228 MINING INDUSTEY. 



inequality of wear. These spaces in some of the Fountain pans, are filled 

 with wood, as already described in pans of other makers. The shoes at their 

 circumferential edge are provided with plows to stir up the quicksilver lying 

 on the pan-bottom. These pans work 3,000 or 4,000 pounds of sand at a 

 single charge. Their average duty, in working tailings, is stated at ten tons 

 per day. 



Settlers or Separators. — The settlers or separators (see Plate XVII) 

 in which the quicksilver and amalgam are allowed to settle or separate 

 themselves from the pulp, after treatment in the pan, have already been 

 generally described on a foregoing page. They do not present so many 

 important difFerences in details of construction as the pans do. They are 

 made larger than the pans, usually having a diameter of 7 or 8 feet. They 

 are commonly made now with a flat, sometimes concave, circular, cast-iron 

 bottom, having a hollow cone or pillar at the center and a flange at the 

 circumference, to which the rim, either of wood or sheet-iron, is attached. 

 The central shaft, with its driving gear below, the screw and nut arrange- 

 ment above, for raising and lowering the stirrers, and the yoke or driver fitted 

 to the revolving shaft, are not essentially different from the similar parts of 

 the pans. Hangers are sometimes bolted to the bottom of the settler to 

 carry the step-box of the vertical shaft and support the driving gear; or these 

 may rest on a timber frame independent of the bottom, as shown in the figure 

 on Plate XVII. To the yoke or driver are attached four radial arms reaching 

 to the circumference of the vessel. On each arm are two or sometimes three 

 legs, terminating in a wooden shoe, variously shaped, which touches the bot- 

 tom, These legs are movable radially, so that any one may be fixed at such 

 point between the center and circumference as may be desired, and they are 

 usually arranged at diflferent distances on the several arms, so that in the course 

 of each revolution each part of the surface of the bottom is passed over by 

 one or another of the shoes. 



The discharge of the separator is usually effected through outlet-holes, 

 already described, and shown in Fig. 1, on Plate XVII, Sometimes, as in a 

 separator constructed by Mr. Fountain, the discharge holes are placed in the 

 central cone of the vessel, in order that it may be where there is the least 



