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 Eichenwald (Annalen der Physik 1903, 1904) rotated together both condenser and dielectric and found that the magnetic effect was proportional to the potential difference and to the angular velocity, but was completely independent of K. This is of course quite consistent with Rowland and Röntgen. Blondlot (Comptes Rendus, 1901) passed a current of air in a steady magnetic field H_{y}, (H = H_{z} = 0). If this current of air moves with velocity u_{x} along the x-axis, an electromotive force would be set up along the z-axis, due to the relative motion of matter and magnetic tubes of induction. A pair of plates at z = ±a, will be charged up with density ρ = D_{z} = KE = K. u_{s} H_{y}/c. But Blondlot failed to detect any such effect. H. A. Wilson (Phil. Trans. Royal Soc. 1904) repeated the experiment with a cylindrical condenser made of ebony, rotating in a magnetic field parallel to its own axis. He observed a change proportional to K — 1 and not to K. Thus the above set of electro-magnetic experiments contradict the Hertz-Heaviside equations, and these must be abandoned. [P. C. M.]  Note 2. Lorentz Transformation.

Lorentz. Versuch einer theorie der elektrischen und optischen Erscheinungen im bewegten Körpern.

(Leiden—1895).

Lorentz. Theory of Electrons (English edition), pages 197-200, 230, also notes 73, 86, pages 318, 328.

Lorentz wanted to explain the Michelson-Morley null-effect. In order to do so, it was obviously necessary to explain the Fitzgerald contraction. Lorentz worked on the hypothesis that an electron itself undergoes