Georges-Louis Le Sage

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Georges-Louis Le Sage

Georges-Louis Le Sage (born June 13, 1724 in Geneva ; † November 9, 1803 ibid) was a Geneva physicist and teacher of mathematics . He became famous for the Le Sage Gravitation , named after him , for his invention of one of the first electric telegraphs and his anticipation of the kinetic gas theory .

Life

Le Sage's father was Georges-Louis Le Sage from Couches in Burgundy , a descendant of Théodore Agrippa d'Aubigné and his mother was Anne Marie Camp. His father, the author of many scientific and philosophical works, occupied his son with various scientific topics from a very early age, for example the work of the Roman poet Lucretius at the age of 13. According to Le Sage's records, his parents' upbringing was very strict and the son responded by isolating himself and quietly beginning to meditate intensely on various subjects. In contrast to his father, who, at least according to the son, was primarily interested in simple facts and not in generalizations, the son was primarily interested in general and abstract principles. This was aided by his poor memory and habit of meditating.

Le Sage received his first regular training at the University of Geneva, where he was on friendly terms with Jean-André Deluc . He studied mathematics under Gabriel Cramer and physics under Calandrini. Later he reluctantly decided to study medicine in Basel and to give a few students private mathematics lessons. Here he also made the acquaintance of Daniel Bernoulli, whose reflections on kinetic gas theory influenced him very much. Le Sage left Basel to continue his medical studies in Paris, where he also devoted himself to his physical considerations.

When he finally returned to Geneva to practice as a doctor, he was refused permission because his father was not born in Geneva but in France. Against the wishes of his father, Le Sage therefore spent his life as a private teacher of mathematics and, above all, he was looking for a mechanical explanation of gravity . He also applied for a chair as professor of mathematics in Geneva, but failed. In Geneva, Le Sage finally made friends with Charles Bonnet .

Although Le Sage did not publish very much in his life, he was in lively correspondence with people such as Jean le Rond d'Alembert , Leonhard Euler , Paolo Frisi , Roger Joseph Boscovich , Johann Heinrich Lambert , Pierre Simon Laplace , Daniel Bernoulli , Firmin Abauzit , Lord Stanhope etc.

As a private tutor for mathematics, he had students such as La Rochefoucauld , Christoph Friedrich von Pfleiderer , the later famous mathematician Simon L'Huilier and Pierre Prévost , who were deeply impressed by his personality. He carried the title of "Correspondent of the Paris Academy of Sciences " and was since 1775 a member ( Fellow ) of the Royal Society . Le Sage died in Geneva after a brief, painful illness.

Personality and health

Le Sage described his way of thinking and working with the words:

“I have been born with four dispositions well adapted for making progress in science, but with two great defects in the faculties necessary for that purpose. 1. An ardent desire to know the truth; 2. Great activity of mind; 3. An uncommon (justesse) soundness of understanding; 4. A strong desire for precision and distinctness of ideas; 5. An excessive weakness of memory; 6. A great incapacity of continued attention. "

“I was born with 4 dispositions, which are well suited to making progress in science, but also with 2 defects in the areas that are necessary for this purpose. 1. An ardent need to know the truth. 2. Great activity of the mind. 3. An unusual skill of understanding. 4. A strong need for specificity and clarity of ideas. 5. An extraordinary weakness of memory. 6. A great incapacity for continued attention. "

- Playfair : 1807, p. 145

Le Sage also suffered from insomnia and this often resulted in total incapacity for work for days. In addition, he had an accident in 1762 that left him almost blind for the rest of his life. To compensate for the weakness of his memory, he wrote his thoughts on various cards or pieces of paper - over 35,000 of these pieces of paper are still in the University Library of Geneva.

As a consequence of his mental disposition, many of his works remained unfinished, for example his main work on gravitation; his treatise on ultimate causes; his biography of Nicolas Fatio de Duillier ; the history of gravitational theories. However, some of these works were published by Pierre Prévost after Le Sage's death .

telegraphy

In 1774 he developed the first form of electrical telegraphy , using 24 different wires - one for each letter of the alphabet . This telegraph connected two rooms.

Kinetic gas theory

Le Sage was aware of the analogy between his theory of gravity and the nature of gases, and so he tried to explain the latter phenomenon as well. This attempt was recognized by Rudolf Clausius and James Clerk Maxwell . In 1866 Maxwell wrote of Le Sage's theory of gases:

"His theory of impact is faulty, but his explanation of the expansive force of gases is essentially the same as in the dynamical theory, as it now stands."

"His collision theory is flawed, but his explanation of the expansive force of gases is basically the same as in the dynamic theory as it now exists."

- Maxwell : 1866

However, Le Sage made it clear that he was not the first to describe such a mechanism, but also cited Lucretius , Gassendi , Hermann and Daniel Bernoulli .

