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Rh [Note. These experiments were repeated during the early part of February, 1904, when the earth's orbital velocity conspires approximately with that of the solar system in space. The conditions for observation were quite as favourable as before; but no effect could be detected. With glass, the optical system was rotated through several quadrants consecutively so as to observe any possible trace of an effect. Observations were made at noon and at 6 P.M.

Hicks, in a more rigorous discussion than that of Lorentz, of the effect to be expected in the Michelson-Morley experiment, shows that instead of a contraction of $$\tfrac{v^{2}}{2V^{2}}$$ in the direction of drift, there should be an elongation of $$\tfrac{v^{2}}{2V^{2}}$$, to account for the negative results of the observations. The experiment itself should thus disprove the FitzGerald-Lorentz hypothesis. Either, on any of the suppositions possible from Lorentz's point of view, viz. contraction along the drift and zero change at right angles, no contraction but extension at right angles to the drift or elongation along and at right angles to the drift, such that the difference is $$-\tfrac{v^{2}}{2V^{2}}$$, or, on the conclusion of Hicks, the effect to be observed by means of double refraction in the preceding experiments would be the same.— D. B. B.]