682 GEOLOGY AND MINING INDUSTRY OF LEADV1LLE. 



works. The Fairbanks scales are placed immediately at the eutrauce of the main 

 building and are connected with a small office. The laboratory 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 Lours. Fig 1, Plate XXX11I, 

 represents the front elevation of one of these furnaces. They are square (8 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-holes 17, opened or closed by means of sliding doors S'. The masonry rests ou 

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

 the 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 the 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-holes, three ou each side and one at the 

 back, and the furnace is worked with seven tuyeres. 



Patent tuyeres Fig. J, Plate XXXIII, was specially drawn to show the system 

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

 vanized tuyeres in general use in the camp. The tuyeres were patented December 6, 

 1875, by Mr. August Werner. They are made of cast iron, three fourths of an inch 

 thick, and their internal diameter is 2J inches. They are divided into two parts, the 

 nozzle N, and the elbow JV'. Both the nozzle and the 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 <7, and to the nozzle are fixed three small chains, c, hooked to the 

 water-jackets. By means of these the direction of the tuyere can 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 the same 

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

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

 what is going on there, the elbow is lifted, as indicated in Fig. 1. The 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 the accretions of the 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 thfe piece of paper would 

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

 valv*. 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 

 nu-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 the one shown in side and front elevation, Plate 

 XXXIV. 



