SECONDARY ENRICHMENT OF SILVER ORES athe 
sulphide is less. In answer to question (6), we must conclude in 
the light of the hypothesis given that the action of the acid on the 
sulphide was not at an end, nor would it end till the ferric salt 
or the sulphide was used up. This might be tested by a series of 
experiments similar to the above, and Jasting for a year or more; 
but time did not permit such test. 
ACTION OF SOLUTIONS ON MINERALS. SERIES 2 
To make certain that the losses in weight obtained in the last 
table were not due to the presence of soluble impurities in the 
natural sulphides, some of the above experiments were repeated with 
chemically pure substances. For the pyrargyrite used the writer is 
indebted to Mr. Sayrs A. Garlick, of the department of chemistry, 
who prepared it according to Sommerlad’s method.t The other sub- 
stances were prepared by the writer. The results are given in the 
following table. 
SERIES 2 
Solution Mineral Loss of Weight Time Remarks 
\ENI@IES piclaedion Argentite 0.0010 gm. 98 days 
A 5 cp eee Argentite . 0019 98 
Avie 3i Tee ees || Areentite .0062 98 
Aeieeat soe. | Areentite .0074 98 
Waters... 2c... Pyrargyrite .OIII IOI 
PAPAS jcc. = Pyrargyrite .0093 101 
neato Pyrarcyrite .O120 IOI 
LXGINOGs IGe eee Pyrargyrite .O125 IOI 
ANSI G85 gor Sete Pyrargyrite .O144 IOI 
WatteR esc, cis o .2i Stibnite .O175 84 Weights give weight of 
Sb.0, obtained from 
analysis of solutions 
iho SOs Oe eee Stibnite .0205 84 
ANG IRGC te peewee Stibnite .0185 84 
BeOnEen ene 4 Otibnite .0160 84 
ID eco niga gee nee Silvemchloride sis. a... 33 Solutions gave no Ag 
F:H,0::1:1....| Silver chloride . 0000 33 
IN SELSO).  ox.. Silver chloride 0000 33 
It will be seen therefore that the reactions noted in Series 1 
and 2 are of the same class. The values obtained in Series 2 are 
perhaps somewhat smaller than those in Series 1, but this may have 
tH. Sommerlad, Zezt. anorg. Chemie, XV (1897), 173- 
