Six Lectures on Light

Six Lectures on Light

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Title: Six Lectures on Light Delivered In The United States In 1872-1873
Author: John Tyndall
Release Date: November 10, 2004 [EBook #14000]
Language: English
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SIX LECTURES ON LIGHT
DELIVERED IN THE UNITED STATES IN 1872-1873
BY
JOHN TYNDALL, D.C.L., LL,D., F.R.S.
LATE PROFESSOR OF NATURAL PHILOSOPHY IN THE ROYAL INSTITUTION OF GREAT BRITAIN

[Illustration: Sir Thomas Laurence PRA Pinx
Henry Adlarc. Sc.
Signature: Thomas Young]
London: Longmans & Co.
SIXTH IMPRESSION LONGMANS, GREEN, AND CO.
39 PATERNOSTER ROW, LONDON
NEW YORK AND BOMBAY
1906

PREFACE TO THE FOURTH EDITION.
In these Lectures I have sought to render clear a difficult but profoundly interesting subject. My aim has been not only to describe and illustrate in a familiar manner the principal laws and phenomena of light, but to point out the origin, and show the application, of the theoretic conceptions which underlie and unite the whole, and without which no real interpretation is possible.
The Lectures, as stated on the title-page, were delivered in the United States in 1872-3. I still retain a vivid and grateful remembrance of the cordiality with which they were received.
My scope and object are briefly indicated in the 'Summary and Conclusion,' which, as recommended in a former edition, might be, not unfitly, read as an introduction to the volume.
J.T.
ALP LUSGEN: October 1885.

CONTENTS.
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.
Chromatic Phenomena produced by Crystals in Polarized Light The Nicol Prism Polarizer and Analyzer Action of Thick and Thin Plates of Selenite Colours dependent on Thickness Resolution of Polarized Beam into two others by the Selenite One of them more retarded than the other Recompounding of the two Systems of Waves by the Analyzer Interference thus rendered possible Consequent Production of Colours Action of Bodies mechanically strained or pressed Action of Sonorous Vibrations Action of Glass strained or pressed by Heat Circular Polarization Chromatic Phenomena produced by Quartz The Magnetization of Light Rings surrounding the Axes of Crystals Biaxal and Uniaxal Crystals Grasp of the Undulatory Theory The Colour and Polarization of Sky-light Generation of Artificial Skies.
LECTURE V.
Range of Vision not commensurate with Range of Radiation The Ultra-violet Rays Fluorescence The rendering of invisible Rays visible Vision not the only Sense appealed to by the Solar and Electric Beam Heat of Beam Combustion by Total Beam at the Foci of Mirrors and Lenses Combustion through Ice-lens Ignition of Diamond Search for the Rays here effective Sir William Herschel's Discovery of dark Solar Rays Invisible Rays the Basis of the Visible Detachment by a Ray-filter of the Invisible Rays from the Visible Combustion at Dark Foci Conversion of Heat-rays into Light-rays Calorescence Part played in Nature by Dark Rays Identity