Elements of Optical Mineralogy: Principles and methods

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John Wiley & sons, Incorporated, 1922
 

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Page 28 - For convenience all minerals are referred to a scale of hardness of ten units, composed of common or well known minerals, which are as follows: (1) talc; (2) gypsum; (3) calcite; (4) fluorite; (5) apatite; (6) orthoclase; (7) quartz; (8) topaz; (9) sapphire; and (10) diamond.
Page 96 - It may also be defined as the sine of the angle of incidence divided by the sine of the angle of refraction, as light passes from air into the substance.
Page 35 - Avogadro's principle or hypothesis, which states that equal volumes of all gases under the same conditions of temperature and pressure contain the same number of molecules, was the extension of Dalton's Atomic Theory necessary to put the theoretical interpretation of chemistry on a solid foundation.
Page 29 - The specific gravity of a substance is its density compared with water, or the number of times heavier a given volume of the substance is than an equal volume of water. It is obtained by weighing a piece of the mineral or rock in air and then in water; the difference between the two is equal to the weight of an equal volume of water (the volume displaced), and we have...
Page 48 - The sine of the angle of incidence bears a constant ratio to the sine of the angle of refraction.
Page 91 - ... or where k = GM and v is the velocity at any point on the ellipse distant r from F. Energy Depends Only on the Major Axis. Thus the total energy of a mass (in reality of both masses) describing an ellipse is the same as that for the same bodies when a circle is being described if the major axis of the ellipse is equal to the diameter of the circle (Fig. 3-3). The minor axis does not count in the energy — it helps to fix the focus. The student probably knows that in our solar system the planets...
Page 1 - A mineral species is a natural inorganic substance which is either definite in chemical composition and physical characters or varies in these respects between definite natural limits
Page 12 - Consists of those crystals which have one axis at right angles to the other two, which are not at right angles to each other ; when transparent, they are optically biaxal ; as oxalic acid.
Page 123 - XXVI, 1908, p. 377. this combination is to produce zero rotation in each half wedge, where the plate and wedge have the same thickness.
Page 47 - The fundamental law of reflection is that the incident and reflected rays lie in the same plane with the normal to the reflecting surface at the point of incidence, and make equal angles with the normal on opposite sides.

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