682 GEOLOGY AXD MIXING IXDCSTEY OF LEADVILLE. 



works. The Fairbanks scales are placed iiuiuediately at tbe entrance of tbe main 

 building and are connected with a small office. The laboratorT occupies a detached 

 construction distinct from the offices. 



Furnaces — There are two blast furnaces, of equal shape, dimensions, and capacity. 

 The capacity of each furnace is 30 tons of ore per 24 hours. Fig 1, Plate XXXI 11, 

 represents the front elevation of one of these furnaces. They are square (S by 7 feet 

 outside measurement at feeding door, and 5 by 5 feet inside measurement of crucible), 

 and their masonry is entirely made of bricks, braced at Q. They are provided with two 

 feed-boles H, opened or closed by means of sliding doors S'. The masonry rests on 

 a main cast-iron plate, 0, supported on four cast-irou-pillars, P. The space /» between 

 tbe masonry and the water-jackets is filled with fire-brick. 



The water-jackets, which are entirely made of cast iron, are similarly disposed 

 in every respect to those of the same kind previously described. They consist of one 

 jacket in front, one at tbe back, and two on each side. They are provided with feeders, 

 outlet-pipes, and supply-pipes. The fire-brick breast V, placed between the hearth 

 and front jacket, is seen in this furnace, and corresponds to a similar arrangement in 

 all square furnaces in which the water-jackets are entirely made of cast iron. The 

 water jackets are provided with seven tuyere-boles, three on each side and one at tbe 

 back, and the furnace is worked with seven tuyeres. 



Patent tuyeres — Fig. 1, Plate XXXIII, was Specially drawn to show the system 

 of tuyeres at this smelter, which ditier in every respect from the thin sheet-iron gal- 

 vanized tuyeres in general use in the camp. Tbe tuyeres were patented December G, 

 187o, by Mr. August Werner. They are made of cast iron, three fourths of au inch 

 thick, and their internal diameter is 2i inches. They are divided into two i)arts, the 

 nozzle X, and the elbow X'. Both the nozzle and tbe elbow are flanged at r, the 

 flanges being faced so as to tit closely and allow no escape of blast. The nozzle and 

 elbow are hinged at d, and to the nozzle are fixed three small chains, c, hooked to the 

 water-jackets. By means of these the direction of the tuyere cau be changed at will 

 so as to send the blast up and down or right and left. At this end the nozzle termi- 

 nates in a wrought-iron spherical i ing or ball, which works freely in a socket of tbe same 

 metal, wedged in the tuyere-hole of the water-jacket. In other words, tbe tuyere works 

 in a ball-and-socket joint. To stop tbe blast in any point of tbe furnace or to observe 

 what is going on there, the elbow is litted, as indicated in Fig. 1. Tbe tuyeres are con- 

 nected, as usual, with the blast-pipes by means of canvas wind-bags K. When the 

 blast is turned off for the purpose of barring down tbe accretions of tbe furnace or 

 clearing the hearth of accretions, a piece of paper is inserted between the flanges r, and 

 should back flow of gases exert any pressure in the furnace the piece of paper would 

 burst, the elbow of tbe tuyere be lifted, and tbe tuyere would thus act as a safety- 

 valve. But this accident, so far as known, has never occurred in Leadville. 



The normal pressure of blast used at these works is seven-eighths of an inch 

 mi-rcury. The crucible of the furnace is provided with a projecting fore-hearth and 

 lead siphon-tap and is lined with fire-brick. 



Dust-chambers. — The apparatus devised for the condensation of lead fumes at 

 smelter F is the most elaborate of its kind used in Leadville, and is certainly the most 

 efficient. Each furnace is connected with a separate condenser, placed above the 

 feeding floor, and is identical with tbe one shown in side and front elevation, Plate 

 XXXI V. 



