Appel à candidatures Prix Maurice Allais de Science Économique 2025

Call for submissions The 2025 Maurice Allais Prize in Economic Science

Maurice Allais’s experimental research in mechanics; his observations of anomalies in the movement of a pendulum

By Jean-Bernard DELOLY

These observations were conducted between 1954 and 1960: see the account of this research (cliquez ICI) and the table “Expérimentations conduites par Maurice Allais ou sous sa direction” [Experimentation conducted by Maurice Allais or under his direction] (cliquez ICI).

1 – His research into a link between electromagnetism and gravitation

It was while researching the possible influence of a powerful magnetic field on a non-magnetic pendulum that Maurice Allais discovered the existence of apparently inexplicable anomalies in the movement of a short pendulum and this is what gave rise to the exhaustive experimentation programme which he carried out between 1954 and 1960 using his “paraconic” pendulum, this time with the aim of seeking links between these anomalies and the evolution of the astronomical configuration.

His abandonment of his original objective was not due to failure. In fact, after attentive analysis of the results obtained, Allais considered that there probably was an action of magnetic fields on a non-magnetic pendulum and that the experiments ought to be rerun using more powerful magnetic fields.

An overview of this research was presented in an article in the review “Fusion” in 2001 (“Sur une liaison entre l’électronique et la gravitation. L’action d’un champ magnétique sur le mouvement du pendule » [On a link between electronics and gravity. The action of a magnetic field on the motion of a pendulum] – Fusion, n° 87, September-October 2001, pp. 47-53).

2 – His observations using a “paraconic” pendulum (1954-1960)

2-1 They are presented in a detailed way in its fundamental work “L’Anisotropie de l’Espace”  [The Anisotropy of Space, english translation by Thomas J. Goodey, René Verreault, Arjen Dijksman, 2019, L’Harmattan], which covers besides its whole experimental work and the theoretical reflections which result from it.

A presentation shortened, but which remains detailed, was done by Jean-Bernard Deloly: “Maurice Allais’s pendulum: discovered phenomena”.

Only “The Anisotropy of Space” (and thus, to a certain extent, the previous shortened presentation) covers actually all the observations. In particular no other publication describe the extremely interesting observations done with the “isotropic” pendulum, from 1958 till 1960. It’s the same as regards the long periodic components (monthly, half-yearly) discovered by Maurice Allais.

2-2 They were the subject of several short summaries by Maurice Allais himself:

– In the context of a paper recapitulating this research up to 1957 which was published in early 1958 in “Perspective X”, the review of the École Polytechnique, under the title “Doit-on reconsidérer les lois de la gravitation ?” [Should the laws of gravitation be reconsidered ?] (pp. 90-104). The text of this paper was reprised in an article in the review “Fusion” in 1998 (Fusion, November-December 1998, pp. 40-53).

An English translation of this paper was subsequently published as two successive articles in the American review “Aero-Space Engineering”, at the recommendation of NASA director Wernher von Braun, under the title “Should the laws of Gravitation be Reconsidered ?” (Aero/Space Engineering, September 1959, n° 9, pp. 46-52, October 1959, n° 10, pp. 51-55, November 1959, n° 11, p. 55). It was to play a decisive role in making known Maurice Allais’s research.

It should be remembered that between 1957 and 1960 numerous publications and in-depth debates addressed Maurice Allais’s research without enabling his results to be invalidated, notwithstanding the hostility they had aroused on the part of a considerable section of the scientific community.

See for instance the following extract from a letter from General Bergeron to Wernher von Braun in May 1959:

Before writing to you I thought it necessary to visit both of Professor Allais’s laboratories (one of which is located 60 m underground) in the company of eminent specialists – including two professors at the École Polytechnique. In the course of a discussion which lasted several hours, it was not possible to locate any significant source of error or any attempted explanation which resisted analysis.

 “I think I ought also to inform you that in the course of these last two years, more than ten members of the Académie des Sciences and more than thirty eminent personalities, gravitation specialists off various kinds, have come to visit either his Saint-Germain laboratory or his underground laboratory at Bougival.

Detailed discussion took place, not only on these occasions, but also several times in various scientific milieux, notably at the Académie des Sciences and the Centre National de la Recherche Scientifique. None of them enabled any explanation whatsoever to be brought forward in the context of currently recognized theories.”

