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 has become known for the eponymous Le Sage gravitation, for his invention of the first electric telegraph and his anticipation of the kinetic theory of gases.

Life and education

Le Sage's father was Georges- Louis Le Sage from Conques in Burgundy and his mother was Anne Marie Gamp, a descendant of Théodore Agrippa d' Aubigné. His father, the author of many scientific and philosophical works, employed his son very early with various scientific topics, for example, the work of the Roman poet Lucretius at the age of 13 years. According to Le Sage 's education records of his parents were very strict, and the son responded by he isolated himself and began to meditate in silence intensively on various topics. In contrast to his father, who was only interested in simple facts, but not on generalizations in the first place, at least as stated by the son, the son was interested in the first line of general and abstract principles. This was encouraged to meditate through his weak memory and his habit.

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

When he finally came back to Geneva to practice there as a doctor, he was the denied because his father was not born in Geneva but in France. Against the will 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 gravitation. He also competed for a chair as professor of mathematics at Geneva, but failed. In Geneva, Le Sage finally closed and friendship with Charles Bonnet.

Although Le Sage has not published much in his life, as he had been in a lively epistolary contact 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 teacher of mathematics he had students like La Rochefoucauld, Christoph Friedrich von Pfleiderer, the later famous mathematician Simon Lhuilier and Pierre Prévost, who were deeply impressed by his personality. He bore the title of " correspondent of the Paris Academy of Sciences " and was a foreign member of the Royal Society. Le Sage died after a short and painful illness in Geneva.

Personality and health

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

" I have been born with four dispositions well angepasst for making progress in science, but with two great defects in the faculties Necessary for purpose did. 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 to excessive weakness of memory; 6 A great incapacity of continued attention. "

"I was born with four dispositions, which are to make progress in science is good, but also with two defects in the fields, which are necessary for this purpose. 1 A burning desire to know the truth. 2 Great activity of the mind. 3 An unusual skill of understanding. 4 A strong desire for accuracy and clarity of ideas. 5 An extraordinary weakness of memory. 6 A large incapacity for continued attention. "

Le Sage also suffered from insomnia and it often resulted in a complete inability to work for days. In addition, he had a 1762 accident that nearly blinded him for the rest of his life. To compensate for the weakness of his memory, he wrote down his thoughts on various card or piece of paper - about 35,000 of this list are still in the University Library of Geneva.

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

Telegraphy

In 1774 he developed a first form of electric telegraphy, which he used 26 different wires - one for each letter of the alphabet. This Telegraph combined two rooms together.

Kinetic theory of gases

Le Sage was himself was aware of the analogy between his theory of gravity and the nature of the gases, and so he tried to explain the latter phenomenon. This experiment was appreciated by Rudolf Clausius and James Clerk Maxwell. 1866 Maxwell wrote about 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 impact theory is flawed, but his explanation of the expansive force of the gases is basically the same as in the dynamic theory, as it now exists. "

However, Le Sage pointed out clearly that he was not the first to describe such a mechanism, but also quoted Lucretius, Gassendi, Hermann and Daniel Bernoulli.

Gravity

Main article Le Sage gravitation

In his early youth, Le Sage was greatly influenced by the influence of the writings of Lucretius and used some of these ideas for his theory of gravity, at which he worked until his death. Le Sage wrote on one of his cards that he had already in 1743 developed the theory in its basic features. 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. Never have I had such satisfaction as in this moment I just rigorous and based on the simple law of rectilinear motion, attributed the universal gravitation, and which at the same rate decreases as the square of the distance increases. "

The first elaboration of the theory - " Essai sur l' origine des forces mortes " - 1748 sent by him to the Academy of Sciences in Paris, rejected and never published. 1756 Le Sage's thoughts were first published in a magazine and in 1758 he finally sends a more detailed version of his theory under the name of " Essai de Chemistry more Méchanique " to a contest of the Academy of Sciences. In this work he tried to explain both the nature of gravitation as well as the chemical affinities. He won the award together with a competitor and therefore secured the attention of prominent contemporaries such as Euler. This paper was - significantly expanded - printed a few copies in 1761. However, the elaboration of the theory, which has a wider audience, was the " Lucrèce newtonien " in which it was the connection with Lucretius ' concept fully developed. The most extensive compilation of the theory was published posthumously in 1818 by Prévost, but this version contains very little that has not been published before.

Le Sage's predecessor

Le Sage was not the first who designed such a theory. There were present Nicolas Fatio de Duillier, Gabriel Cramer and Franz Albert Redeker occurred to him before. The extent of the influence of these scholars on Le Sage is not released.

