116 Chronicles of Science. [Jan., 



ings, the observer may employ the bucket as a means of descent, or he 

 may descend by a series of ladders and steps which are placed in 

 various large and irregular openings or cavities which have been pro- 

 duced by the miner in extracting the metal, these cavities are often 

 of large proportions, measuring sometimes 150 feet x 70 feet x 40 

 feet in height, communicating with each other sometimes by narrow 

 passages, and at others by arched galleries cut through the unpro- 

 ductive serpentine. 



" Some portions of the mine are heavily timbered, while in other 

 places columns or arches of rock are left to support the roof. 



" The cinnabar occurs chiefly in two forms, a massive and a sub- 

 crystalline. The first is fine granular, soft and easily reduced to the 

 condition of vermilion ; the other is hard, more distinctly crystalline, 

 compact and difficult to break. It is occasionally seen veining the 

 substance of greenish white or brown compact steatite or serpentine. 

 The ores are extracted by contract, the miners (who are principally 

 Mexicans, being found more adventurous than Cornishmen) receiving 

 a price dependent upon the greater or less facility with which the ore 

 can be broken. The price paid for the harder ores in the poorer parts 

 of the mine is from three dollars to five dollars per cargo of 300 lbs. 

 All the small ores and dirt hoisted from the mine are made into 

 ' adobes,' or sun-dried bricks, for the purpose of building up the 

 mouths of the furnaces in which the quicksilver is separated, to sus- 

 tain the load of richer ores. No flux is used in these furnaces, there 

 being sufficient lime associated with the ores to aid the decomposition 

 of the sulphurets. 



" The furnaces are built of brick, in dimensions capable of holding 

 60,000 to 110,000 pounds, and are fired from a lateral furnace fed with 

 wood ; connected with the furnace is a series of lofty and capacious 

 chambers, through which all the products of combustion are passed, 

 and all the available mercury condensed. Great care is now taken to 

 prevent the escape of mercury through the foundations into the earth 

 Dy building in the brickwork plates of iron, thereby cutting off all 

 descending particles of the metal and turning them inward. 



" Very great discoveries have recently been made at these mines. 

 At one of the new openings a deposit of the richest description of cin- 

 nabar has been discovered, which, so far as hitherto explored, has a 

 linear extent of at least 70 or 80 feet, and in point of richness has 

 never been surpassed by any similar discovery in the past history 

 of the mine. 



" The process of reduction of the mere my is very simple, the time 

 occupied from one charge to another is generally about seven days. 

 The metal begins to rim in from four to six hours after the fires are 

 lighted, and in sixty horns the process is completed. The metal being 

 conducted through the condensing chambers through iron pipes, which 

 discharge into capacious kettles, after which it undergoes no further 

 preparations for the market. 



" The produce of the new Almaden Mines for the last ten years has 

 averaged about 2,500 flasks, of 7(Hlbs. each, of mercury per month. 

 The selling price at San Francisco is, at present, 75 cents per lb., 



