Allais and Esclangon light deviations

by Vincent MORIN


Maurice Allais is mainly known after his pendulum experiments, but he also experimented with optical sightings, and a small part of his 1997 book (l'anisotropie de l'espace Ed Clément Juglar Paris 1997) is devoted to those experiments.

In fact, in 1927, the french astronomer Ernest Esclangon already experimented in a similar direction, measuring vertical differences in north-east and north-west optical sightings.

In both cases, Esclangon and Allais said there was some deviations periodic in time. Esclangon said there was a sidereal periodicity in his vertical differences, Allais said his horizontal north to south and south to north sightings had 24h and nearly 25h periods.

At the time they were made, those measurements were very tedious (Allais experiments required measuring every 20 minutes 24h a day during one month). Today, with some adequate tecnical skills and affordable hardware, it is easy to set up a fully automated experiment where the deviations of a light beam are recorded continuously for months.

Two experiments have been conducted until now. The first one was a first low cost trial to see if something interesting happened. The second experiment is a more refined version of the first experiment. In both cases, the light beam undoubtedly undergoes periodic deviations, which is not a surprise as we expect at least the diurnal temperature effect. But it seems that the behaviour is much stranger than the temperature effect would normally appear, and it seems equally probable that some non thermal process operates.


Documents in pdf format describe the first and second experiments. The first document presents both the setup and three monthly series.

The second document is a technical description of the most recent setup built with Mr. Thomas Goodey support.

The third document is the preliminary report on more than 5 months data acquisition. It is the longest series collected to date (to my knowledge). The document contains many detailed graphs. Though prudence is in order in those matters, this new data goes in the direction of a confirmation of the first experiment. It seems fair to recognize the cause of those deviations is unclear, and multidirectional data appears more complicated than it could be anticipated. Writing of an analysis is underway and will complete the preliminary report made available below.

The 4th document is an article submitted to Physica Scripta without answer. It is especially cautious and put there otherwise discussion will occur years later.

The 5th document is the raw data collected with the second setup (glass tubes) from June 2004 to March 2005.


Click here to download the memoir on first experiments (3 Mb, pdf, in french).

Click here to download the second setup technical description(2 Mb, pdf, in english).

Click here to download the preliminary 2005 report on second setup data (4 Mb, pdf, in english).

Click here to download the January 2004 article report on December 26th 2004 observation (290 Kb, pdf, in english).

Click here to download the June 2004 to March 2005 raw data (890 Kb, zip file).

Click here to download the June 2004 to June 2006 experimental report (19.5 Mb, pdf file).

Vincent Morin (