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24 hours Altenau amount of silver antimony argentiferous arsenic baryta black copper blast calamine calcined cent of copper cent of lead cent of silver charcoal charge chiefly clay coke consuming copper matt cubic feet cupelling cupelling process cupola furnaces decomposed desilverised dross flue fluxes formation formed Freiberg fuel furnace ends fused galena gold hearth heated impure inches iron pyrites Lautenthal lead containing lead matt lime liquid litharge lixiviation loss of lead loss of metal loss of silver mercury metallic lead metre mixed mixture muffles oxide oxide of lead oxidised Pattinson's process production quantity quartz raw lead raw matt reduced refined residues resulting retorts reverberatory furnaces rich lead roasting mass roasting process schlich silica silver per cwt slags smelting process sodium amalgam speiss sulphate of lead sulphide sulphide of silver sulphuric acid sump temperature treated tuyere u. h. Ztg Upper Hartz volatilisation yield zinc blende
Page 612 - ... situations, the lower hills and valleys are entirely free from them ; frequently a large section of the country will be enclosed from two high ridges capped by deposits, and diverging from a common point; in the intervening space will be seen many secondary ridges, sometimes fifteen or eighteen hundred feet high, formed entirely of the older rocks, no traces of deposits being found on their surface, nor in the ravines that lead from them.
Page 694 - ... the cane or beet root, but to extract only the crystallizable sugar contained in that juice, and to leave whatever else it contains in the cells. To accomplish this purpose, the sugar cane or beet roots are cut into small slices and put into a number of vats, •which are connected by pipes running from the bottom of one vat to the top of the next succeeding. Water of a certain temperature, and of a quantity proportioned to the weight of the cane or beet root in the vats, is mixed with the material...
Page 611 - The stratified rocks of the highest antiquity, such as the oldest gneiss or quartz rocks, have very seldom borne gold : but the sedimentary accumulations which followed, or the Silurian, Devonian, and Carboniferous (particularly the first of these three), have been the deposits which, in the tracts where they have undergone a metamorphosis or change of structure by the...
Page 612 - ... region, in that part of the country which I have examined. They are found in a belt of land from thirty to sixty miles broad, and running parallel with the axis of the range ; and, from facts that I have ascertained from others, I have no doubt but that they exist throughout all the goldbearing region, both north and south.
Page 614 - ... the surrounding rocks. At other points the whole series consists of conglomerates and soft friable sandstone. In the lower strata, quartzose conglomerates, with an argillaceous cement, or loose quartzose gravel, always prevails, with large boulders of quartz, weighing frequently two or three tons, having their surface worn smooth and the angles rounded. The deposits of these heavier rocks have been formed on spots which were evidently lower than the level of the surrounding rocks; whilst on those...
Page 613 - On the top of the hills and the crests of the ridges, where they generally attain their greatest thickness, we find them composed of many distinct strata lying nearly horizontal, and conformable with each other, and generally also with the surface of the underlying rock. In these situations, the most superficial stratum is composed of a mass of extremely hard conglomerate, containing principally trachytic rocks, imbedded in a hard argillaceous cement. It is this hard stratum that has undoubtedly...
Page 611 - T"he stratified rocks of the highest antiquity, such as the oldest gneiss or quartz rocks, have seldom borne gold ; but the sedimentary accumulations which followed, or the Silurian, Devonian, and Carboniferous (particularly the first of these three), have been the deposits which, in the tracts where they have undergone a metamorphosis or change of structure, by the influence of igneous agency or other causes, have been the chief sources whence gold has been derived.
Page 614 - As regards the mineral riches of these deposits, it would appear that gold is found wherever they exist. The ravines coming from the ridges on which they are found are generally extremely rich, and always contain gold, even in places where the deposits themselves have been worked without success. In some places where they have been worked, as much as thirty thousand dollars have been taken from a claim of fifteen feet square ; and there are many instances where tea and fifteen thousand dollars have...
Page 611 - The strike of the beds in that section to which my observations have been confined (between the Stanislaus > and Yuba rivers) is extremely uniform, being from 5° to 10° W. of N. and E. of S. The extent of the diluvial deposits is commensurate, or nearly so, with that of the gold-hearing region, in that part of the country which I have examined.
Page 473 - Before conducting the reader to the nboveground works at the Cornish mines, we must speak of the stream-tin. This kind of ore is disseminated, both in the alluvium which covers the gentle slopes of the hills adjoining the rich tin-lodes, and also in that which fills the valleys that wind round the base of such hills. The most important of these scattered pebbles — for such they may be deemed — are near St Just and St Austell. The works are called stream-works, because flowing water is the chief...