CONTENTS. 



Page. 



rent bodies on light; M. Jamin's results. (204) Difference of phase 

 of the two components in light reflected from transparent bodies; 

 angle of maximum polarization. (205) Substances of positive and 

 negative reflexion. (206) Elliptic vibration of reflected light de- 

 termined experimentally. (207) Professor Haughton's researches ; cir- 

 cular polarization of reflected light, 181 



CHAPTER XII. 



FRESNEL'S THEORY OF DOUBLE REFRACTION. 



(208, 209) Form of the wave-surface in uniaxal crystals not general. 

 (210-212) Fresnel's theory of double refraction; surface of elasticity. 

 (213) Planes of polarization of two rays; law of Malus. (214) Fres- 

 nel's construction for the wave-surface ; its equation. (215) Direc- 

 tions, and planes of polarization, of the two rays determined. 

 (216) Optic axes ; velocities of the two rays. Normal velocities of the 

 waves; law of Biot. (217) Case of uniaxal crystals, and of single- 

 refracting substances. (218) Velocity of both rays in biaxal crystals 

 variable ; Fresnel's experiments. (.219) Sir "William Hamilton's dis- 

 covery of Conical refraction. (220-222) External conical refraction 

 established experimentally ; law connecting the planes of polarization ; 

 effect of linear aperture. (223) Internal conical refraetion, .... 197 



CHAPTER XIII. 



INTERFERENCE OF POLARIZED LIGHT. 



(224-226) Depolarization and colour produced by crystalline plates. 

 (227) Laws of the tints discovered by M. Biot. (228) The phenomena 

 reduced to principle of interference difficulty. (229) Laws of inter- 

 ference of polarized light ; explanation of colours of crystalline plates. 

 (230) Emergent light in general elliptically-polarized. (231-233) Cal- 

 culation of intensities and tints of the emergent pencils. Laws of the 

 colours deduced. (234) Colours produced by thick plates. (235) Rings 

 surrounding the optic axis in uniaxal crystals. (236) Rings in biaxal 

 crystals lemniscates ; dark brushes. (237-238) Double-refracting 

 structure developed by compression or dilatation ; Fresnel's explana- 

 tion. (239) Double-refracting structure produced by heat. (240) Effects 

 of pressure and heat on double-refracting crystals, 



