LECTURE I.

  Introductory
  Uses of Experiment
  Early Scientific Notions
  Sciences of Observation
  Knowledge of the Ancients regarding Light
  Defects of the Eye
  Our Instruments
  Rectilineal Propagation of Light
  Law of Incidence and Reflection
  Sterility of the Middle Ages
  Refraction
  Discovery of Snell
  Partial and Total Reflection
  Velocity of Light
  Roemer, Bradley, Foucault, and Fizeau
  Principle of Least Action
  Descartes and the Rainbow
  Newton’s Experiments on the Composition of Solar Light
  His Mistake regarding Achromatism
  Synthesis of White Light
  Yellow and Blue Lights produce White by their Mixture
  Colours of Natural Bodies
  Absorption
  Mixture of Pigments contrasted with Mixture of Lights

LECTURE II.

  Origin of Physical Theories
  Scope of the Imagination
  Newton and the Emission Theory
  Verification of Physical Theories
  The Luminiferous Ether
  Wave-theory of Light
  Thomas Young
  Fresnel and Arago
  Conception of Wave-motion
  Interference of Waves
  Constitution of Sound-waves
  Analogies of Sound and Light
  Illustrations of Wave-motion
  Interference of Sound Waves
  Optical Illustrations
  Pitch and Colour
  Lengths of the Waves of Light and Rates of Vibration of the
    Ether-particles
  Interference of Light
  Phenomena which first suggested the Undulatory Theory
  Boyle and Hooke
  The Colours of thin Plates
  The Soap-bubble
  Newton’s Rings
  Theory of ‘Fits’
  Its Explanation of the Rings
  Overthrow of the Theory
  Diffraction of Light
  Colours produced by Diffraction
  Colours of Mother-of-Pearl.

LECTURE III.

  Relation of Theories to Experience
  Origin of the Notion of the Attraction of Gravitation
  Notion of Polarity, how generated
  Atomic Polarity
  Structural Arrangements due to Polarity
  Architecture of Crystals considered as an Introduction to their
    Action upon Light
  Notion of Atomic Polarity applied to Crystalline Structure
  Experimental Illustrations
  Crystallization of Water
  Expansion by Heat and by Cold
  Deportment of Water considered and explained
  Bearings of Crystallization on Optical Phenomena
  Refraction
  Double Refraction
  Polarization
  Action of Tourmaline
  Character of the Beams emergent from Iceland Spar
  Polarization by ordinary Refraction and Reflection
  Depolarization.

LECTURE IV.