Observations on mineral veins

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Printed by J. Trathan, 1837 - Science - 65 pages
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Page 52 - Ixjcome insoluble, may, in many instances, have interfered with the regular arrangement of the metals, such as electricity would have effected ; and that hence, many anomalies may have arisen, especially in relation to tin. 11. That the electrical reaction of the different metalliferous bodies, and of masses of ore on each other, after their deposition in the fissures, may have corrected such anomalies in some instances, and that they may have given rise to them in others, by changing the direction...
Page 20 - IK- north, and vice versa. Some veins are quite irregular, or zigzag in their underlie. When two neighbouring metallic veins run in an oblique direction, and meet, they commonly produce a body of ore at the place where they cross, either horizontally, or in their dip, if both contain ore ; but if one be poor, and the other rich, they are either united, or are both impoverished at their meeting : in the former case they generally separate again after a time, and continue their original course. When...
Page 51 - ... have been decomposed by the agency of such electric currents, and the bases been thereby determined, in most instances, towards the electro-negative pole or rock : that tin, however, under these circumstances, is only partly deposited at the electro-negative pole, and partly at the electro-positive pole, in the state of a peroxide ; and that these properties of this metal seem to bear on its positions in the lodes, with regard to copper, being sometimes found with it, and sometimes distinctly...
Page 37 - ... sulphur, and probably, also of some of the iron which it contained ; and beautiful crystals of pure copper, were abundantly deposited upon it, and likewise, in some instances, red oxide of copper. - These experiments seem to bear on the fact of neither metallic, nor red oxide of copper, occuring in our mines in conjunction with yellow copper ore, but often with the sulphuret, or grey and black ore. When a solution of sulphate of iron...
Page 51 - ... superior degree to the rocks themselves ; it is evident, that in conformity with the laws of electro-magnetism, the currents of electricity would, if not otherwise controlled, pass towards the. west, through such fissures as were most nearly at right angles to the magnetic meridian at the time. 8. That the more soluble, metallic, and earthy salts, may have been decomposed by the agency of such electric currents, and the bases been thereby determined, in most instances, towards the electro-negative...
Page 64 - ... successful. The advantages it possesses over the ordinary balance are extreme sensibility, it being capable of indicating much less than the ten thousandth part of a grain ; the facility with which its indications are obtained; and the comparatively low price at which it can be rendered. To adjust the instrument for use, it must be carefully levelled by the screws, two of which are shown at g and h ; the beam is then brought to the zero points by turning the magnets, and when ascertained to be...
Page 50 - I have, amongst other things, endeavoured to show :— 1. That admitting the origin of mineral veins to have been derived from fissures in the earth, there is reason to believe that the latter may have been produced by different causes, and at various intervals ; also that many of them have been enlarged from time to time. 2. That the accumulation of mineral ' deposits in such fissures has...
Page 51 - ... were calculated to produce electrical action ; and that this action was probably much increased, by the circulation of the water, and differences of temperature; but more particularly by the existence of compressed and heated water, metallic bodies, &c., at or near the bottom of the fissures. 7. That since the. water in the fissures containing metallic, or. earthy salts, was a conductor of electricity, especially when heated,, and in a very superior degree to the rocks themselves ; it is evident,...
Page 51 - ... temperature, it is obvious that it would tend to dissolve some substances at a great depth, which it would deposit, more or less, in the course of its ascent through cooler portions of water ; and also in consequence of its partial evaporation on reaching the surface. 5. That a part of the earthy contents of veins, and more especially silica or quartz, was apparently accumulated in this manner, and usually combined, more or less, with matter otherwise deposited. , 6. That rocks, clay, &c., containing...
Page 11 - ... than usual, in their composition. The quartz in the cross courses is very peculiar in its crystalline Structure, having. a fibrous, striated, or radiated appearance, with the axes of the crystals, when not much radiated, nearly at right angles to the direction of the sides of the veins. This quartz the miners term ucwm course spar...

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