EXPLANATION OF PLATES. XIII 



The lowest gable of the main buildinji; covers the paa floor, and to the left ami far- 

 ther back, is the retort house. lu front of the mill is a large deposit of tailings 

 (Cat. No. 51189, U. S. N. M. From photograph.) 



PLATE VI ^Page4f)). 



SILVEK-LEAD. 



Base-bullion smelting. — General view of the works of the Colorado Smelting Company, 

 South Pneblo, Colorado, generally called "Colorado Smelter." 



In the background, at the left, are the works of the Colorado Coal and Iron Com- 

 pany; next to these are the residence of the manager, general and assay offices of the 

 Colorado Smelter. In the middle ground, to the left, is the sampling mill, where all 

 the ores are received, crushed if necessary, and sampled for assay and analysis, so as to 

 ascertain their character, the treatment necessary, and how to mix them in theshalt- 

 furnace charge. From the sampling mill a tramway leads to various parts ot the works. 



Near the center of the middle ground are the roasting stalls and draft stack; to the 

 right are the ore bins and reverberatory roasters, with draft stack. In the middle of 

 the foreground is the blacksmith shop; to the right of this is the engine house, and to 

 the right of this the shaft furnace house, containing four furnaces, and at the extreme 

 right is the draft stack of the shaft furnaces. In front of the engine house and shaft 

 furnaces is the slag dump. 



(Cat. No. 51092, U, S. N. M. From photograph.) 



PLATE VII (Pagers). 



SILVER-LEAD. 



Base-bullion smelting. — Yard and roasting stalls of the Colorado Smelter. 



At the left are a pile of coke and a pile of cord wood. Diagonally across the picture 

 is the double line of roasting stalls, from several of which the tops are removed, so that 

 the roasted ore can be taken out ; in the centre of the row is the draft stack, and be- 

 tween the rows runs the tramway. In the background, at the left, the corner of tiie 

 reverberatory roaster house shows; next this is thestack of the shaft furnaces; to the riuht 

 of this are the ore bins, and behind them the shaft furnace house; at the extreme right 

 is the engine house. (Cat. No. 51094, U. S. N. M. From photograph.) 



PLATE VIII (Page 50). 

 SILVER-LEAD. 



Base-bullion HmeUing. — Interior of the shaft furnace house at the tap-hole level, Col- 

 orado Smelter, 



Shows piles of base bullion as cast, slag buggies, and various other tools, the outside 

 of the crucible of the furnace, the slag tap with its water-cooled plate, the iron columns 

 at the corners of the furnace supporting the walls above the crucible, and the bustle 

 pipe, which supplies air to the tuyeres, surrounding the furnace. 



(Cat. No. 51096, U. S. N. M. From photograph.) 



PLATE IX (Page 68). 



LEAD. 



Pig lead and lohite lead smelting combined — General view of the works of the Lone 

 Elm Company, Joplin, Jasper County, Missouri, producing pig lead and white paint 

 by smelting galena and collecting the fumes. 



