Now, as we have mentioned, if in our frame of reference, on the earth’s surface, for instance, all things, including our measuring rods and our own bodies, contracted in exactly the same way owing to the motion of our planet through the ether, it would, of course, be idle for us to expect this contraction to be observable by direct measurement. But although not observable in a direct way, it was argued that this contraction of a body should modify its optical and electrical properties so that a study of the variations in these properties when the body was placed successively in different directions should yield us the earth’s motion through the ether. In particular the contraction of a solid transparent body, owing to its motion through the ether, should give rise to a phenomenon of double refraction, much as would follow from an ordinary physical compression of the body. The experiment of Rayleigh and of Brace was based on this idea, but the result was a complete disappointment. The FitzGerald contraction gave rise to no such effect, and a negative result was registered. The experiment of Trouton and Rankine aimed to detect a variation in the electrical conductivity of a strip of metal as a result of the FitzGerald contraction. Once more a negative result was the outcome. These experiments having failed, still another was suggested and carried out by Trouton and Noble. The essence of this experiment was based on the well-known phenomenon verified by Rowland, that an electrified body in motion produces all the effects of an electric current. If, therefore, two electrified bodies were placed side by side, the motion of the earth through the ether should produce two parallel electric currents; and since parallel electric currents attract one another, a very sensitive torsion balance should be able to detect this attraction. Again, the result of this experiment [Pg 134] was negative; the velocity of the earth through the ether evaded us completely. Now, it should be noticed that the last two experiments pertain purely to electricity and electrodynamics; there is nothing of an optical nature about them. Hence, it would appear that all electromagnetic phenomena behave in exactly the same way, regardless of the velocity of the ether hurricane. In other words, they, too, yield negative results. But there is yet another aspect to these experiments.