in the form of an open trough, a foot or 15 | in California is assured; there were in the inches in width, and 8 or ten inches deep, State, in the spring of 1868, 472 quartz which are extended to several hundred feet mills carrying a total of 5,120 stamps, and in length. These are set at a suitable slope, nearly all were doing a profitable business. usually about one in twelve, and "riffle" bars There is, of course, a great difference in the are laid across to obstruct the flow of the yield of different veins; some after a period heavy metallic particles which sweep along of great productiveness, coming upon a conthe bottom, while the muddy portions and siderable stretch of barren quartz, where the stones are carried over with a flow of the yield is insufficient to pay expenses, and then water, and discharged at the lower end. passing on to a gangue richer and more proFresh gravel is continually shoveled into ductive than the portion of the vein first the sluices, and once a day, or oftener, these opened. Others will have the precious are cleaned up to collect the gold from the metal in "chutes or "chimneys" scattered riffles and pools, which are sometimes used here and there along the course of the vein, at the head of one joint of the sluice to re- which are enormously productive while the ceive the discharge from the next one above. intervening portions are entirely barren. Where the descent is rapid enough to keep Others still will yield a steady and very unithe pool "in a boil," a considerable portion form percentage, not large but fair. of the gold may be caught in it, especially if general it may be said that quartz mining mercury be introduced. yields a more certain though more moderate success than any other kind of gold mining. In The total production of the mines of California, from the commencement of extensive mining there to the year 1870, was as follows, according to the best authorities : 1848,. 1850,. In 1851, attention began to be turned to the quartz veins, or "ledges," as they were called, and numerous companies were soon established in the United States and in England for carrying on regular mining operations upon these. Within five years after, many deep shafts had been sunk upon veins 1849,. in different parts of the country, and mills wire in operation, furnished with the most efficient machinery for crushing and washing the ore. The uncertain supply of water, and the great expense attending the procuring it by canals from a distance, operated for a time strongly against the success of these works. Upon the Mariposa estate, once the property of Gen. J. C. Fremont, one of the earliest and most extensive ex periments in quartz mining was made. The quartz veins on that estate were not so rich as some which have since been discovered elsewhere, yielding by the old Mexican process with the arasteus only eight or nine dollars to the ton. By a new and improved method, known as the "Eureka Process," the yield was increased to forty or fifty dollars per ton, and from the Princeton mine alone over three million dollars were taken out before 1867. Had this noble property been wisely or well managed, it would have made the General the wealthiest of American millionaires; but, unfortunately, prosecuting his great schemes too rapidly, he fell into the hands of men who stripped him of his grand estate and squandered its profits. But whatever may be the ultimate fate of this great estate, the success of quartz mining 1853, 1851,.. 1855, 1857, 1859,. ... 50,000,000 $945,600,000 The deposits of gold at the mint, and its branches, for the year ending June 30, 1870, were $29,485,263.45. Of silver, for the same time, $3,504,942.51. Total deposits $32,990,210.96. The coinage for the same period was― gold coin, number of pieces, 1,156,087; value, $22,257,312.50; unparted and fine gold bars, $87,846,052.25; silver coin, pieces, 4,649,398; value, $1,767,253.50; silver bars, $902,800.66; nickel, copper, and bronze pieces, 18,154,000; value, $611,445; total number of pieces struck, 23,961,292; total value of coinage, $33,384,863.91. New localities are tested by trying the earth in different places, by washing it in an iron pan or upon a shovel, an experienced hand readily throwing the heavy particles by themselves, while the lighter are allowed to flow away. This method is one of the means in use for collecting gold upon a small scale, and the Mexicans of the gold regions, by long practice, are particularly expert in it. If a vein is to be tested, the quartz is finely crushed, and the powder is then washed in the same manner. Gold may be thus brought to view when none was visible in the stones, however closely examined. By placing a little mercury or quicksilver in the pan, the gold will be more perfectly secured, as, by coming in contact with each other, these metals instantly unite to form a heavy amalgam, and the mercury thus holds the finest particles of gold so that they cannot escape. The mixture, separated from the sand, is squeezed in a piece of thick linen or deerskin, through which the excess of mercury escapes, leaving the amalgam. This may then be heated on a shovel, when the mercury goes off in vapor, and the gold is left in its original-shaped particles, cohering together in a cake. If the quantity of amalgam is considerable, it is distilled in a retort, and the mercury is condensed to be used again. This amalgamation fails entirely if the slightest quantity of any greasy substance is present, as a film of the grease coats every portion of the mercury, and effectually prevents its contact with the gold. These processes contain the principles of nearly all the methods in use for separating gold. great variety of machines have been based upon them, the simplest of which have proved the most valuable. The Burke rocker has always been a favorite machine in the southern states, and has been largely used in California by small companies of miners, and in localities where operations were not carried BURKE ROCKER. A on upon a very extensive scale. It is a cradleshaped trough, about six feet long, set on two rockers, the upper end a few inches higher than the lower, and placed so as to receive at its head a current of water from the end of a leading trough above. This falls upon a perforated iron plate, set as a shelf in the machine, and upon this the auriferous gravel is thrown. The finer particles fall through as the rocker is kept in motion by hand, and the coarse gravel rolls down to the lower end, and falls off upon the ground. Across the bottom of the rocker are placed, at intervals of 6 or 8 inches, low bars or partitions which catch the heavy sands, and prevent their being washed out of the lower end with the water and mud. This lower portion is sometimes arranged as a drawer, which can be secured by a lock, so that the gold which falls into it is safe against robbery. The drawer is called the riffle box." Some rockers are mere open troughs without a shelf. The "tom" is often preferred to the rocker, which it resembles, except in its being a trough without rockers, on the plan of the sluices already described. Both it and the rocker are of convenient size for moving about from one place to another, as the working of the deposit advances. Vein mining requires more efficient machinery, and stamping mills are constructed as near as may be to the mines, for reducing the stony materials to powder, and the sands from the stamps are passed through a variety of machines designed to catch the gold. Stamps are solid blocks of the heaviest cast iron attached to the end of a wooden or iron rod called the leg, to which the lifting cam is applied for raising them. They commonly weigh about 300 lbs. each, though in California they are made of twice and even three times this weight. Several of them are set together in a frame side by side, and are lifted in succession by the cams upon a horizontal shaft, which revolves in front of them. The bed in which they stand, and into which the ore to be crushed is thrown, is sometimes a massive anvil, hollow in the top, firmly imbedded in a heavy stick of timber, or is formed of stones, beaten by the stamps themselves into a solid bed. Water is usually supplied in small currents to the stamps, and sometimes mercury also is poured into the bed. The only exit for the crushed materials is through small holes punched in a sheet of copper, of which the |