Louis-Guillaume Le Monnier (sometimes written as Lemonnier) (27 June 1717 – 7 September 1799) was a French

natural scientist Natural science is one of the branches of science concerned with the description, understanding and prediction of natural phenomena, based on empirical evidence from observation and experimentation. Mechanisms such as peer review and repea ...

and contributor to the

Encyclopédie ou Dictionnaire raisonné des sciences, des arts et des métiers ''Encyclopédie, ou dictionnaire raisonné des sciences, des arts et des métiers'' (English: ''Encyclopedia, or a Systematic Dictionary of the Sciences, Arts, and Crafts''), better known as ''Encyclopédie'', was a general encyclopedia publi ...

''.Frank A. Kafker: ''Notices sur les auteurs des dix-sept volumes de « discours » de l'Encyclopédie.'' Recherches sur Diderot et sur l'Encyclopédie Année (1989) Volume 7 Numéro 7 p. 147
/ref> He was born near

Vire Vire () is a town and a former commune in the Calvados department in the Normandy region in northwestern France. On 1 January 2016, it was merged into the new commune of Vire Normandie. Geography The town is located on the river Vire. Much of i ...

as the son of Pierre Le Monnier (1675–1757), who was a scientist himself and a member of the French Academy of Sciences. Cuvier, G.: '' Éloge historique de Lemmonier'', 7 October 1800. Louis-Guillaume's older brother was the astronomer

Pierre Charles Le Monnier Pierre Charles Le Monnier (; 23 November 1715 – 3 April 1799) was a French astronomer. His name is sometimes given as Lemonnier. Biography Le Monnier was born in Paris, where his father Pierre (1675–1757), also an astronomer, was professo ...

.Crépel, P.:
La 'physique' dans ''l'Encyclopédie''
, ''Recherches sur Diderot et sur l'Encyclopédie, numéro 40–41'', 2006. ISSN 1955-2416. Louis-Guillaume Le Monnier worked in physics, geology, medicine, and botany. In 1739 he accompanied the expedition of César-François Cassini de Thury and

Nicolas Louis de Lacaille Abbé Nicolas-Louis de Lacaille (; 15 March 171321 March 1762), formerly sometimes spelled de la Caille, was a French astronomer and geodesist who named 14 out of the 88 constellations. From 1750 to 1754, he studied the sky at the Cape of Goo ...

to extend the Meridian of Paris and documented mines and the geology and botany along the route. In the same year, he also began working at the hospital of

Saint Germain en Laye Saint-Germain-en-Laye () is a commune in the Yvelines department in the Île-de-France in north-central France. It is located in the western suburbs of Paris, from the centre of Paris. Inhabitants are called ''Saint-Germanois'' or ''Saint-Ge ...

as a physician. He researched electrical phenomena, sending a current from a

Leyden jar A Leyden jar (or Leiden jar, or archaically, sometimes Kleistian jar) is an electrical component that stores a high-voltage electric charge (from an external source) between electrical conductors on the inside and outside of a glass jar. It typ ...

through a wire 950

toise A toise (; symbol: T) is a unit of measure for length, area and volume originating in pre-revolutionary France. In North America, it was used in colonial French establishments in early New France, French Louisiana (''Louisiane''), Acadia (''Acadi ...

s (about 1,850 m) long and concluded that electricity propagated "instantaneously" in the wire.Le Monnier, L.-G.: "Recherches sur la Communication de l'Electricité",
Histoire de l'Académie royale des sciences (1746)
', pp. 477ff. Later research of his on electrical phenomena was concerned with

thunderstorm A thunderstorm, also known as an electrical storm or a lightning storm, is a storm characterized by the presence of lightning and its acoustic effect on the Earth's atmosphere, known as thunder. Relatively weak thunderstorms are some ...

s and the " fair weather condition".Le Monnier, L.-G.: "Observations sur l'Electricité de l'Air",
Histoire de l'Académie royale des sciences (1752)
', pp. 233ff. Like his father and his brother before him, Louis-Guillaume became a member of the ''Académie des sciences'' on 3 July 1743, and was elected a fellow of the

Royal Society The Royal Society, formally The Royal Society of London for Improving Natural Knowledge, is a learned society and the United Kingdom's national academy of sciences. The society fulfils a number of roles: promoting science and its benefits, re ...

on 7 February 1745,The Royal Society
Lists of Fellows of the Royal Society 1660 – 2007
URL. Retrieved 19 February 2010. of which his brother also was a member. On 30 June 1746, one year after his brother, he also became a member of the

Prussian Academy of Sciences The Royal Prussian Academy of Sciences (german: Königlich-Preußische Akademie der Wissenschaften) was an academy established in Berlin, Germany on 11 July 1700, four years after the Prussian Academy of Arts, or "Arts Academy," to which "Berlin ...

