() ()R x

Assuming that FitzGerald was right in his contraction hypothesis, Trouton sought for more positive evidence of its truth. In 1908 with A.Rankine, Trouton made an attempt to measure the change of resistance of a wire when oriented from parallel to transverse to the ether drift. Four rectangular coils were wound, mounted on a common stand and connected in such a way that they formed a Wheatstone network, the wires forming opposite arms of the bridge being parallel. The bridge was balanced when the wire in two of the coils was at right angles to the ether drift and then the whole assembly was rotated through 90 degrees and the change of balance was tested. Every realizable precaution was taken only to lead to a negative result as recorded in Proc. Roy. Soc. 80A, 420-435, 1908. In the following we will give a detailed description of the experiment that meant the end of the “FitzGerald Contraction Hypothesis”