Mineralogy and Crystallography: Being a Classification of Crystals: According to Their Form; and an Arrangement of Minerals, After Their Chemical CompositionR. Griffin and Company, 1860 - 298 pages |
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Mineralogy and Crystallography: Being a Classification of Crystals According ... James Tennant,Walter Mitchell No preview available - 2016 |
Common terms and phrases
A₁ angular element Augite axis B₁ B₂ Baryte basal pinacoids Bohemia Bournonite Brittle Brooke and Levy brown Calcite Cerussite Chalybite Chessylite circle of latitude colourless conchoidal copper Cornwall crystals cubical axes cuts Decomposed by hydrochloric derived double four-faced pyramid draw edges Faces parallel Felspar four-faced cube four-faced solid angles Frac fusible G₁ G₂ gray green H₂ Hartz Hematite hemihedral forms hexagonal prism Hungary hydrochloric acid infusible inscribed iron Join latitude Levy's longitude M₁ M₂ metallic Miller mineral Naumann nitric acid Norway O₁ oblique octahedral axes octahedron Opaque P₁ P₁ P₂ planes Polar distance poles prismatic Pyrargyrite Pyrite Quartz R₁ rhombic axes rhombic dodecahedron Rhombic Prism rhombohedral rhomboid Saxony scalenohedron Sectile Siberia six-faced octahedron six-faced solid angles solid angles Soluble in nitric Spar sphere of projection sulphuric tetrahedron three-faced solid angles translucent Transparent trapezohedron triangle twelve-faced Tyrol uneven vitreous yellow
Popular passages
Page 479 - Fig. 10 ; lay the plate on the table with the edge, /, parallel to the window, the side to which the wax is attached being uppermost, and press the end of the wax against the crystal until it adheres ; then lift the plate with its attached crystal, and place it in the slit of the pin, x, with that side uppermost which rested on the table.
Page 480 - ... on its axis, to bring the reflected image of the bar of the window to coincide accurately with the line below, now move the lower end of the pin laterally, either towards or from the instrument, in order to make the image of the same bar, reflected from the second plane, coincide with the same line below. " Having ascertained by repeatedly looking at, and adjusting both planes, that the image of the horizontal bar, reflected successively from each...
Page 480 - ... of the small minute fragment which is to be measured. This position on the instrument ought also to be attended to when the fragments of crystal are large. In which case the common edge of the two planes, whose inclination is required, should be brought very nearly to coincide with the axis...
Page 469 - ... and therefore if, from a single * "A twin-crystal is composed of two crystals joined together in such a manner " that one would come into the position of the other by revolving through two right " angles round an axis which is perpendicular to a plane which either is, or may be, " a face of either crystal. The axis will be called the twin-axis, and the plane to " which it is perpendicular the twin-plane." Miller's Treatiie on Crystallography, p. 103. In the text the word
Page 480 - Turn the pin, x, on its own axis also, if necessary, until the reflected image of the bar of the window coincides accurately with the observed line below the window. " Turn now the small circular...
Page 479 - ... uppermost which rested on the table. " Bring the eye now so near the crystal, as. without perceiving the crystal itself, to permit the images of objects reflected from its planes to be...
Page 291 - If as much common salt be thrown into boiling water as it will dissolve, beautiful cubes wШ be seen to form rapidly on its surface as it cools, as well as on the sides of the vessel in which it is contained. The same thing will occur more slowly, if a saturated solution of salt in cold water be allowed to evaporate spontaneously. A warm solution of alum will deposit...
Page 482 - To learn to distinguish minerals by their color, weight and luster, is so far very well; but the accomplishment is of a low degree of merit, and when most perfect makes but a poor mineralogist. But when the science is viewed in the light of Chemistry and Crystallography, it becomes a branch of knowledge, perfect in itself, and surprisingly beautiful in its exhibitions of truth. We are no longer dealing with pebbles of pretty shapes and tints, but with...
Page 353 - They were suggested to the ancients by their believing that these bodies were endowed with mysterious properties, on which the explanation of the most eecret phenomena of nature depended.
Page 479 - ... ten or twelve feet from a flat window. The graduated circular plate should stand perpendicularly from the window, the pin x being horizontal, not in the direction of the axis, as it is usually figured, but with the slit end nearest to the eye. " Place the crystal which is to be measured on...