Gravity

Main article Le Sage Gravitation

In his early youth, Le Sage was heavily influenced by the writings of Lucretius and used some of this idea for his theory of gravity, which he worked on until the end of his life. Le Sage wrote on one of his cards that he had already developed the main features of the theory in 1743. On January 15, 1747, Le Sage wrote to his father:

“Eureka, Eureka. Never have I had so much satisfaction as at this moment, when I have just explained rigorously, by the simple law of rectilinear motion, those of universal gravitation, which decreases in the same proportion as the squares of the distance increase. "

“Eureka, Eureka. I have never had such satisfaction as at this moment in which I have just rigorously and based on the simple law of linear motion, reduced universal gravity, and which decreases in the same proportion as the square of the distance increases. "

- Evans : 2002, p. 18

The first elaboration of the theory - "Essai sur l'origine des forces mortes" - was sent by him to the Academy of Sciences in Paris in 1748, but rejected and never published. In 1756 Le Saga's thoughts were published for the first time in a journal and in 1758 he finally sent a more detailed version of his theory under the name "Essai de Chymie Méchanique" to a competition of the Academy of Sciences. In this work he tried to explain both the nature of gravity and that of chemical affinities. He won the award together with a competitor and therefore garnered the attention of prominent contemporaries like Euler . A few copies of this article - significantly expanded - were printed in 1761. The elaboration of the theory, however, which became accessible to a wider audience, was the "Lucrèce Newtonia" in which the connection with Lucretius' concept was fully developed. The most detailed compilation of the theory was published posthumously by Prévost in 1818 , but this version contains very little that was not published before.

Le Sage's predecessor

Le Sage wasn't the first to come up with such a theory. It was him doing Nicolas Fatio de Duillier , Gabriel Cramer and Franz Albert Redeker come before. The extent of the influence of these scholars on Le Sage is not clear.

Fatio

Fatio, a friend of Isaac Newton and Christiaan Huygens , proposed a theory in the 1690s that was practically identical to that of Le Sage. Fatio was a well-known Swiss personality and his mechanical explanation of gravity was his most important achievement along with the theory of zodiacal light .

Le Sage said he first heard of Fatio from his father when he heard the prophecies of the Camisards , because Fatio was a member of an extreme wing of this religious sect. Le Sage's father was well versed in the scientific fields in which Fatio worked, but Le Sage found that he had never told him anything about his theory of gravity. (To what extent Le Sage's pathologically poor memory played a role is unknown). In any case, Le Sage stated that Fatio's theory was only made known to him by his teacher Cramer in 1749, i.e. after his own first manuscript had been written.

A few years after Fatio's death (1753), Le Sage began to acquire Fatio's papers in order - according to his own statement - to save them from destruction and to write a history of the theories of gravity and a biography of Fatio. These Geneva manuscripts (in fragmentary form), including a Latin didactic poem in the Lucretian style , were brought to the Geneva University Library by Prevost after Le Sage's death and are still there.

Comparison of Fatio's writings Zehe (1980), pp. 285-309
The Bopp Edition is a complete reprint of the only completely remaining manuscript by Fatio from 1701, which was owned by Jakob Bernoulli and published by Karl Bopp in 1929. It contains all parts of the Geneva manuscripts or fragments and also contains problems 2, 3, 4, i.e. the most complex parts of his work.

The Gagnebin Edition is based on three of the six Geneva manuscripts owned by Le Sage and was published by Bernard Gagnebin in 1949. It contains changes up to 1743, i.e. 40 years after the Bopp manuscript was written, but only contains half of the text of the Bopp Edition. For example, problems 2, 3, 4 are completely absent because Gagnebin ignored manuscripts 4, 5, 6.

Geneva manuscript or fragments Corresponding sections of the Gagnebin Edition Date of transmission
to Le Sage
Corresponding pages of
the Bopp edition
GM1 34-52 March 29, 1766 by JP Mallet Pp. 38-45
GM2 1-24 October 17, 1770 by F. Jallabert Pp. 22-30
GM3 16-35 Unknown Pp. 27-38
GM4 Not included Unknown Pp. 50–56 (problem 4)
GM5 Not included, but the first part is similar to 27-34 (problem 1) Unknown Pp. 32–35 (problem 1), 47–50 (problem 2 & 3), 53–58 (problem 4)
GM6 Not included, but some parts are similar to 5, 7-10, 12-16, 19-23, 27-36 May 21, 1758 by Firmin Abauzit Partly pp. 22–39 and 47–49 (problem 2)

Le Sage wrote to Johann Heinrich Lambert in 1769: “ Nicolas Fatio de Duillier drafted a theory in 1689 which is so similar to mine that it only differs in the elasticity that he gives his violently moving matter. “So here he was showing the great similarity between the theories, even though he falsely claimed that Fatio was assuming fully elastic collisions, which they did not. Le Sage wrote a letter to Boscovich in which he announced the beginning of the Latin didactic poem by Fatio and announced that he would publish this work by Fatio. However, Boscovich advised against publication, as not many people would know what to do with it in the Latin form.

