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.
Roberto Martins Searching for the Ether DIO 17
Much later, Courvoisier presented another confirmation of this effect. He compared the catalogues of time correction of the observatories of Greenwich, Potsdam, Buenos Aires and Mount Stromslo for the period from 1948 to 19 54.28 There was a nice agreement between the theoretical predictions and the observed time differences, especially in the case of the years 1951-1954.
Local comparison between pendulum clock and chronometer Courvoisier supposed that the rate of pendulum clocks would vary because of the periodical gravity changes, but mechanical chronometers should not suffer similar changes. Therefore it should be possible to observe effects due to the absolute motion of the Earth comparing pendulum clocks to mechanical chronometers at a single place. Comparisons were made both at Babelsberg and at Potsdam (with the help of Wanach). In his analysis, Courvoisier assumed the value D = +40° and obtained^ = 104° ± 9° and v = 750 km/s.
If the Lorentz contraction of the Earth produces gravitational effects, then it should be possible to find its influence on the tides. Esclangon analyzed a set of 166,500 tide measurements, made at Pola, on the Adriatic sea, from 1898 to 1916. He obtained a term with the period of on sidereal day, that could not be associated with the Sun or the Moon, and ascribed it to a “dissymmetry of space”.29 This tidal effect could be described as:
48 mm.cos (t -146.1°) + 25 mm.cos (t - 244.6°) (16)
If the local gravity undergoes periodic changes, it should be possible to detect this effect with sensitive gravimeters. In 1927 Courvoisier (with the help of Sergei Gaposchkin) attempted for the first time to measure gravity variations using a very sensitive torsion gravimeter.30 The instrument could
detect a change Ag/g of 3xl0-^, corresponding to a displacement of 0.2 mm of the gravimeter pointer. From a series of measurements undertaken from 1927 to 1928 Courvoisier computed the following values:
A = 62° ± 5°; D = +32° ± 8°; v = 543 ± 55 km/s
28 Leopold Courvoisier, “Der Einfluss der ‘Lorentz-Kontraktion’ der Erde auf den Gang der Quarzuhren”, Experientia, ix (1953), 286-7; xiii (1957), 234-5.
29 Ernest Esclangon, “La dissymétrie de l'espace sidéral et le phénomène des marées”, Comptes rendus de l’académie des sciences de Paris, clxxxiii (1926), 116-18.
30 Leopold Courvoisier, “Über die Translationsbewegung der Erde im Lichtäther”,
Physikalische Zeitschrift, xxviii (1927), 674-80.