COLLECTIONS IN ECONOMIC GEOLOGY AND METALLURGY. 57 



(3) Cerussite, crystallized, stained with oxide of iron and showing a little un- 

 altered galena. (65173.) 



(4) Cerussite, stained with oxide of iron; crushed sample taken from a large 

 amount of ore for assay : coutaininu' (54 per cent, of lead and 14 ounces of silver per 

 ton. (54999.) 



(1) A sample of litharge from the cupel furnaces such as is charged into the shaft 

 furnaces is shown with the ores. (55007.) 



To illustrate the fluxes three samples are shown : 



(1) Iron scale, consisting of a mixture of metallic iron with oxides of iron. The 

 metallic iron acts as a reducing agent by combining with the sulphur of the galena 

 thus setting the lead free. (55004.) 



(2) Cinder, from iron puddle mill. (5.5006.) 



(3) Limestone. (55001.) 



(1) A single sample of Connellsville coke illustrates the fuel used. (55003.) 



Bight samples of the products of the blast furnace smelting are 

 shown : 



(1) Base bullion, containing the silver and lead of the charge, together with some 

 impurities. (55009.) 



(2) Slag, clean ; too poor in lead and silver to be utilized, is thrown away. 

 (55011.) 



(3) Slag, rich ; containing sufflcient lead and silver to be resmelted. The produc- 

 tion of this rich slag is avoided as much as possible. (55008.) 



(4) Matte, No. 1. A by-product of the smelting operation which is drawn oii' with 

 the slag and settles to the bottom of the pot. Consisting of various sulphides, espe- 

 cially iron, and containing most of the copper of the charge. (55013.) 



(5) Matte, crushed and roasted in reverberatory furnace to remove the sulphur so 

 that it can be recharged into the furnace. (55016.) 



(6) Matte, No. 2, or concentrated ; produced when charging roasted first matte. 

 Contains sufficient copper to be smelted for that metal and is sold to other works 

 for this purpose. (.55018.) 



(7) Speiss, a by-product, consisting mainly of arsenide of iron, thrown away. 

 (55014.) 



(8) Flue dust, consisting of material carried over by the blast and collected in the 

 dust chamber attached to the furnace. (55015. ) 



The illustrations of the refining process are : 



(1) Dross, taken from the softening furnace ; consisting of the unfused impurities 

 of the base bullion with some metallic lead. Taken from the furu.tce as soon as tlie 

 lead is melted. (.55019.) 



(2) Litharge, from the concentrating ciipel; con.sistiug of oxide of lead formed 

 during the oxidation of the lead in concentrating the silver-lead alloy. (.55021.) 



(3) Bottom of concentrating cupel, charged with litharge. (.55024.) 



(4) Litharge, from tinishing cupel ; oxide of lead formed in removing the lead 

 from the silver. (55023.) 



(5) Scums, from the refining furnace ; formed in removing the zinc from the de- 

 silverized lead. (.55027.) 



(6) Lead, soft or market lead. The final result of the process, which is sold for 

 consumption. (55026.) 



Lead Ores. 



THE southeastern MISSOURI LEAD REGION. 



This is one of the oldest and best known mining regions in the coun- 

 try. The first mining operations were carried on in 1720 by the famous 

 Law Company, of Paris, As tin' lead is found near the river, the 



