper- 
ature tends to forming Ag,As, same as Cu,As, 
5. THE ACTION OF ARSENIC VAPORS UPON AN ALLOY OF COPPER 
AND ANTIMONY—STIBIODOMEYKITE, 
If copper and antimony were melted together in such proportion 
as Cu,Sb, which corresponds nearly to copper 3 parts, antimony 1 
part, in percentage Cu = 75.6, Sb = 24.4, and such an alloy were 
to be exposed at the proper temperature to the arsenic vapors, one 
might be justified in supposing that by simple addition of one atom 
of As we would get 
Cu,Sb + As = 2 Cu,(SbAs) 
if there were a tendency in the elements to form such a combina- 
tion; or if the molecule Cu,Sb(Cu = 66 Sb = 34) were exposed, 
then one As might couple together two molecules of Cu,Sb. 
Experiment of February 1, 2, 3, 1901.—The alloy Cu,Sb was 
exposed for three days and nights at very low temperature. In 
the absolutely dark room the wire coil showed dull redness. Very 
large tabular crystals form, drawn in the axis of the tube forward 
the arsenic. The crystals have the color and habitus of domey- 
kite. Their composition is: 
Cu= 69.34 
(0.1422 gram) Sb= _ 1.26 
(By difference) As — 29.40 
100.00 
Ratio: 
Cu: CASSb) = 2.76): 1.00 
