VI11 CONTENTS. 



SECTION XVIII. 



Refraction Astronomical Refraction and its Laws Formation of Tables of 

 Refraction Terrestrial Refraction Its Quantity Instances of Extraor- 

 dinary Refraction Reflection Instances of Extraordinary Reflection 

 Loss of Light by the Absorbing" Power of the Atmosphere Apparent 

 Magnitude of Sun and Moon in the Horizon . . . Page 147 



SECTION XIX. 



Constitution of Light according to Sir Isaac Newton Absorption of Light 

 Colors of Bodies Constitution of Light according to Sir David Brew- 

 ster New Colors in the Solar Spectrum Fraunhofer's Dark Lines 

 Dispersion of Light The Achromatic Telescope Homogeneous Light 

 Accidental and Complementary Colors M. Plateau's Experiments and 

 Theory of Accidental Colors 153 



SECTION XX. 



Interference of Light Undulatory Theory of Light Propagation of Light 

 Newton's Rings Measurement of the Length of the Waves of Light, 

 and of the Frequency of the Vibrations of Ether for each Color New- 

 ton's Scale of Colors Diffraction of Light Sir John HerschePs Theory 

 of the Absorption of Light Refraction and Reflection of Light 161 



SECTION XXI. 



Polarization of Light Denned Polarization by Refraction Properties of 

 the Tourmaline Double Refraction All doubly Refracted Light is 

 Polarized Properties of Iceland Spar Tourmaline absorbs one of the 

 two Refracted Rays Undulations of Natural Light Undulations ot 

 Polarized Light The Optic Axes of Crystals M. Fresnel's Discoveries 

 on the Rays passing along the Optic Axis Polarization by Reflection 172 



SECTION XXII. 



Phenomena exhibited by the passage of Polarized Light through Mica and 

 Sulphate of Lime The Colored Images produced by Polarized Light 

 passing through Crystals having one and two Optic Axes Circular 

 Polarization Elliptical Polarization Discoveries of MM. Biot, Fresnel, 

 and Professor Airy Colored Images produced by the Interference of 

 Polarized Rays 180 



SECTION XXIII. 



Objections to the Undulatory Theory, from a Difference in the Action of 

 Sound and Light under the same circumstances, removed The Disper- 

 sion of Light according to the Undulatory Theory . . . 190 



SECTION XXIV. 



Chemical or Photographic Rays of the Solar Spectrum Messrs. Scheele, 

 Ritter, a-nd Wollaston's Discoveries Mr. Wedgewood and Sir Humphry 

 Davy's Photographic Pictures The Calotype The Daguerreotype 

 The Chromatype The Cyanotype Sir John Herschel's Discoveries in 

 the Photographic or Chemical Spectrum Mons. E. Becquerel's Discovery 

 of Inactive Lines in the Chemical Spectrum . . . 193 



