No. Diameter in mm. Name. Magnification. Diameters. 1 1.0–0.5 coarse sand ×10 2 0.5–0.25 medium sand ×10 3 0.25–0.1 fine sand ×10 4 0.1–0.05 very fine sand ×30 5 0.05–0.01 silt ×30 6 0.01–0.005 fine silt ×150 7 0.005–0.0001 clay ×150 [Illustration: Figures 39–42, show examples of the various degrees of perfection and relative positions of cleavage lines. Figure 39, illustrates pinacoidal cleavage in mica from granite. Magnified thirty diameters. Figure 40. A cleavage of orthoclase from augite syenite magnified twenty-seven diameters. Figure 41. Cleavage of epidote magnified sixty diameters. Figure 42. Cleavage of titanite magnified seventy-five diameters. Figure 43. Sodium fluosilicate crystals magnified seventy-two diameters. Figure 44. The same with aluminum fluosilicate magnified twenty-seven diameters. Taken from Rosenbusch, Mikroskopische Physiographie. ] [Illustration: Figure 45. Sodium and aluminum silicofluorid crystals magnified 100, 140 and 160 diameters. Figure 46. Potassium silicofluorid crystals magnified 130 diameters. Figure 47. Another preparation of the same magnified 140 diameters. Figure 48. Lithium and aluminum silicofluorid crystals magnified 100 diameters. Figure 49. Calcium silicofluorid crystals magnified 45 diameters. Figure 50. Another preparation of the same magnified 42 diameters. ] [Illustration: Figure 51. Calcium sulfate crystals magnified twenty diameters. Figure 52. Magnesium silicofluorid crystals magnified thirty diameters. Figure 53. Cesium aluminum sulfate crystals magnified twenty diameters. Figure 54. Ammonium magnesium phosphate crystals magnified ten diameters. Figure 55. The same crystallized from dilute solution magnified thirty diameters. Figure 56. Ammonium phosphomolybdate crystals magnified 140 diameters. ]