1883.] Mineralogy. 653 
precipitation of gold from its chlorine solution, while other metal- 
lic and mineral constituents of the same solution are unaffected. 
The gold is thus both deposited and refined. All that is neces- 
sary is to pass the solution of the gold ore through a charcoal 
filter, when the gold in a pure state is deposited upon the char- 
coal, which may then be burned and a button of gold readily 
ined, 
This discovery, so simple in its method, was at first ridicule 
by chemists. Repeated experiments have, however, shown its 
efficacy. Not only are no other substances than gold thus de- 
posited, but the gold itself is completely separated from its ter- 
chloride solution, the liquid after having passed through the 
charcoal containing not even a trace o gold. As copper is not 
affected by the passage through the charcoal filter, that metal 
may be afterwards deposited by contact with scrap-iron. Silver 
would already have been precipitated as chloride in the original 
Solution. By this process, therefore, gold, silver and copper may 
each be separated by most inexpensive methods from the same 
. 
solution 
eposited, not from any affinity for carbon, but simply because 
the chlorine in which it was soluble has been taken away to form 
hydrochloric acid, in which gold is insoluble. It also follows 
that copper and other metals soluble in hydrochloric acid are not 
affected by the conversion. 
_ CRYSTALLIZED SERPENTINE FROM DELAWARE.— Professor H. C. 
Lewis! has described certain crystals of serpentine which occur 
in the deweylite of Way’s quarry, Delaware. The deweylite con- 
tains angular fragments of quartz, such as would be produced by 
rowing a heated quartz crystal into cold water. It also contains 
rounded masses of feldspar which are more or less altered into 
deweylite. The deweylite is thus shown to be probably the 
result of the alteration of graphic granite. 
_1€ crystals of serpentine, of a smoky pearl color, have a 
p caceous cleavage, and in the polariscope are shown to be 
axial with a small optic-axial divergence. The physical and 
chemical characters, including an analysis by Mr. Haines, are ` 
Siven, and the mineral is proved to be a true serpentine. The 
“€avage and the optical characters show that it is crystallized. 
X Tue Fiuorine Mrnerats—In an extended review of the 
~ Orne minerals, by Professor P. Groth? our knowledge of these 
3 ee Acad. Nat. Sci. Phila., Feb., 1883. 
€itschr, f. Kryst., etc., VIT, 4th and sth Nos. 
