METALS AND THEIR ORES. 1 7 



mercury, still mixed with the tailings, are precipitated or retained by the copper sm-- 

 face of the washer, while the light tailings are carried up by the up current of water 

 produced by the jets of the cone G, and discharged over the edge of the washer F 

 upon the table /, whence they run down into the second washer F', to be treated in 

 the same manner as above. From this second washer the tailings pass into the gut- 

 ter I, the copper lining of which retains the last traces of mercury which may be still 

 mixed with the tailings. 

 What I claim as new, and desire to claim by letters patent, is, — 



1. The arrangement of one or more voltaic piles in the interior of an amalgamating 

 cylinder, substantially as described. 



2. The rod B, extending through the centre of an amalgamating cylinder, and sup- 

 porting the elements of a voltaic pile, in combination with wires a b, one forming a 

 connection between the copper, and the other between the zinc elements of the pile, 

 substantially as set forth. 



3. The arrangement of one or more voltaic cylinders in a receiving-tank communi- 

 cating with an agitating-tub, substantially in the manner shown and described. 



4. The combination, with one or more voltaic cylinders, a receiving-tank, and an 

 agitating-tub of one or more v/ashers, F F', substantially as set forth. 



5. The double-walled hollow inverted cone G, communicating with a water-supply 

 pipe, and provided with jets in its bottom and outer jacket, in combination with a 

 washer, F, constructed substantially as described. 



JULIO H. RAE. 

 Witnesses : 



W. Hauff, 



J. Van Santvoord. 



A gentleman familiar with milling has written the following sketch of 

 the practical working of Rae's process in Virginia: 



The first important difterence between this and the common milling process is, that 

 no water is introduced into the mortars, and the rock to be crushed must be perfectly 

 dry. In all mills the degree of fineness to which the rock is powdered is regulated by 

 a screen, through which alone the pulverized ore finds egress from the mortars. 



In Rae's method, very fine screens are used, so that the rock is reduced to a very 

 minute powder before it escapes from the batteries. It is then carried by an elevating 

 belt to a platform above the battery, where it is emptied into a car large enough to hold 

 one ton of crushed rock. When this amount is received, the car is removed and an- 

 other placed in its stead. The car already charged with the ton of powdered rock is 

 rolled forward till it is above the amalgamating machinery. 



This consists of a large tank so inclined that fluids will readily flow from it through 

 a vent in the lower end. Across this tank, their axis resting on journals supported by 

 its sides, are two cylinders, each seven feet long and four feet eight inches in diameter. 

 VOL. V, 3 



