Now, in regard to the auriferous quartz veins, it is the result of past experience that they are often rich in the upper part, but become poorer as the explorations are deepened, and soon cease to pay the expense of working. In this respect it is just possible that the Californian veins may not agree with those of the Ural and of other regions, though this is a point which the lapse of years only can settle. Two things, however, are in favour of the greater yield of the Californian veins than those of other countries in past times—that they will be explored by a people who abound in capital, in engineering skill, and in energy, and that it is now ascertained that veins may be profitably rich in gold, though the particles are too small to be discerned by the naked eye. Thus, while all the explorations will be made with skill and economy, many veins will be mined into, which in other countries have been passed over with neglect; and the extraction of gold from all—but especially from the poorer sands and veins—will be aided by the second circumstance to which we have adverted as peculiar to California, the possession of vast stores of quicksilver. “The most important, if not the most valuable, of the mineral products of this wonderful country, is its quicksilver. The localities of several mines of this metal are already known, but the richest yet discovered is the one called Forbes’s mines, about sixty miles from San Francisco, near San José. Originally discovered and _denounced_, according to the Mexican laws then in force, it fell under the commercial management of Forbes of Tepic, who also has some interest in it. The original owner of the property on which it is situated, endeavoured to set aside the validity of the denouncement; but whether on tenable grounds or otherwise, I know not. At this mine, by the employment of a small number of labourers, and two common iron kettles for smelting, they have already sold quicksilver to the amount of 200,000 dollars, and have now some two hundred tons of ore awaiting the smelting process. The cinnabar is said to yield from sixty to eighty per cent of pure metal, and there is no doubt that its average product reaches fifty per cent. The effect of these immensely rich deposits of quicksilver, upon the wealth and commerce of the world, can scarcely be too highly estimated, provided they are kept from the clutches of the great monopolists. Not only will its present usefulness in the arts be indefinitely extended and increased by new discoveries of science, but the extensive mines of gold and silver in Mexico, Chili, and Peru, hitherto unproductive, will now be made available by its application.”—(JOHNSON’S _Sights in the Gold Region_, p. 201.)