MINING. 287 



mining captains to observe these veins closely, and trace them 

 np when a "fault" occurs. There are no scientific rules for 

 finding the ore ; and the business of searching for the large 

 deposits is never intrusted to educated mining engineers, but 

 ahviiys to mining captains, who have themselves been laborers, 

 and have learned by experience where to seek. The New 

 Almaden mine produces two hundred and twenty thousand 

 pounds of metal in a month. The hacienda^ or reducing estab- 

 lishment of the mining company, has fourteen brick furnaces, 

 each fifty feet long, twelve feet high, and twelve feet wide. At 

 one end of each furnace is the fire chamber, which maybe nine 

 cubic feet inside ; next that is the ore chamber of about the 

 same size ; and beyond that is the condensing chamber in 

 which there are a number of partitions alternately running up 

 from the bottom and down from the top, with a space for the 

 fumes to pass, their course being up and down, and up and 

 down again, and so on, for a distance of thirty feet to the 

 chimney, which is forty feet high. In the bottom of the con- 

 densing chamber is water. The walls between the fire cham- 

 ber and the ore chamber, and between the latter and the con- 

 densing chamber, are built with open spaces, so that the heat, 

 smoke, and fumes can pass through. The ore is placed in the 

 ore chamber in such a manner as to leave many open spaces. 

 The heat drives off the sulphur and mercury of the ore in 

 fumes, which in passing through the condensing chambers, de- 

 posit the mercury, and the smoke and sulphur escape through 

 the chimney. In the Enriqueta and Guadalupe mines the 

 quicksilver is condensed in a close iron retort, and the sulphur 

 is absorbed by quicklime. 



Copper ore is dug from several mines in California, but it is 

 all exported to be smelted elsewhere. 



§ 216. Platinum. — Platinum, iridium, and osmium, three 

 white metals of about the same specific gravity with gold, are 

 found with the latter metal in the placers in the basin of 

 the Klamath and Trinity Rivers. Their particles are usually 

 fine scales, very rarely reaching a quarter of an ounce in weight, 



