676 GEOLOGY AND MINING INDUSTRY OF LEADVILLE. 



Furnaces — Smelter C has three furnaces of equal dimensions and capacities, con- 

 structed on the plan of Messrs. Keyes & Areut's patent. At the time this report 

 ■was made, however, only two furnaces were running, and all that has been said or 

 will be said of this smelter refers to the work done by the two furnaces. 



They may be considered the model furnaces of Leadville, both as regards appear- 

 ance and working qualities, and will therefore be described in considerable detail. 

 One of them is represented on Plate XXIX, in elevation (Fig. 1), transverse and longi- 

 tudinal sections (Figs. 2 and 3). The crucible A of this furnace differs essentially from 

 nearly all the others used in Leadville in that the lead well L does not project out- 

 sideof the crucible frame, but, together with the crucible, is coufiued within the frame 

 formed by the hearth-plates. A glance at this furnace and at any of the others, with 

 exception of the furnuce shown in Plate XXXII, will show the diflerence. Another 

 peculiarity is that lead is not ladled out of the lead-well, as at other smelters, but a 

 tap hole, s', is made in its clay lining, and the bullion is drawn periodically into the 

 cast-iron lead pot T, mounted on a small cast-iron stove, in which a slow fire is placed 

 in order to keep the bullion molten. The chimney / of this stove communicates 

 under ground with the dust-chamber. The advantage of this disposition is twofold : 

 the lead-well may remain constantly covered and its bullion be kept at a high tem- 

 perature, thus assisting the clearing of the siphou when this is necessary. On the 

 other hand, the bullion accumulating in the lead-pot, being kept molten, can be ladled 

 rapidly into the molds, and the bars thus obtained are of a good shape and uniform 

 composition. The entire hearth rests on a bed-plate of boiler-iron, with an angle-iron 

 rim, which incloses the base of the bearth-walls or lining of the crucible. These walls 

 X are entirely of fire-brick, but the dam of the crucible A" is protected by tami)ing 

 or pressed fire-clay, as are the siphon L' and tlie lead-well L. The bottom of the 

 crucible is formed by an inverted fire-brick arch, with quartz-brasque beneath, sepa- 

 rating it from the bed i)late. 



The hearth is inclosed on the sides by four cast iron plates, a, each 1 inch thick, 

 of which the front and back ones have each 2 inch flanges lapping over the ends of the 

 side plates. These plates are firmly held together or inclosed by three rows of bars 

 or rails, Q', which are fa.steued at each corner by wrought-iion rings j). The top of 

 the h(jarth is also C3vered by iron plates, d. To the front hearth-plate is screwed and 

 bolted the slag gutter or spout U, and to the side plate the lead-gutter, U', leading 

 from the lead-tap ~. 



These are the only furnaces in which the fore-hearth does not project outside of 

 the frame of the heurth. The crucible, though constructed on the same general prin- 

 ciples as those of other furnaces in Leadville, differs essentially in the arrangement of 

 details. 



The water-jackets are thirteen in number, one in front, two at the back, and five on 

 each side. They are screwed together and wedged at q, and braced by tie-rods; the tie- 

 rods under the hot-water outlets ^are not indicated on the drawing. The front water- 

 jacket does not extend down to the bearth-jdate, but rests on a fire-brick wall, in the 

 middle of which is a .small water-cooled cinder-block inclosing the slag-hole (see Fig. 

 2), instead of the ordinary tympstone shown in Fig. 1, Plate XXXIII. 



The wa'.er jackets are otherwise similar in construction and appearance to those 

 alreadv described. Cold water is brought by the pipe iU, and passes through short 



