610 Transactions of the American Institute. 



minutes' walk from the Yellow Jacket, with which, however, I believe 

 it has no business connection. The ore, broken to about the average 

 size of paving stones, but of angular and irregular form, lay in a heap 

 as it had come from the mine. Two Chinamen, with long-handled 

 hammers, were breaking it to an egg size ; this being about the only 

 kind of labor to which, in the manipulation of the ore, the almond- 

 eyed foreigners are found adapted, as the underground work is too 

 severe for them. The broken rock is thrown into the mill, which, in 

 this case, had ten stamps. The stamps are simply iron pestles fitted 

 on the lower ends of vertically-moving shafts, which have collars up on 

 them, under which move cams provided on a transverse shaft. The 

 rotation of the last causes the cams to lift the stamps a certain dis- 

 tance, and then, the cams slipping past the collars, let the stamps 

 descend upon the material placed in a strong rectangular receptacle, 

 or, so to speak, a mortar arranged underneath. A stream of water 

 enters the mortar at one side, and flows out at the other through a 

 sieve. This sieve retains the coarsely-broken rock in position under 

 the stamps, but allows the finer particles to be carried out continually 

 by the water into a shallow tank. Here the floured ore sinks to the 

 bottom as a muddy sediment, which is transferred, mingled with a 

 quantity of water, to the amalgamator. This is an iron mill, the lower 

 plate or grinding surface of which is stationary, while the upper one 

 revolves, inclined blades or guides being so arranged within the sur- 

 rounding case that, as the semi-fluid mass is thrown outward from 

 between the edges of the two plates, it is swirled back over the upper- 

 most, and passes down through an opening in its center to be subjected 

 to a repetition of the operation. After about five hours of this treat- 

 ment, the mass is ready for the quicksilver, which is added in the 

 proportion of 200 pounds to five tons of ore. The grinding is con- 

 tinued for a couple of hours longer, by which time it is assumed that 

 the amalgamation, otherwise the combination of the silver with the 

 quicksilver, is well-nigh complete. The contents of the grinders are 

 then transferred to what are called " settlers," circular tanks with 

 revolving mullers inside similar to the grinding devices of the preced- 

 ing apparatus. The muller keeps the mass in constant agitation, dur- 

 ing which the amalgam, together with the uncombined mercury, sinks 

 to the bottom, whence both are drawn off by a siphon, and then placed 

 in a long and narrow wash-leather sack. By applying pressure to this 

 sack the free mercury is strained out, and the remaining amalgam, 

 having about the consistence of putty, but with less coherence and an 

 unctuous feel, is transferred to the retorting apparatus. This is a 