Fatio

Fatio, a friend of Isaac Newton and Christiaan Huygens, designed in the 1690s, a theory which was practical identical to that of Le Sage. Fatio was a well-known Swiss and his mechanical explanation of gravity was in addition to the theory of the zodiacal light his most significant achievement.

Le Sage said he had by his father first heard of Fatio, as he heard the prophecies of the camisards because Fatio was a member of an extreme wing this religious sect. Le Sage's father was well versed in the scientific areas where Fatio worked, but Le Sage stated that he had never told him anything about his theory of gravitation. ( The extent to Le Sage pathologically bad memory played a role, is unknown). Anyway Le Sage stated that Fatios theory only in 1749 that he had been so familiar after writing his own first manuscript, by his teacher Cramer.

A few years after Fatios Death ( 1753) Le Sage began to acquire the papers Fatios to them - to preserve from destruction and to write a history of theories of gravity or a biography Fatios - according to his own testimony. This Geneva manuscripts ( in fragmentary form), which also include a Latin didactic poem in the style of Lucretius, were taken to the University Library of Geneva to Le Sage's death by Prevost and are still there.

The Bopp Edition is a complete reprint of the only remaining completely Fatios manuscript from 1701, which was owned by Jacob Bernoulli and published by Karl Bopp in 1929. It contains all the parts of the Geneva manuscripts or fragments and also includes the problems 2, 3, 4, so the most complex parts of his work.

The Gagnebin Edition is based on three of the six Geneva manuscripts, which were owned by Le Sage, and was published by Bernard Gagnebin 1949. It contains changes to 1743, ie 40 years after the Constitution of Bopp manuscript, but it contains only half the text of Bopp Edition. For example, missing issues 2, 3, 4 entirely because Gagnebin the manuscripts ignored 4,5,6.

Le Sage wrote to Johann Heinrich Lambert in 1769: " Nicolas Fatio de Duillier 1689 has a theory designed, which is so similar to mine that they are only in the elasticity which he gives his violently moving matter is different. " Here he laid so the great similarity between the theories is, although he falsely claimed that Fatio of completely elastic collisions went out, which was not the case. Le Sage wrote a letter to Boscovich, in which he announced the beginning of the Latin didactic poem of Fatio and announced to publish this work Fatios. Boscovich advised but from a publication, since not many could do something with it in its Latin form.

Le Sage was concerned that someone might accuse him that he had taken his idea to gravity of Fatio. So he had to create a " certificate " in which both his learned friends Christoph Friedrich von Pfleiderer and J. P. Mallet confirmed that has seen except the Abauzit manuscript Le Sage no papers of Fatio before 1766, and was in these papers nothing that has not already been stated by Le Sage in a more accurate form.

In the " Physique Mecanique " Fatio is mentioned by Le Sage in connection with the network structure of matter, but he claimed here that he developed his idea in 1763, ie, before he had come into possession of the papers correspond Fatios. However, an accurate synopsis of the manuscript of 1758 shows that already contains this work deals with Fatio an accurate representation of the network structure. Also Prevost and Le Sage argued in the same paper continues that Fatio assumed elastic collisions and thus have not explained gravity. Toe tried to explain this misrepresentation to the fact that Le Sage had apparently not been studied very closely Fatios papers.

Generally alleged Le Sage and Prevost that Le Sage's theory is superior to that of Fatio, but a detailed analysis of toe shows that Fatios theory was further developed.

Cramer, Redeker

Le Sage was informed by his own words of Abauzit 1748 Cramer's theory, which Le Sage's teacher in Geneva had been. Le Sage replied later in two ways to allegations that his theory of gravitation based on the study of Cramer's writings.

1751 Le Sage was also with the theory of Redeker known and he wanted Redeker theory describe (besides 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 have developed such a model, but he claimed for himself that he was the first who had fully thought through. For example, in " Lucrece newtonien " he wrote, that it was quite possible indeed that some - without mentioning their names - are beaten him to it, but if it is so, they have presented the idea in a vague and misguided way. He also provided the rhetorical question of why they have not taken the consequences of their assumptions and have not communicated their research results. In response, he indicated that they had just not quite understand the principles of the theory and not enough love for the truth or do not have enough courage possessed, clearly communicate their ideas.

Prevost praised his friend Le Sage for its mention of his predecessor in all his writings. This thing, however, not always the case, see above. Even Lord Kelvin and Samuel Aronson repeated later Prevost positive comment about Le Sage.