Mineralogy and Chemistry

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John P. Morton and Company, 1873 - 401 pages

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Page 334 - ... the body of it presents the form of an irregular, slightly oblique, rhomboidal prism. The upper end, however, is not well defined, but runs up to one side in a flattened protuberance, giving the entire specimen a form approaching roughly an oblique pyramid. The length from the base to the apex is 4£ inches.
Page 152 - The gneissic strata of the tract embracing this group of lead-bearing veins, seem to differ in no essential features from the rest of the formation ranging eastward and westward through this belt of country. Here, as elsewhere, they consist chiefly of soft thinly bedded micaceous gneiss, a more dense and ferruginous hornblendic gneiss, and thirdly a thicker bedded granitic gneiss, composed not unfrequently of little else than the two minerals, quartz and feldspar.
Page 23 - Naxos furnished for several centuries almost exclusively the emery used in the arts, as much from the facility with which it was obtained as for the uniformity of its quality. The emery exists in very great abundance on this island, and notwithstanding the quantity already extracted there still remain immense deposits of it. The price of this substance at the end of the last century was from forty to fifty dollars per ton, and between 1820 and 1835 it was at times even less.
Page 153 - W. ; and what is equally worthy of note, they dip, with scarcely an exception, towards the same quarter, or southeastwardly, though in some instances so steeply as to approach the perpendicular. " There is no marked difference in the general character of the vein-stones of the several mineral lodes, nor any features to distinguish as a class those of the red shale from those of the gneiss.
Page 307 - ... steel in a state of incandescence in a stream of oxygen gas. They were observed on a clear night at different distances ; and the body of light (without the bordering rays) compared with the disk of the moon, then nearly full, at 45 above the horizon.
Page 264 - The mixture was placed in a watch-glass, and spread out so as to expose a large surface to the air; the watch-glass was placed on a support in a copper vessel (the air contained in this vessel could be brought to any required temperature). The experiment being thus disposed, the vessel was heated, and by the time that the air in the interior arrived at 248 Fahr., a change began to take place in the mixture, and at 266 Fahr.
Page 199 - Of course it is not at all remarkable that the potash in the different specimens of leucite should be the same ; but it is a matter of interest to know that from whatsoever locality it comes this minute quantity of rubidium and caesium occurs with it. On some future occasion I hope to be able to bring together certain generalities in this connection of more or less interest to mineralogists. I have also detected rubidium in half a...
Page 152 - A soft, white, and partially decomposed granite is a very frequent associate of the stronger lead-bearing veins, particularly in their more productive portions; but this material belongs, in all probability, not to the ancient granitic injections of the gneiss, but to those much later metalliferous intrusions which filled long parallel rents in that formation with the leadores and their associated minerals.
Page 158 - No analysis was made of this mineral, as it will be embraced in an examination of the American pyromorphites, to be published at some future time. It is found in decomposed granite, on quartz crystals, occasionally covering their entire surface ; in cellular quartz, with molybdate of lead ; in large masses of grouped crystals, with small crystals of yellow and red molybdate inserted on crystals of sulphate...
Page 313 - The time at which it occurred (4 o'clock in the afternoon) rendered the phenomenon of ready observation. The area of observation was about four miles square, and wherever persons were about in that area, the stones were heard hissing in the air, and then striking on the ground or among the trees. Hardly a single person in the immediate vicinity of the occurrence saw any flash or blaze as was noticed by all who heard the report from a distance. Three or four loud reports, like the bursting of bombshells,...

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