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Published online by Cambridge University Press: 14 March 2018
Of the various methods employed or suggested for the graphical representation on a plane of points on the surface of a sphere, the most important to the crystallographer are the stereographic and the gnomonic projections. Both are in common use, and both have their particular advantages. Professor Penfield has recently published a series of papers in which he points cut the advantages that accrue from the employment of the stereographic projection both in crystallography and cartography. He has devised protractors and scales, which facilitate the construction of the projection of the poles of the faces bounding a crystal or of portions of the earth's surface, and enable the angles between points or contained by zones, i.e. great circles, to be readily determined from measurements on the plane diagram.
Page 309 note 1 ‘The stereographic projection and its possibilities from a graphical standpoint.’ Amer. Journ. Sci., 1901, ser. 4, vol. xi, pp. 1-24, 115-144 ; abstract, this vol., p. 203. ‘On the use of the stereographic projection for geographical maps and sailing charts.’ Amer. Journ. Sci., 1902, ser. 4, vol. xiii, pp. 245-275, 347-376; abstract, this vol., p. 806. ‘On the solution of problems in crystallography by means of graphical methods, based upon spherical and plane trigonometry.’ Amer. Journ. Sci., 1902, set. 4, vol. xiv, pp. 249-284 ; abstract, this vol., p. 306.
Page 310 note 1 This vol., pp. 122-150. A translation appealed in Zeits. Kryst. Min., 1903, vol. xxxvii, pp. 209-234.
Page 310 note 2 For other discussions of this projection see:–‘Crystallography ; a Treatise on the Morphology of Crystals,’ by N. Story-Maskelyne, Oxford, 1895, pp. 492—499. Miers, H. A., ‘The galomonic projection,’ Min. Mag., 1887, vol. vii, pp. 145–149 CrossRefGoogle Scholar. ‘Traité de Cristallographie,’ by E. Mallard, Paris, 1879, vol. i, pp. 63-66. ‘Projection und graphische Krystallberechnung,’ by V. Goldschmidt, Berlin, 1887.
Page 312 note 1 Cf. Story-Maskelyne and Miers, loc. cit.
Page 315 note 1 It may be noted that in the triclinic system P will not be a node of the network.
Page 319 note 1 Haidinger, ‘Account of the method of drawing crystals in true perspective, followed in the Treatise on Mineralogy of Professor Mohs.’ Mem. Weruerian Soc. Edinburgh, 1824-5, vol. v, pp. 485-508.
Page 320 note 1 ‘Lehrbuch der reinen und angewandten Krystallographie,’ Leipzig, 1880, vol. ii, pp. 400-483.
Page 320 note 2 Loc. cit., p. 401.
Page 320 note 3 Loc. cit., p. 403.