.Berlin-Brandenburgische Akademie der Wissenschaften
Mitglieder der Vorgänger-Akademien
URL. Retrieved 19 February 2010. With Claude Richard he was one of the original organizers of

Louis XV Louis XV (15 February 1710 – 10 May 1774), known as Louis the Beloved (french: le Bien-Aimé), was King of France from 1 September 1715 until his death in 1774. He succeeded his great-grandfather Louis XIV at the age of five. Until he reached ...

's botanic collection at

Petit Trianon The Petit Trianon (; French for "small Trianon") is a Neoclassical style château located on the grounds of the Palace of Versailles in Versailles, France. It was built between 1762 and 1768 during the reign of King Louis XV of France. ...

, an undertaking quickly joined by

Bernard de Jussieu Bernard de Jussieu (; 17 August 1699 – 6 November 1777) was a French naturalist, younger brother of Antoine de Jussieu. Bernard de Jussieu was born in Lyon. He took a medical degree at Montpellier and began practice in 1720, but finding the w ...

. Lemonnier was appointed professor of botany at the Jardin du Roi (later the Jardin des Plantes) in 1759, filling a spot left by the death of

's brother Antoine in April of the previous year. In 1786 he was succeeded as professor of botany by

René Louiche Desfontaines René Louiche Desfontaines (14 February 1750 – 16 November 1833) was a French botanist. Desfontaines was born near Tremblay in Brittany. He attended the Collège de Rennes and in 1773 went to Paris to study medicine. His interest in bot ...

.French National Archives
Jardin du Roi: Botanistes
URL. Retrieved 16 February 2010. For Diderot's ''

Encyclopédie ''Encyclopédie, ou dictionnaire raisonné des sciences, des arts et des métiers'' (English: ''Encyclopedia, or a Systematic Dictionary of the Sciences, Arts, and Crafts''), better known as ''Encyclopédie'', was a general encyclopedia publis ...

'' he wrote several entries, among them "Electricité", "Magnétisme", "Aimant" (

Magnet A magnet is a material or object that produces a magnetic field. This magnetic field is invisible but is responsible for the most notable property of a magnet: a force that pulls on other ferromagnetic materials, such as iron, steel, nicke ...

), and "Aiguille aimantée" (

Compass needle A compass is a device that shows the cardinal directions used for navigation and geographic orientation. It commonly consists of a magnetized needle or other element, such as a compass card or compass rose, which can pivot to align itself with ...

).''L'Encyclopédie'': " Aiguille aimantée". After 1759, he stopped publishing, though.Wronecki, M.-H.; Blondel, Ch.:
Le Monnier (ou Lemonnier), Louis-Guillaume (1717–1799)
, ''Ampère et l'histoire de l'électricité'', CNRS, 2005. URL. Retrieved 16 February 2010. In his later career, he became in 1770 "Premier médecin ordinaire" and in 1788 "Premier médecin du Roi". His lover was

Marie Louise de Rohan Marie may refer to: People Name * Marie (given name) * Marie (Japanese given name) * Marie (murder victim), girl who was killed in Florida after being pushed in front of a moving vehicle in 1973 * Marie (died 1759), an enslaved Cree person in Tr ...

, ''Madame de Marsan'', future

Governess of the Children of France The Governess of the Children of France (sometimes the Governess of the Royal Children) was office at the royal French court during pre-Revolutionary France and the Bourbon Restoration. She was charged with the education of the children and grandchi ...

. His publications include: *''Leçons de physique expérimentale, sur l'équilibre des liqueurs et sur la nature et les propriétés de l'air'' (1742). *''Observations d'histoire naturelle faites dans les provinces méridionales de France, pendant l'année 1739'' (1744). *''Recherches sur la Communication de l'Electricité'' (1746). *''Observations sur l'Electricité de l'Air'' (1752).

References

{{DEFAULTSORT:Lemonnier, Louis-Guillaume 1717 births 1799 deaths Members of the French Academy of Sciences Contributors to the Encyclopédie (1751–1772) Fellows of the Royal Society Scientists from Paris 18th-century French botanists 18th-century French physicists