| Description | Three or four years ago Alexander had an idea for an experiment to determine whether the aether is at rest in the the neighbourhood of Earth. This would be by splitting a beam of light, following Michelson in repeating Fizeau's experiment, directing one beam through water and the other air, then reversing this by reflection. He discusses how this would show whether or not this would reveal an error in [Augustin-Jean] Fresnel's value. The experiment posed formidable difficulties and he gave up the idea. In 1906 he had his demonstrator try some preliminary experiments to see if their apparatus was good enough. His subsequent reading has led him to Wood's and Drude's 'Optics' and he discusses the implications of these. Wood mentions an experiment by Hoch in 1869. Hoch did not think of using the orbital velocity of the Earth, as Alexander is proposing, and unless he has made a blunder, his experiment would either refute the formula of Wood and Drude, or prove the relative velocities of the Earth and aether.
He encloses two sheets of further explanation: the first commences 'The expression given by Wood and Drude for the velocity of light...'; the second commences 'The find the retardation of a light wave passing through a tube of water placed parallel to the direction of the Earth's motion...' |