Calendar: 1868-1869 Page 286

286 EVENING CLASSES Emission of Light The Origin of Colour in Bodies Optical Instruments The Eye and Vision Irra- diation VI Transformations of Radiations Phosphorescence Change produced by Heat Fluorescence Chemi- cal Effects of Light Photography VII Interference of Light Colours of Thin Plates Newton's Rings Diffraction Coloured Fringes VIII Polarization of Light by Reflection by Refraction and by Passing through Crystals Norremburg's Apparatus IX Double Refraction by Iceland Spar and other Crystals Circular Polarization Fresnel's Rhomb Polarization by Liquids The Saccharimeter Effects of Heat Pressure and Magnetism in Changing the Plane of Polarization Interference of Polarized Light XI Production of Sound by the Vibrations of Bodies The Tuning-fork Theory of Vibrations Longi- tudinal and Transverse Vibrations Harmonicons XII Propagation of Sound by Waves of Air and other Elastic Media Vibrations in Tubes Velocity of Sound Reflection of Sound Transmission by Solids and Liquids Communication of Vibrations XIII Relation between the Rate of Vibration and the Pitch of Sound The Siren Vibrations of Strings Harmonic Division of Strings The Monochord Stringed Instruments XIV Vibrations of Rods Plates Membranes Relation of the Mode of Vibration to the Pitch of the Note Reed Instruments Musical Intervals Combinations of Sounds XV Intensity of Sound Resonance Organ Pipes Singing Flames Beats Interference of Sound Harmonics Optical Representation of Vibratory Motions