– In the context of a paper written for the benefit of NASA which, on the occasion of the total eclipse of the sun of 11th August 1999 whose path crossed the northern hemisphere, had launched the initiative of incitating scientists to do a maximum number of observations on the path of the eclipse and of setting up coordination between them.

The coordination did not really amount to much and owing to the departure, meanwhile, of the NASA official involved, and no compendium, nor even a simple summary, of the results obtained ever appeared. Hence no conclusion was drawn from the initiative as such: each investigator, on his own behalf, published (or not) his own findings. Some were positive, and some negative.

But the episode made a major contribution, especially via the Internet, to making known the existence of an “eclipse effect” and the role of Maurice Allais and it was on this occasion that this effect came to be known as the “Allais Effect”:

Decrypting the Eclipse- A Solar Eclipse, Global Measurements and a Mystery” : Click HERE

French Nobel Laureate turns back clock” :  Click HERE

On a more general level, it also provided the opportunity to make Maurice Allais better known as a physicist: see Henry Aujard’s article in the engineering review for graduates of the prestigious École Centrale des Arts et Manufactures: “L’effet Allais est bien une réalité – Les apports de l’éclipse du 11 août 1999 dans le domaine de la gravitation, et quand la NASA rentre en scène pour promouvoir l’effet Allais” [The Allais Effect is indeed a reality – what has been learned about gravitation from the eclipse of 11th August 1999, and when NASA takes the floor to promote the Allais effect] (Revue des Centraliens, June 2000, pp. 32-35).

2-3 Maurice Allais’s experiments using the paraconic pendulum were also the subject of other detailed publications, notably in the Proceedings of the Académie des Sciences.

The experiments involved were intended both to increase knowledge of the pendulum’s functioning and to bring to light new phenomena. The magnitude measured was the azimuth of the plane of oscillation of a pendulum after 14 minutes, the pendulum being relaunched every 20 minutes.

A crucial feature of these experiments is that they were conducted continuously over a one-month period (the duration required to distinguish a lunar diurnal component in the harmonic analysis, of period 24 h 50 min, from the 24 h component). They are summarised in the table “Experiments carried out by Maurice Allais or under his direction” (Click HERE).

▪ Although it is no substitute for reading Allais’s major work on the subject “L’anisotropie de l’espace” [The anisotropy of space] (Editions Clément Juglar, 1997, 757 pp.), study of these documents will enable the reader to obtain already a very clear idea of the device used by Allais (a 1 m long pendulum suspended by a steel ball, which he called a “paraconic pendulum”), the procedure followed, a part of the results he obtained and of the solidity of his approach, which took great care:

  • to obtain statistical confirmation of the physical reality of the periodic components of about 24 h and 24 h 50 which had been detected (for this purpose Allais made use of a statistical significance test which he developed himself);
  • to ensure that no known phenomenon enabled the components to be explained, especially the lunar diurnal component of 24 h 50 min.

One of the accounts is specifically devoted to the eclipse of 30th June 1954.

Another treats specifically the July 1958 observations, conducted in tandem in the Saint-Germain laboratory and in a chalk quarry at Bougival, 6.5 km away (57 m vertically underground with 800 m horizontal distance to the free surface, which excludes any influence due to temperature variation). The 24 h 50 components were practically in phase. It is noteworthy that they were also in phase with the 24 h 50 component detected in the programme of observations of deviations of sightings on fixed sighting marks carried out over the same period (cf. “L’anisotropie de l’espace”, chap. 3).

Maurice Allais also studied very carefully the behaviour of the pendulum and in particular the influence of the anisotropy of its support: in particular he ensured that the two pendulums used in July 1958 had almost exactly the same characteristics.

▪ The documents concerned are the following:

“Observation des mouvements du pendule paraconique” [Observation of movements of the paraconic pendulum] (Proceedings of the Académie des Sciences, vol. 245, 13th November 1957, n° 20, pp. 1697-1700): Click HERE

The movements of a pendulum suspended from a steel ball display periodic components. The device used and the experimental procedure are described. The movements observed are due to a combination of four effects: the Foucault effect, a restoring force from the suspension, the random influence of the steel balls and finally a periodic influence.”