Le Sage was concerned that someone could accuse him of adopting his idea of ​​gravity from Fatio. So he had a "certificate" drawn up in which his two learned friends Christoph Friedrich von Pfleiderer and JP Mallet confirmed that, with the exception of the Abauzit manuscript, Le Sage saw no papers from Fatio before 1766, and there was nothing in these papers had not already been specified by Le Sage in more precise form.

In the “Physique Mecanique”, Fatio von Le Sage is mentioned in connection with the network structure of matter, but he claimed here that he had developed his idea in 1763, before he had come into possession of the relevant Fatio papers. However, an exact table of contents of the manuscript from 1758 shows that this work by Fatio already contains an exact representation of the network structure. Prevost and Le Sage also claimed in the same paper that Fatio assumed elastic collisions and thus did not explain gravity at all. Zehe tried to explain this misrepresentation by stating that Le Sage apparently did not study Fatio's papers very carefully.

In general, Le Sage and Prevost claimed that Le Sage's theory was superior to that of Fatio, but a close analysis of Zehe shows that Fatio's theory was further developed.

Cramer, Redeker

In his own words, Le Sage was informed of Cramer's theory by Abauzit in 1748, who Le Sage's teacher had been in Geneva. Le Sage later responded in two ways to allegations that his theory of gravity was based on a study of Cramer's writings.

  1. He argued that his first essay was written before studying Cramer's script.
  2. But even if he had known about it, it wouldn't matter, since Cramer's work was scientifically insignificant. Le Sage then repeated Fatio's accusation that he had stolen his (Fatio's) theory.

In 1751, Le Sage also became acquainted with Redeker's theory and he wanted to describe Redeker's theory (alongside that of Fatio) in his history of gravitational theories, but he did not complete his project.

Summary

Although Le Sage acknowledged that he was not the first to develop such a model, he claimed that he was the first to fully think it through. For example in “Lucrece Newtonia” he wrote that while it is quite possible that some - without naming their names - have anticipated him, but if so, they have presented the idea in a vague and misguided way. He also asked the rhetorical question why they did not draw the conclusions from their assumptions and did not share their research results. In response, he indicated that they just did not understand the principles of the theory, nor had enough love for the truth or the courage to convey their ideas clearly.

Prevost praised his friend Le Sage for mentioning his predecessors in all of his writings. However, this is not always the case, see above. Lord Kelvin and Samuel Aronson also later repeated Prevost's positive comments about Le Sage.

literature

  • P. Prévost (Ed.): Notice de la Vie et des Ecrits de George Louis Le Sage . JJ Paschoud, Geneva / Paris 1805 ( uni-goettingen.de ).
  • John Playfair : Notice de la Vie et des Ecrits de George Louis Le Sage . In: Edinburgh Review . 1807, p. 137–153 ( full text at Wikisource - English summary).
  • T. Thomson: Biographical account of M. Le Sage . In: Annals of Philosophy . 1818, p. 241-252 ( GoogleBooks ).
  • R. Wolf: George-Louis Le Sage . In: Biographies on the cultural history of Switzerland . tape 4 , 1862, p. 173-192 ( GoogleBooks ).
  • JC Evans: Gravity in the Century of Light: Sources, Construction and Reception of Le Sage's Theory of Gravitation . In: MR Edwards (Ed.): Pushing Gravity: New Perspectives on Le Sage's Theory of Gravitation . C. Roy Keys, Montreal 2002, p. 9-40 .
  • Jutta Berger †: On the history of the ether in the 18th century. George-Louis Lesage's system of corpuscules ultramondains. (PDF; 196 kB) In: Gesnerus , 62, 2005, pp. 186–217

Web links

Individual evidence

For complete references, see the biographies and the article Le Sage Gravitation .

  1. ^ Pierre Prévost: Notice de la Vie et des Ecrits de George Louis Le Sage . Geneva 1805, p. 141 ( archive.org ).
  2. ^ Entry on Sage, George Louis Le (1724-1803) in the archives of the Royal Society , London
  3. Louis Figuier-Furne, Télégraphie aérienne, électrique et sous-marine, cable transatlantique, galvanoplastie, dorure et argenture électro-chimiques, aérostats, éthérisation, Paris, Jouvet, coll. “Les Merveilles de la science ouions description populaire des inventions modern” , 1868 page 90
  4. Mercure de France, May 1756, 153-171
  5. Le Sage, 1761
  6. Le Sage, 1784
  7. Le Sage, 1818
  8. Chabot, 2004, p. 193