THE ORIGIN OF MOSS GOLD. 295 
From the foregoing experiments it will be seen that the amount 
of arsenic taken up by the gold varies very much: thus the alloy 
from Experiment 5 (from arsenic and gold) lost 9:647 arsenic, 
and from mispickel and gold 1°82 of arsenic. 
Experiment 6 (from arsenic and gold) lost 7:57 of arsenic 
a Gs ‘3 . 1 ORO Z is 
‘s 8 " “ fe Gera. Fs 
0° ) ” ” ” 3°27 ” 
s, 10 as ., by acre " 
me ial - Fa ce OO) *; 
nf 12 , . un ays * 
er 13 - 3 eee aed. ae 
+ 14 5 5 se lleSlo/, be 
The lowest containing only about 2’/ and the highest nearly 
10% of arsenic. 
While the arsenic is hot it feels sticky when touched with an 
iron wire and the fragments cohere to a certain extent. 
The excess of arsenic left in the lower part of the tube as well 
as the sublimed arsenic shows well developed crystals. 
Experiment 15.—Precipitated gold was mixed with powdered 
purified arsenic in about equal bulks, and compressed into small 
cylinders by means of a diamond mortar and then roasted slowly 
in a muffle ; the gold was left as a porous cylinder, but with 
excrescences of moss gold in places and lining the cavities. 
Experiment 16.—Moss gold was also obtained by roasting a 
cylinder composed of mispickel 1 g. and ‘75.g. of precipitated gold. 
Eaperiment 17.—Gold :75 g. arsenic ‘5 g. and sulphur °5 g. 
were compressed, on roasting, it at once fused down into an 
irregular cake with a very cavernous and spongy structure ; the 
surface was like that of moss gold and under the microscope the 
usual spicules and spirals were seen. The cupel used as a support 
was stained of a purple tint and this penetrated to nearly one- 
eighth of an inch deep, just as if the gold had been in solution. 
