Roberto Martins Searching for the Ether DIO 17
Fig. 10. Courvoisier’s plumb line apparatus for measuring oscillations of the local gravitational vertical due to Lorentz contraction.
Similar observations were made by Esclangon, with the help of Andre-Louis Danjon, using two horizontal pendulums with perpendicular motions.25 One of the pendulums lead to .4=69°; for the second pendulum, .4=52°. Esclangon did not provide other information and did not attempt to compute the speed of the Earth.
25 Ernest Esclangon, “Sur la dyssimétrie mécanique et optique de l'espace en rapport avec le mouvement absolu de la Terre", Comptes rendus de Vacadémie des sciences de Paris, clxxxii (1926), 921-3.
Searching for the Ether
Another way of observing the variation of the local vertical direction, according to Courvoisier, was with the aid of bubble levels.26 He used two very sensitive level meters. One of them was attached to the floor of the Babelsberg underground clock room, and the other one was attached in a horizontal position to one of the columns of the same room. Courvoisier measured the difference between the marks of the two level meters. The maximum predicted effect was about 0.30", and with the delicate instruments used by Courvoisier it was possible to measure angular changes as small as 0,03". In the first series of measurements between 15 and 26 June 1929, Courvoisier obtained the following results:
A = 59° ± 6°; D = +51° ± 9°; v = 446 ± 34 km/s
Comparison between pendulum clocks at different places According to Courvoisier's hypothesis, the Earth undergoes a real contraction in the direction of its motion through the ether, and this contraction would produce observable periodical changes of the local value of gravity as a function of sidereal time. Pendulum clocks at different places of the Earth should show slightly different readings, and their phases should exhibit a periodical relative fluctuation. Courvoisier analyzed data on pendulum clocks of different astronomical observatories, in an attempt to detect this effect.
Using radio signals it was possible to compare the rates of clocks at very distant observatories. The Annapolis Observatory emitted regular time signals from its pendulum clocks. It was possible to compare the rate of those pendulums to those at another place. Courvoisier asked the help of Bernhard Wanach, from Potsdam, who compared the rate of the pendulum clocks of that observatory to the signals received from Annapolis, from September 1921 to November 1922.27 Courvoisier’s analysis of Wanach’s data led to the following results:
A = 56° ± 12°; D = +40° (estimated); v = 873 ± 228 km/s
Afterwards, a comparison was made using a comparison between the clocks of Annapolis, Potsdam, Ottawa, and Bordeaux. The mean result obtained by Courvoisier was:
A = 81° ± 5°; D = +34° ± 5°; v = 650 ± 50 km/s
26 Leopold Courvoisier, “Bestimmungsversuche der Erdbewegung relativ zum Lichtäther IV”, Astronomische Nachrichten, ccxxxvii (1930), 337-52; idem, “Ist die Lorentz-Kontraktion von Brehungsindex abhängig?”, Zeitschrift für Physik, xc (1934), 48-62.
27 Leopold Courvoisier, “Bestimmungsversuche der Erdbewegung relativ zum Lichtäther II”, Astronomische Nachrichten, ccxxx (1927), 425-32.