TEEATMENT OF THE COMSTOCK OEES. 



219 



have introduced new pans, the characteristic features of which are great 

 capacity and simphcity of construction. Such are the large, flat-bottomed 

 pans of McCone, Horn, and Fountain, which, in their mechanical details, seem 

 to combine some of the best results of the experience that has been gained 

 since pan amalgamation was introduced, and, by their enlarged dimensions, 

 to have the capacity for treating, in the same or nearly the same period of 

 time, a charge three or four times as great as that treated by any of the pans 

 formerly in use. 



In the following pages a few of the pans that have been used, and are still 

 in most favor, will be described briefly but with sufiicient detail to indicate 

 their most characteristic differences. 



Plate XXI presents views of three well-known pans. They show the 

 three different forms of pan-bottoms, the flat, conical, and conoidal. The 

 flat-bottomed pan, Fig. 2, known as Wheeler's Amalgamator, is, perhaps, in 

 more general use than either of the others, although Hepburn and Peterson's 

 pan is in great favor among many mill-men. 



Wheelee's Pan. — The Wlieeler pan of ordinary size is about 4 feet in 

 diameter, at the bottom, and 2 feet, or little more, in depth. The general 

 arrangement of the several parts of the machine may be readily seen by a 

 glance at the drawing. A is the rim of the pan, in the center of which is the 

 hollow cone, B, rising from the bottom, with which it is cast in one piece. 

 Through this cone the vertical shaft, C, passes, which, being driven by the 

 gearing below the pan, gives motion to the muller, D, by means of the driver, 

 E, which is keyed to the shaft, C. The muller is provided, on its under side, 

 with shoes, g, that form the upper grinding surface. The form of the shoes 

 is shown in Fig. 4, on same Plate. They are attached to the muller by means 

 of two lugs or projections, y^J^j which are received in corresponding apertures 

 in the muller-plate and securely wedged with pieces of wood. The lower 

 grinding surface is formed by the dies, i, which are usually four or eight in 

 number, covering the greater portion of the pan-bottom and secured to it in a 

 manner similar to that by which the shoes are fixed to the muller. There is a 

 radial slot or space between the dies which is commonly filled with hard wood. 

 Below the bottom is a steam-chamber for heating the pulp. The vertical 

 shaft or spindle, C, rests in a step-box, h, to which oil is conveyed by the pipe, 



