Jean-Étienne Guettard

Jean- Étienne Guettard ( born September 22, 1715 in Etampes, Ile -de -France; † 6 or January 7, 1786 in Paris) was a French physician, naturalist, cartographer, and mineralogist. Its official botanical author abbreviation is " Guett. "

Life

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

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

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

After his studies and doctorate in medicine, he worked from 1747 to under the royal patronage of Louis I de Bourbon, duc d' Orléans ( 1703-1752 ). During this period from 1747 to 1752 he was médecin botaniste the French prince Louis I de Bourbon, duc d' Orléans, and in the course of its activities and guardians whose natural history collection. After the death of the duc d' Orléans ( 1752) he continued that work under the auspices of his son Louis- Philippe I ( 1725-1785 ).

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

Scientific achievements

In addition to the botany he was interested intensive geological and mineralogical questions. He discovered the volcanic nature of the Auvergne region of France. Henri -Leonard Bertin (1720-1792) and as Minister of State also responsible for mining gave him the order to prepare a geological survey of France and to map the mineralogical distributions. To this end, worked from 1766 to the French chemist Antoine Lavoisier ( 1743-1794 ) together. He is considered a pioneer of geological mapping, the Atlas mineralogique de la France was the first atlas of the recorded geological features of France and charted. The cooperation of Guettard and Lavoisier had started actually before that date, and the various excursions they took together true about their geological excursions in the Alsace, Lorraine and Franche- Comté in after 1767. By 1777 they had approximately 200 cards created. Among many other achievements J.-E. Guettards are also his identification of trilobites in the shales of Anjou and his discovery of French kaolin deposits. On his journey in 1746 in Normandy, he discovered French deposits of kaolin, an essential raw material for the manufacture of porcelain Mémoire sur la nature et carte mineralogique of terreins traversent qui la France et l' Angleterre ( 1765-1766 ).

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

J. E. Guettard and volcanism

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

In the well-known controversy about the nature of the basalt columns J. E. supported Guettard first the view that these formations are not of volcanic origin. However, after his travels to Italy in the years 1771 and 1772 and the visit around Montpellier in 1771, he joined the neptunistischen position to doubt. The correctness of his doubting were confirmed when he explored the area in 1775 from Montelimar in Dauphiné. The amended opinion on the origin of basalt columns found its expression in the Mémoires sur la min éralogie du Dauphiné (1779 ).

The theory of Neptunists coincided best with the creation story and found a " conservative " theory plenty of followers. However, when the lava was classified as basalt and basaltic rocks of volcanic origin of all had been detected, the Plutonists carried the day.

Honors

• Carl Linnaeus named in his honor the plant genus Guettarda from the family of Rubiaceae ( Rubiaceae ).
• A 1966 newly discovered mineral named after him Guettardit.

Works

• Observations sur les plantes (Durand, Paris, deux volumes, 1747 ), où il cite ses observations et celles de son grand- père, Descurain, pharmacien à Etampes.
• Carte mineralogique, Où l' on voit la Nature of terreins du Canada et de la Louisiane. Dressée par Philippe Buache de l' Ac. les recherches sur des Sciences et pour un Mémoire de Mr de la même Guettard Acadadémie. In 1752. ( C'est la première de l' Amérique mineralogique carte du Nord. )
• Mémoires sur des sciences et arts différentes parties (L. Prault, Paris, trois volumes, 1768-1770 ).
• Il l' Histoire traduit naturelle.de Pline l' Ancien (Paris, douze volumes, 1771-1782 ).
• Mémoires sur la minéralogie du Dauphiné ( imprimerie de Clousier, Paris, deux volumes, 1779).
• Atlas et description minéralogiques de la France, entrepris par ordre du Roi ( Didot l' aîné, Paris, 1780).