Page:A history of the theories of aether and electricity. Whittacker E.T. (1910).pdf/455

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Closing Years of the Nineteenth Century.
435

By direct transformation from the original to the new variables it is found that, when quantities of order w2/c2 and wv/c2 are neglected, these equations take the form

,

where div1 d1 stands for

.

Since these have the same form as the original equations, it follows that when terms depending on the square of the constant of aberration are neglected, all electrical phenomena may be expressed with reference to axes moving with the earth by the same equations as if the axes were at rest relative to the aether.

In the last chapter of the Versuch Lorentz discussed those experimental results which were as yet unexplained by the theory of the motionless aether. That the terrestrial motion exerts no influence on the rotation of the plane of polarization in quartz[1] might be explained by supposing that two independent effects, which are both due to the earth's motion, cancel each other; but Lorentz left the question undecided. Five years later Larmor[2] criticized this investigation, and arrived at the conclusion that there should be no first-order effect; but Lorentz[3] afterwards maintained his position against Larmor's criticism.

Although the physical conceptions of Lorentz had from the beginning included that of atomic electric charges, the analytical equations had hitherto involved ρ, the volume-density of electric charge; that is, they had been conformed to the hypothesis of a continuous distribution of electricity in space. It might hastily be supposed that in order to obtain an

  1. Cf. p. 416.
  2. Larmor, Aether and Matter, 1900.
  3. Proc. Amsterdam Acad. (English ed.), iv (1902), p. 669.

2 F 2