A Summary of Progress in Petrography. in 1887-1896 |
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Page 12
... symmetry becomes a : b : c = .5744 : 1 : 5425 , and the forms oP , ∞ P∞ , ∞ P ' , ∞ ' P , P ' , ' P , P1 , ‚ P , † P'3 , † P. 3 . Mineral Syntheses . - Boracite has been produced by Gramont in the wet way . One part of borax and two ...
... symmetry becomes a : b : c = .5744 : 1 : 5425 , and the forms oP , ∞ P∞ , ∞ P ' , ∞ ' P , P ' , ' P , P1 , ‚ P , † P'3 , † P. 3 . Mineral Syntheses . - Boracite has been produced by Gramont in the wet way . One part of borax and two ...
Page 13
... symmetry of higher grade than that be- longing to its individual constituents . Martin has examined several organic compounds , and is thereby led to the conclusion that in these the anomalies are due to strain or pressure exerted on ...
... symmetry of higher grade than that be- longing to its individual constituents . Martin has examined several organic compounds , and is thereby led to the conclusion that in these the anomalies are due to strain or pressure exerted on ...
Page 14
... symmetry of the figures obtained indicate a tetragonal symmetry for the mineral . Anomalous figures on some crystals , found only on planes that show double refraction , are explained as due to the manner of growth . Many new ideas are ...
... symmetry of the figures obtained indicate a tetragonal symmetry for the mineral . Anomalous figures on some crystals , found only on planes that show double refraction , are explained as due to the manner of growth . Many new ideas are ...
Page 14
... symmetry with the faces on which they occur , with the exception of those on the brachypinacoid 2P , which are unsymmetrical . According to Pelikan 19 they resemble the figures produced by Baumhauer upon treating the mineral with molten ...
... symmetry with the faces on which they occur , with the exception of those on the brachypinacoid 2P , which are unsymmetrical . According to Pelikan 19 they resemble the figures produced by Baumhauer upon treating the mineral with molten ...
Page 19
... symmetry . of these is assumed as the base , and the other as the orthopinacoid , when the axial ratio becomes a : b : c = 2.1937 : 1 : 1.73385 ; ß = 80 ° 12 ' . The forms observed are ∞ P∞ , ∞P , -P , P , Poo , and -3P3 . Hardness ...
... symmetry . of these is assumed as the base , and the other as the orthopinacoid , when the axial ratio becomes a : b : c = 2.1937 : 1 : 1.73385 ; ß = 80 ° 12 ' . The forms observed are ∞ P∞ , ∞P , -P , P , Poo , and -3P3 . Hardness ...
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Common terms and phrases
acid Al,O alteration Amer AMERICAN NATURALIST analysis andalusite angle aragonite augite axial ratio basalts beryl biotite brucite Bull calcite calcium chlorite cleavage Colby University color colorless composition constituents containing cordierite corresponding crystalline crystals density described diabase double refraction dyke eruptive rocks Fe,O Fe₂O feldspar FeO MgO CaO FeO MnO forms formula Franc gabbro-diorites gabbros garnet Genth gneisses granite granulites ground-mass H₂O habit hexagonal hornblende humite hypersthene imbedded inclusions Jour Kryst leucite masses melanophlogite metacinnabarite mica mineral MINERALOGY AND PETROGRAPHY.¹ Mitth molecules muscovite Neues Jahrb nosean occur olivine optical original orthoclase ottrelite parallel Penfield Petrog PETROGRAPHY.¹ Petrographical phenacite plagioclase plane plates polymorphism prismatic produced pseudomorphs pyroxene quartz regarded rock individual Rosenbusch schistose schists serpentine silica sodium soluble specific gravity specimens spinel structure substance sulphur symmetry tabular temperature tonalite tourmaline twinned varieties W. S. Bayley Waterville yielded Zeits zircon zone
Popular passages
Page 19 - The plane of the optical axes is perpendicular to the plane of symmetry, and makes with c an angle of °7 in acute /9. A = b. 2H na = 104° 27'.
Page 14 - The larger part of the dust is thought to be a sediment from the air, and to have been obtained by it from a region of crystalline schists. The chondri, on the other hand, are thought to be of cosmic origin, since they are similar to the chondri obtained in deep-sea soundings. If the amount of the dust collected from the snow in Greenland represents the fall of one year, the total amount falling upon the entire surface of the earth in this time is 125 million kilograms, equivalent to a cube of thirty-one...
Page 14 - Wiilfing 21 for investigation, by whom it has been found to consist in greater part of feldspar, quartz, mica, and hornblende. There are present in it also garnet, zircon, magnetite, augite, and sillimanite, and with them is mixed a nitrogenous organic substance. The most interesting constituents of the dust...