On the Microscopical Structure of Crystals: Indicating the Origin of Minerals and RocksTaylor & Francis, 1858 - 48 Seiten |
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On the Microscopical Structure of Crystals: Indicating the Origin of ... Henry Clifton Sorby Keine Leseprobe verfügbar - 2014 |
On the Microscopical Structure of Crystals: Indicating the Origin of ... Henry Clifton Sorby Keine Leseprobe verfügbar - 2018 |
Häufige Begriffe und Wortgruppen
action of water alum ammonia amount aqueous solution artificial crystals augite bichromate of potash block ejected bubbles calcite calculated Canada balsam chloride of potassium chloride of sodium common salt compression cooling Cornwall crystalline crystals formed deduced deposited from solution depth difference dull red heat ejected from Vesuvius elastic force elvans and granites enclosed equation erupted lavas excellent fluid-cavities fact feet of rock felspar Fluid-cavities in chloride formed at 100 gas-cavities glass glass-cavities Gwennap high temperature highly heated idocrase igneous fusion inch indicate leucite metamorphic rocks mica microscopical structure Minerals and Rocks nearly nepheline occur ordinary temperature pitchstone porphyritic portion potash prismatic crystals probably pyroxene quartz of granite red heat relative saline solutions schorl seen shown by fig slags small crystals sodium formed solid crystal solution in water stone-cavities STRUCTURE OF CRYSTALS substance sulphates temperature tion trachyte of Ponza Trevalgan tubes vacuities vapour of water vapour-cavities veins volcanic whilst
Beliebte Passagen
Seite 45 - I cannot but make a few remarks in conclusion on the value of that instrument, and of the most accurate physics in the study of physical geology. Although with a firstrate microscope, having an achromatic condenser, the structure of such crystals and sections of rocks and minerals as I have prepared for myself with very great care can be seen by good day-light as distinctly as if visible to the naked eye, still some geologists, only accustomed to examine large masses in the field, may perhaps be...
Seite 13 - ... formed in water. It is simply the deposition of crystals from solution in a liquid that becomes solid at a high temperature, or the crystallization of that liquid itself, in the same manner as when crystals are deposited from solution in water, or the water itself freezes. Nevertheless the temperature at which water and melted rocks become solid are so very different, that the two processes may be conveniently classed under different heads. It is quite inaccurate to suppose that the presence...
Seite 45 - ... calculations from such small data are quite inadmissible. What other science, however, has prospered by adopting such a creed? What physiologist would think of ignoring all the invaluable discoveries that have been made in his science with the microscope, merely because the objects are minute? What would become of astronomy if everything was stripped from it that could not be deduced by rough calculation from observations made without telescopes? With such striking examples before us, shall we...
Seite 38 - ... energetic, I cannot think that its influence was unimportant. On the contrary, seeing that the fluid-cavities in the quartz of quartz-veins contain the selfsame salts and acids as those in the granite, as though it had been deposited from portions of the liquid which had passed from the granite up fissures, I think the amount, though limited, must nevertheless have been considerable, and that its presence will serve to account for the connexion between granite and quartz-veins, and the very intimate...
Seite 13 - A glass is a liquid which, on cooling, becomes more and more viscous, and at length solidifies without undergoing any sudden and definite change in physical structure. If, however, the liquid, after cooling to a certain temperature, crystallize, it undergoes a sudden and entire physical change, and the structure becomes stony. In most cases the crystals thus formed possess double refraction, and therefore depolarize polarized light ; whereas the uncrystalline glass has no more influence on it than...
Seite 45 - I have described, and to think the objects so minute as to be quite heneath their notice, and that all attempts at accurate calculations from such small data are quite inadmissible. What other science, however, has prospered by adopting such a creed ? What physiologist would think of ignoring all the invaluable discoveries that have been made in his science with the microscope, merely because the objects are minute ? What would become of astronomy if everything was stripped from it that could not...
Seite 42 - ... 203 53,900 Granite from the Ding Dong Mine, near Penzance, . . 162 63,600 Mean of the Highland porphyry-dykes, 135 69,000 Exterior of the main mass of the granite at Aberdeen, . 135 69,000 Mean of the Highland granites, 99 76,000 Centre of the main mass of the granite at Aberdeen,. . 89 78,000 " It will thus easily be seen that, if pressure is not taken into account, there is a gradual decrease in temperature on passing from trachyte to granite ; whilst if, as is far more probable, the temperature...
Seite 45 - ... quartz veins, having a structure precisely analogous to that of crystals deposited from water. Between these there is every connecting link, and the central link is granite. When the water intimately associated with the melted rock at great depths was given off as vapour whilst the rock remained fused, the structure is analogous to that of furnace slags. If, however, the pressure was so great that the water could not escape as vapour, it passed as a highly heated liquid holding different materials...
Seite 19 - ... communication I shall illustrate the subject by applying them to some of the leading branches of inquiry, without attempting to treat each in a complete manner. By many experiments, I have proved most conclusively that the fluid in the cavities in the quartz of granites and elvans is water, holding in solution the chlorides of potassium and sodium, the sulphates of potash, soda, and lime, sometimes one, and sometimes the other salt predominating.
Seite 48 - ... schorl. X1200. Fig. 112. A fluid-cavity in the felspar of the granite at Penrhyn, Cornwall. X1600. Fig. 111. A portion of the quartz of the granite at St. Austel, Cornwall, X 200, with many fluid-cavities, and one vapour- or gas-cavity. Fig. 113. A fluid-cavity in the mica of a granite-vein at Polmear Cove, Cornwall. X1600. Figs. 114, 115. Fluid-cavities in the quartz of the granite from the Ding Dong Mine, near Penzancc.