TEEATMENT OF THE COMSTOCK OEES. 203 



silver as possible, is then subjected to the process of sublimation, by which 

 means the quicksilver is separated from the gold and silver. This is 

 effected in a cast-iron retort. The retorts in use are of various forms, 

 but the most-approved is cylindrical, about 12 inches in diameter inside, 

 and from 3 to 5 feet long ; the casting being an inch and a half thick. 

 (See Figs. 1 and 2, Plate XVIII.) The open end of the retort, or the 

 end by w^hich the charge is introduced, is cast vv^ith a flange or hood into 

 which the door or cover of the retort is fitted. Within the cylindric por- 

 tion of this flange or hood are two inclined lugs, opposite each other. A 

 bar or bale, turning upon a pin in the center of the door, holds it firmly 

 in its place by the ends of the bar being turned under the inclined lugs. 

 When charged, the joint between the door and the bottom of the flange 

 is made tight by means of clay luting. Another method of securing the 

 door is shown in Fig. 9, Plate XVIII. The opposite end of the retort is 

 usually made conoidal in form. In such case the main cylindrical portion, 

 12 inches in diameter, is 3 feet long, at which point the diameter of the con- 

 oidal neck is gradually diminished to 2^ inches at the extreme end of the re- 

 tort, from which the exhaust pipe, h, the purpose of which is to afford escape to 

 the volatilized quicksilver, turns downward and passes through the condenser, 

 the construction of which is shown in Fig. 3. This is usually arranged on the 

 principle of the Liebig condenser and consists of a pipe, a, of considerably 

 larger diameter than the exhaust pipe, h, so that the latter may pass entirely 

 through the former, which, when in use, is kept constantly supplied with 

 cold water by a pipe, d, opening into the bottom, the heated water flowing oflf 

 at the outlet, e, near the top. The quicksilver condensing in the exhaust- 

 pipe falls into a receiver, placed under the end of the pipe, and which is also 

 nearly full of water. The end of the exhaust pipe dips below^ the surface 

 of the water to prevent access of air but not sufficiently to permit the pas- 

 sage of the water into the heated retort under any circumstances. 



The retort is set in a brick furnace of simple construction, sometimes 

 supported by a brick arch, through which a number of flues permit the pas- 

 sage of the heat from the fire-place below, sometimes resting on cross-bars of 

 iron, the ends of which are fixed in the brick sides of the furnace, as shown in 

 Fig. 1, Plate XVIII. Directly below the retort, extending under its whole 