“Analyse harmonique des mouvements du pendule paraconique” [Harmonic analysis of the movements of the paraconic pendulum] Proceedings of the Académie des Sciences, vol. 245, 25th November 1957, n° 22, pp. 1875-1878: Click HERE

Harmonic analysis of the movements of the paraconic pendulum shows the existence of highly significant periodic components of the order of 24 h and 24 h 50 min. This periodic structure cannot be interpreted as due to perturbations of a random nature. Neither can it be interpreted as due to an indirect influence of temperature, pressure or magnetism.

“Mouvement du pendule paraconique et éclipse totale du soleil du 30 juin 1954” [Motion of the paraconic pendulum and total eclipse of the sun 30th June 1954] Proceedings of the Académie des Sciences, vol. 245, 4th December 1957, n° 23, pp. 2001-2003: Click HERE

The plane of oscillation moved about 15 grads [= 13.5°] at the moment of the total eclipse of the sun on 30th June 1954. The forces involved are of the same order of magnitude as those that correspond to the Foucault effect. It seems that the observed perturbation must be interpreted as due to the effect of the eclipse.”

“Théorie du pendule paraconique et influence lunisolaire” [The theory of the paraconic pendulum and lunisolar influence] (Proceedings of the Académie des Sciences, vol. 245, 16th December 1957, pp. 2170-2173): Click HERE

“It does not seem possible to explain the significant lunisolar components of the movement of the paraconic pendulum in terms of the current theory of gravitation, nor to attribute them to an indirect influence transmitted via the support or the atmosphere.

The observed effects therefore appear to be abnormal and in the present state of our information and of discussion of the issue, they would appear in all respects to be a new phenomenon.”

“Application du test de Schuster généralisé à l’analyse harmonique des azimuts du pendule paraconique” [Application of the generalized Schuster test to the harmonic analysis of the azimuths of the paraconical pendulum] (Proceedings of the Académie des Sciences], vol. 245, 23rd December 1957, n° 26, pp. 2467-2470):  Click HERE

The application of the generalisation of the Schuster test proposed in a preceding note to the results obtained by harmonic analysis of the azimuths of the paraconic pendulum shows that explanation in terms of purely fortuitous causes of the presence of a period close to 25 h and of amplitude equal to that detected is of very slight probability.

“Nouvelles expériences sur le pendule paraconique à support anisotrope” [New experiments on the paraconic pendulum with anisotropic support] (Proceedings of the Académie des Sciences, vol. 247, 3 November 1958, n° 18, pp. 1428-1431): Click HERE

The experiments on the paraconic pendulum with anisotropic support were resumed in July 1958 simultaneously at Saint-Germain and at Bougival, more than 50 m underground. These experiences revealed that the anomalies previously detected in the pendulum movement remained present.

“Détermination expérimentale de l’influence de l’inclinaison de la surface portante sur le mouvement du pendule paraconique à support anisotrope” [Experimental determination of the influence of the angle of inclination of the support surface on the movement of the paraconic pendulum with anisotropic support] (Proceedings of the Académie des Sciences, vol. 248, 19th January 1959, pp. 359-362): Click HERE

Comparison of the experimental results obtained by varying the angle of inclination of the surface supporting the steel ball of the paraconic pendulum, either in the course of releases in a given azimuth or during doubly enchained experiments, shows that the periodic variations of the azimuth over time cannot be interpreted as due to variations in the angle between the support and the vertical.

“Détermination expérimentale de l’influence de l’anisotropie du support sur le mouvement du pendule paraconique à support anisotrope” [Experimental determination of the influence of support anisotropy on the motion of the paraconic pendulum with anisotropic support] (Proceedings of the Académie des Sciences, vol. 248, 9 February 1959, pp. 764-769): Click HERE

The influence of the support on the movement of the paraconic pendulum may be obtained by study of the correlation between the characteristic elements of the movement and the starting azimuth.”

▪ Under the direction of Christian Marchal, in 1998, a team analysed the 7 monthly azimuth series obtained by Maurice Allais using the “anisotropic” paraconic pendulum. This analysis consisted chiefly in rerunning the harmonic analysis of each series.

The main findings were published in an article in “La Jaune et la Rouge”:

Essai d’analyse des expériences de Maurice Allais sur le pendule paraconique  [Attempted analysis of Maurice Allais’s experiments on the paraconic pendulum]” (September 1998): Click HERE

This article was itself the subject of remarks and commentaries by Maurice Allais, which appeared in a new article in “la Jaune et la Rouge” (January 1999, pp. 31-34): Click HERE

The results of the harmonic analyses carried out by Maurice Allais were strikingly confirmed.