CHAPTER I.

INTRODUCTORY OPTICS FOR OPTICAL MINERALOGY. Ordinary Light.—Plane Polarized Light.—Effects Produced by Crystal Sections on Transmitted Light.—Amorphous Bodies.—Isotropic Crystals.—Anisotropic Crystals.—Double Refraction.—Uniaxial Crystals.—Biaxial Crystals.—Principal Vibration Directions.—Axial Angle.—Dispersion. 1