Contents. xiii 



Page 



Discovery of X-rays : hypotheses regarding them, . . 401 



Further researches of J. J. Thomson on cathode rays : the ratio m/e, 404 



Vitreous and resinous electricity, . . . 406 



Determination of the ionic charge by J. J. Thomson, . . 407 



Becquerel's radiation : discovery of radio-active substances, . 408 



CHAPTER XII. 



THE THEORY OF AETHER AND ELECTRONS IN THE CLOSING YEARS 

 OF THE NINETEENTH CENTURY. 



Stokes' theory of aethereal motion near moving bodies, . . 411 



Astronomical phenomena in which the velocity of light is involved, 413 



Crucial experiments relating to the optics of moving bodies, . 416 



Lorentz' theory of electrons, ...... 419 



The current of dielectric convection : Rontgen's experiment, . 426 



The electronic theory of dispersion, ..... 428 



Deduction of Fresnel's formula from the theory of electrons, . 430 



Experimental verification of Lorentz' hypothesis, . . . 431 



Fitz Gerald's explanation of Michelson's experiment, . . 432 

 Lorentz' treatise of 1895, . . . . . . . 433 



Expression of the potentials in terms of the electronic charges, . 436 



Further experiments on the relative motion of earth and aether, . 437 

 Extension of Lorentz' transformation : Larmor discovers its 



connexion with Fitz Gerald's hypothesis of contraction, . 440 

 Examination of the supposed primacy of the original variables : 



fixity relative to the aether : the principle of relativity, . 444 



The phenomenon of Zeeman, ..... 449 



Connexion of Zeeman's effect with the magnetic rotation of light, . 452 



The optical properties of metals, ..... 454 



The electronic theory of metals, ..... 456 



Thermionics, ........ 464 



INDEX, . 470 



