EXTRACTION OF THE PRECIOUS METALS FROM- ORES, ETC. 437 



Emerald Tablet, the Golden Leaves of Abraham, Jew Prince, Priest, Levite, 

 Astrologer and Philosopher, which in the hands of Nicholas Flamel yielded such 

 a rich harvest, the Practical Chemistry of Miriam the sister of Moses, and a mul- 

 titude of grotesque writings ascribed to personages of known reputation. Ray- 

 mond Lully is credited with five hundred worksj Hermes Trismegistus, the mythi- 

 cal Father of Sciences, with several thousand. 



THE EXTRACTION OF THE PRECIOUS METALS FROM ORES BY 



ELECTROLYSIS. 



Mm. Bias and Miest have discovered that if in electrolysis we replace the 

 metal of the anode by compressed sulphur-ores these may themselves serve as an 

 anode. Further, if we place such anodes in a bath of a suitable electrolytic salt 

 having the same metallic base as the metal of the ore, and if we let the electric 

 current act in such a bath, the effect is that all the sulphur of the ore is precipitat- 

 ed upon the anode and falls to the bottom of the bath. At the same time there 

 is formed at the cathode a precipitate or continous deposit' of metal liberated 

 from the salt of which the electrolytic bath consists. The acid of the bath being 

 set free appropriates an equivalent projDortion of the metal contained in the ore 

 placed at the anode. In this manner the neutral electrolytic bath is re-constituted 

 without ceasing and serves indefinitely. 



Electrolysis of Various Sulphuretted Ores. For simple sulphides, 

 without gangue, containing only sulphur and a single metal, is exceedingly easy 

 and complete. If we have an electrolytic bath containing a soluble salt of the 

 same base, e. g., a bath of lead nitrate, in case of the treatment of pure galena, 

 this ore is placed at the anode, when under the action of the electric current the 

 sulphur is deposited at the anode and the lead at the cathode. If the ore con- 

 tains in addition to the metal a silicious gangue, the silica is deposited at the 

 anode at the same time with the sulphur. But these two substances though mix- 

 ed together remain distinct. They fall in part to the bottorri of the bath, and it 

 is advisable to remove the rest from the anodes by an automatic brushing. 



If there are antimony and arsenic in the ore, which are also precipitated at 

 the anode, but chiefly in the state of insoluble oxides, mixed, but not combined 

 together, nothing is easier than to separate them again by electrolysis. 



In case of ores containing exceptionally much arsenic, a part of this during 

 precipitation at the anode combines with sulphur, producing arsenic bisulphide or 

 realgar and the yellow sulphide or orpiraent. 



These products are extracted and purified at first by sulphuretof carbon and 

 afterwards by separate electrolysis in a bath with a feeble electric current, when 

 they yield pure sulphur at the anode and oxides of arsenic and antimony at the 

 cathode. 



If we Operate electrolytically on sulphides containing several metals, those 



VI— 28 



