Chapter titles are ...(1) Introductory ...(2) The Early Experimenters ...(3) Emission of Negative Electrons in a Vacuum ...(4) The Velocity of the Electrons ...(5) The Photoelectric Current in Gases at Various Pressures ...(6) Photoelectric Substances: Solids and Liquids ...(7) Photoelectric Substances: Gases and Vapors ...(8) The Influence of Temperature on the Photoelectric Discharge ...(9) The Influence of the Character of the Light on the Photoelectric Discharge: Sources of Light, Influence of the Intensity of Light ...(10) The Influence of the Plane of Polarization and of the Wavelength of the Light ...(11) Photoelectric Fatigue ...(12) Fluorescence and Phosphorescence ...(13) Photochemical Actions and Photography.