Jean-Baptiste Le Roy

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First page of the article “Coup foudroyant” written by Le Roy in the fourth volume of the Encyclopédie (1754).

Jean-Baptiste Le Roy (born August 15, 1720 in Paris , † January 21, 1800 in Paris) was a French scientist and one of the main contributors to the Encyclopédie for the field of technology .

In the scientific field, Le Roy dealt with a variety of topics; His research on electricity is of particular importance. Together with Patrick d'Arcy , he designed the first electrometer in 1749 , a device for detecting electrical charges and voltages. He also experimented with lightning rods and the use of electricity in the treatment of diseases.

As a contributor to the Encyclopédie , he wrote more than 130 articles under the author's abbreviation “T”, including on watchmaking , metalworking and mathematical instruments .

From 1772 to 1777 Le Roy was deputy director and from 1773 to 1778 director of the Académie royale des sciences .

life and work

Jean-Baptiste Le Roy was born in Paris in 1720, one of Julien Le Roy's four sons . As the son of a royal watchmaker, he received an excellent education. His father taught him the basics of mechanics and then sent him to England, where Jean-Baptiste studied literature and was tutored by the respected natural philosopher and scientist John Theophilus Desaguliers .

In October 1747, Le Roy was hired to write the Encyclopédie , three days after Diderot and d'Alembert took over the editorship. Le Roy's subject areas as a contributor to the Encyclopédie included watchmaking , locksmithing and the description of mathematical instruments . Under the author's abbreviation “T” he contributed more than 130 articles, whereby Kafker states that contributions such as “Coup foudroyant”, “Echappement” and “Electromètre” were based on the current state of research at the time - including Le Roy's own. Most of the watchmaking contributions in the first seven volumes of the Encyclopédie were made by Le Roy and were rated “very well done” by Bertrand Gille. In later volumes, Le Roy's contributions are sparse, but he contributed the article "Télescope" even after the work was placed on the Index Librorum Prohibitorum in 1759 .

As a scientist, Le Roy worked on subjects as diverse as street lighting, vaccination against smallpox , hospital hygiene, cleaning Paris' drinking water, and hundreds of other projects. Some of his contemporaries, such as the Swedish astronomer and mathematician Anders Johan Lexell , accused him of amateurism . Between 1778 and 1780 he represented against Louis Daubenton and some other members of the Académie royale des sciences Franz Anton Mesmer's teaching of animal magnetism , but then belonged in 1784 together with Jean-Sylvain Bailly , Joseph-Ignace Guillotin , Benjamin Franklin , Antoine Laurent de Lavoisier and others to a commission that rejected Mesmer's theories.

Le Roy's research on electricity is of particular importance . Together with Patrick d'Arcy (1725–1779), he constructed the first electrometer in 1749 , a device for detecting electrical charges and voltages. He supported Franklin in the controversy as to whether electricity consists of the simultaneous inflow (“affluence”) and outflow (“effluence”) of electrical matter, as claimed by Jean-Antoine Nollet , or of a current, as represented by Benjamin Franklin. He also experimented with lightning rods and the use of electricity in the treatment of diseases. Jean Daujat describes Le Roy in his work Origines et formation de la théorie des phénomènes électiques et magnétiques from 1945 as one of the "great names of electricity in the 18th century".

Le Roy was a close friend of Benjamin Franklin and corresponded with him for over 40 years. During Franklin's stay as a diplomat in France between 1776 and 1785, the two often played chess together, ate together, and talked about electricity and other scientific subjects. Apparently Franklin was also inclined to Le Roy's wife, a former Baroness von Messey, whom he called "ma petite femme de poche". Le Roy himself neglected his wife, had various affairs and finally separated from her a few years before the outbreak of the French Revolution .

Le Roy actively supported the revolution - presumably mainly because it offered so many opportunities for practical reform, such as the standardization of weights and measures. In 1789 he became politically active in his local Paris district, in 1790 he tested new weapons on behalf of the government and between 1791 and 1796 he was a member of the Bureau de consultation des arts et métiers , which he temporarily chaired. During the reign of terror , Le Roy was a member of the armaments committee. However, he was not positive about all developments in the revolution. He lamented the premature end of the constitution of 1791 and the execution of his colleague Lavoisier , which he had tried to prevent to the last.

After the dissolution of the royal academies in 1795, Le Roy was elected a member of the Institut de France , the umbrella organization of the new, now state academies. He died in Paris five years later.

literature

swell
  • On Le Roy's work at the Académie des sciences: Archives de l'Académie des sciences de l'institut de France, dossier personnel de Jean-Baptiste Le Roy.
  • Some of Le Roy's letters have been published in: Leonard W. Labaree [u. a.] (ed.), The Papers of Benjamin Franklin , New Haven 1959ff., passim , and in Julian P. Boyd and Charles T. Cullen (ed.), The Papers of Thomas Jefferson , Princeton 1950ff., passim.
Representations
  • "Le Roy, Jean-Baptiste", in: Frank Arthur Kafker, The encyclopedists as individuals: a biographical dictionary of the authors of the Encyclopédie , Oxford 1988, ISBN 0-7294-0368-8 , pp. 219-222.
  • Louis S. Greenbaum: Tempest in the Academy: Jean-Baptiste Le Roy, the Paris Academy of Sciences and the Project of a new Hôtel-Dieu ' , in: Archives internationales d'histoire des sciences 24 (1974), p. 122– 140

Web links

Remarks

  1. ^ List of members since 1666: Letter L. Académie des sciences, accessed on January 12, 2020 (French).
  2. ↑ Both d'Alembert and Diderot had personal contacts with the Le Roys family. D'Alembert knew Jean-Baptiste's father and Diderot was saved by Jean-Baptiste or one of his brothers at a party from hooking up with the hostess, who may have had a venereal disease. Kafker, The encyclopedists as individuals , p. 219 and footnote 1 on p. 222.
  3. ↑ Kafker, The encyclopedists as worth individuals , S. 220th
  4. ↑ "fort bien faites", Bertrand Gille, L'Encyclopédie, dictionnaire technique , in: L'Encyclopédie et le progres des sciences et des techniques, ed. by Suzanne Delorme and René Taton, Paris 1952, p. 201.
  5. ↑ “On dit qu'il est habile Physicien, mail il ne paroit pas avoir le jugement très profond et subtle. Malgré cela il ne manque jamais d'avoir quelque chose à produire à l'Académie, quelquefois aussi des grandes bagatelles. ", Arthur Birembaut, L'Académie royale des sciences en 1780 vue par l'astronome suédois Lexell (1740–1784) , in: Revue d'histoire des sciences et de leurs applications 10 (1957), p. 160, here cited from Kafker, The encyclopedists as individuals , p. 220.
  6. ↑ “un des grands noms de l'électricité au XVIIIe siècle”, Jean Daujat, Origines et formation de la théorie des phénomènes électiques et magnétiques , Paris 1945, iii.433, here quoted from Kafker, The encyclopedists as individuals , p. 221 .
  7. ↑ Kafker, The encyclopedists as worth individuals , S. 221st
personal data
SURNAME Le Roy, Jean-Baptiste
BRIEF DESCRIPTION French polymath, director of the Académie royale des sciences and a major contributor to the Encyclopédie
DATE OF BIRTH August 15, 1720
PLACE OF BIRTH Paris
DATE OF DEATH January 21, 1800
Place of death Paris