Jean-Étienne Guettard

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Jean-Étienne Guettard

Jean-Étienne Guettard (born September 22, 1715 in Étampes , Île-de-France, † January 6 or 7, 1786 in Paris ) was a French doctor, naturalist, cartographer and mineralogist . Its official botanical author's abbreviation is “ Guett. "

Life

Guettard was a grandson of François Descurain Jr. (1658–1740) from Étampes near Paris. The daughter of François Descurain jr. was Marie-Françoise Descurain; on July 26, 1706 she married Jean Guettard (1691–1742), the father of J.É. Guettard.

J. É. Guettard attended school in Étampes, near Montargis . However, this was of less impact on his later interests, he was more under the influence of his maternal grandfather, François Descurain Jr., a pharmacist and amateur botanist and his friend Bernard de Jussieu (1699–1777). He studied medicine in Paris and became Frequentior hodie quam olim febris maligna? PhD in 1741.

In the same year 1741 he was curator of the scientific collection of the French scientist René-Antoine Ferchault de Réaumur (1683-1757). During this collaboration with de Réaumur, a knowledgeable botanist and zoologist, he got to know the investigation methods of the mineral world extensively and techniques for the investigation and collection of samples and their documentation. Then in 1742 he became a member of the Medical Faculty of Paris.

After his studies and doctorate in medicine, he worked from 1747 on under the royal patronage of Louis I. de Bourbon , duc d'Orléans (1703-1752). During this period from 1747 to 1752 he was the médecin botanist of the French Prince Louis I de Bourbon, duc d'Orléans, and as part of his activities also the custodian of his natural history collection. After the death of the duc d'Orléans (1752) he continued this work under the patronage of his son Louis Philippe I de Bourbon, duc d'Orléans (1725-1785).

J. É. Guettard traveled extensively in France, but also the Netherlands, Italy, Switzerland, Poland and was particularly interested in the geology of these countries. But questions about mineral resources and mining are also important.

Scientific achievements

In addition to botany, he was intensely interested in geological and mineralogical questions. He discovered the volcanic nature of the Auvergne region in France. Henri-Léonard Bertin (1720–1792) as minister and state secretary also responsible for mining gave him the task of preparing a geological survey of France and mapping the mineralogical distributions. To this end, worked from 1766 with the French chemist Antoine Lavoisier (1743–1794). He is considered a pioneer of geological mapping, the Atlas minéralogique de la France was the first atlas to record and map the geological features of France. The collaboration between Guettard and Lavoisier had actually started before this point in time, and they took part in the various excursions together, for example their geological excursions to Alsace , Lorraine and Franche-Comté in 1767. By 1777 they had around 200 cards created. In addition to many other achievements J.-É. Guettards are his identification of trilobites in the shales of Anjou and his discovery of French kaolin - deposits . On his trip to Normandy in 1746 , he discovered French deposits of kaolin, an indispensable raw material for the manufacture of porcelain Mémoire et carte minéralogique sur la nature des terreins qui traversent la France et l'Angleterre (1765–1766). His mapping work was continued by the Inspector General for Mining Antoine-Grimald Monnet , who published the Atlas Mineralogique de France in 1780 .

As a botanist, he defended the Linnaean system against its many critics.

J.É. Guettard and volcanism

In 1751 he traveled to the Auvergne (see also Massif central ) , accompanied by his friend Chrétien-Guillaume de Lamoignon de Malesherbes (1721–1794 ). During this trip, J.É. Guettard that volcanic rocks were often used for the construction of public roads and apartments, he examined the quarries and found that the entire region was volcanic. He described this discovery in his Mémoires sur quelques montagnes de France qui ont été des volcans (1752).

In the well-known controversy over the nature of the basalt columns, J.É. Guettard initially believed that these formations were not of volcanic origin. However, after traveling to Italy in 1771 and 1772 and visiting the Montpellier area in 1771, he began to doubt the Neptunist position. The accuracy of his doubts was confirmed when he explored the area of ​​Montélimar in Dauphiné in 1775. The changed opinion about the origin of the basalt columns found its expression in the Mémoires sur la minéralogie du Dauphiné (1779).

The theory of the Neptunists coincided best with the history of creation and, as a “conservative” theory, found ample supporters. However, when the lava was classified as basalt and the volcanic origin of all basaltic rocks was recognized, the plutonists won.

Honors

He was a member of the Académie des Sciences in Paris.

Works

Web links

Individual evidence

  1. ↑ gw2.geneanet.org Genealogy
  2. ↑ mnhn.fr (PDF; 8.8 MB) Detailed biography with images (French)
  3. ↑ Carl von Linné: Heptandria. Guettarda . In: Species Plantarum , Volume 2, 1753, p. 991 (at Gallica)
  4. ^ Guettardite Mindat
  5. ^ List of members since 1666: Letter G. Académie des sciences, accessed on November 20, 2019 (French).
personal data
SURNAME Guettard, Jean-Etienne
BRIEF DESCRIPTION French physician, naturalist, cartographer, and mineralogist
DATE OF BIRTH September 22, 1715
PLACE OF BIRTH Étampes Île-de-France
DATE OF DEATH January 6, 1786 or January 7, 1786
Place of death Paris