xiv CONTENTS 



CHAPTER XXIII 

 TERRESTRIAL MAGNETISM 



The direction of the earth's lines of force at a given place To find the declination 

 To find the dip or inclination The earth inductor The intensity of the 

 field To determine the horizontal intensity H The vibration experiment 

 The deflection experiment Recording instruments Results Sketch of 

 Gauss's theory of terrestrial magnetism Pp. 301-319 



CHAPTER XXIV 

 MAGNETISM AND LIGHT 



The Faraday rotation Faraday's successors Verdet's constant and its variation 

 with wave h ngth Effect of rise of temperatnre Absolute values of Verdet's 

 constant Rotation by gases Rotation by films of iron, nickel, and cobalt 

 Representation of the rotation by two equal circularly polarised ra\s with 

 opposite rotations travelling with different velocities An electron theory of 

 the rotation Confirmations of the theory Magnetic double refraction when 

 the light ray is perpendicular to the lines of force Voigt's theory Magnetic 

 double refraction in colloids Magnetic double refractiou in pure liquids 

 The Kerr magnetic effect The Zeeman effect Lorentz's theory Zeeman's 

 veiification Pp. 320-340 



INDEX Pp. 341-345 



