COLLECTIONS IN ECONOMIC GEOLO(!V AND METALLURGY. 55 



cieutly it is drawn off iuto large kettles, where it is kept melted, aud 

 metallic zinc in several portions is successively added. This zinc forms 

 an alloy with the silv^er and rises to the top of the melted lead, when it 

 is skimmed off. These zinc scums containing- tbe silv^er are gently 

 heated for a considerable time (li<piated) to remov^e excess of lead; the 

 liquated scums are then subjected to distillation to remove the zinc. 

 The resulting alloy of silver aud lead is then melted in a cupel and sub- 

 mitted to oxidation, whereby the lead is removed in the form of litharge, 

 and the silver remains behind as metal, which is cast into ingots and 

 sold. 



The lead from which the silver has been removed by zinc retains a 

 small amount of zinc, and this is removed by oxidation in a furnace 

 similar to the softening furnace. From this furnace it is drawn off iuto 

 a kettle and poled with green wood to purify it. The market or soft 

 lead of commerce from the kettle is cast into pigs and sold. 



THE CHELTENHAM SMELTING AND REFINING WORKS. 



These works are located just outside of St. Louis, Missouri, and 

 draw their suj^ply of ores from the whole western mining region. The 

 collection shown is confined to the refining operation and is selected 

 from a complete collection of the works taken by Mr. J. P. Gazzam, 

 E. M., September, 1884. 



(1) Base bullion, from blast-furnaces uieltiug. (57386.) 



(2) First skimmings from softening furnace. (57387.) 



(3) Second skimmings from softening furnace. (57388.) 



(4) Softened base bullion. (57.389.) 



(5) Spelter (metallic zinc), used to desilverize the lead. (57.390.) 



(6) Zinc scums, containing the silver of the base bullion, from the desilverizing 

 kettles. (57391.) 



(7) Desilverized lead, containing zinc. (57392.) 



(8) Skimmings from the refining furnace, containing zinc. (57393.) 



(9) Poliugs from refining kettle. (57394.) 



(10) Market lead. (.57395.) 



(11) Zinc, distilled from scums. (57398.) 



(12) Rich silver-lead alloy, remaining in tlie retorts after distilling the zinc ; con- 

 tains gold. Dor6 alloy. (57397.) 



(13) Rich silver-lead alloy, remaining in the retorts after distilling the zinc. 

 (57396. ) 



(14) Litharge, from cui»elling Dore alloy. (57400.) 



(15) Litharge, from cupelling silver-lead alloy. (57399.) 

 (1(5) Fine silver. (57401.) 



(17) Coal, used for fuel. From Bryden, Illinois. (57404.) 



(18) Coke, from Bryden coal. (57405.) 



KANSAS CITY SMELTING AND REFINING C03IPANY. 



To illustrate tne smelting of base bullion and the refining of the bul- 

 lion combined, a collection from the works of the Kansas City Smell- 

 ing and Refining Company at Argentine, Kansas, is shown. 



The process of smelting base bullion foUow^ed here is, in general, the 

 same as at South Pueblo, Colorado, the principal difference being that 



