Guillaume-François Rouelle

Guillaume- François Rouelle ( born September 15, 1703 Mathieu, † August 3, 1770 in Passy (Paris) ) was a French chemist.

Life

The son of Jacques Rouelle and his wife Marie Bougon had grown up in rural gutgestellten family relationships and is said to have developed in early childhood a great curiosity. This curiosity aroused in him the urge to continually develop. His younger brother was Hilaire -Marin Rouelle and also a chemist. After an education at the Collège du Bois in Caen then he began to study at the University of Caen. Here he had devoted himself to the medical school especially in chemistry.

His studies he continued in Paris. He entered 1730 in the former laboratory of Nicolas Lemery, working under a native of Germany pharmacist Johann Gottlob Spitzley ( 1690-1750 ). The laboratory was in the Rue Saint- André-des -Arts. Here he worked for seven years.

Later, from 1737, he established himself as a pharmacist and to set up its own research laboratory at Place Maubert. Through their experiments and lectures he had acquired such a reputation that he, inter alia, by the recommendation of Georges- Louis Leclerc de Buffon in 1743 the demonstrator, démonstrateur of Chemistry at the Jardin du Roi was appointed. After the death of the chemist Gilles -François Boulduc (1675-1741) was vacant this position.

There, in the Jardin de Plantes, under the " Pointing " by the very Guillaume- François was an exact difference between teachers, in the sense of actually " reading ends ," said by Professor Louis -Claude Bourdelin (1696-177), and the demonstrators, Rouelle, taken or institutionalized. In a report from the Correspondance littéraire from August 1770 this situation was reproduced; Louis -Claude Bourdelin had finished his lecture, he concluded with the phrase:

" [ ... ] Comme le monsieur démonstrateur va vous le prouver par ses expériences [ ... ] "

" [ ... ] Comme ... How do you monsieur the Lord demonstrator will prove by his experiments. "

On the other hand, opened its Rouelle demonstration or experiments with the following words:

" [ ... ] Messieurs, tout ce que monsieur le professeur vient de vous dire est et absurd faux, comme je vais vous le prouver. [ ... ] "

" [ ... ] Gentlemen, everything the professor said is absurd and wrong, as I will prove it to you immediately. "

His courses, demonstrations and lectures were attended by numerous members of the intellectual elite, including Denis Diderot, d' Holbach, Paul Henri Thiry, Antoine Laurent de Lavoisier and Antoine Parmentier.

On May 6, 1744 Rouelle was, adjoint - chimiste appointed to the Académie royale des sciences to chemical adjuncts, which he then became an associate member from 1752. The year 1746 was a parade of his laboratory in the Rue Jacob, joined at the corner of the Rue des Deux- Anges, where he continued his previous activities. He also filed an application for inclusion in the community of Pharmacists of Paris, the apothicaires communauté de Paris. He rejected the position of the first pharmacist, premier apothicaire of Louis XV. from, instead he took over the job of the Inspector General of Pharmacy, Inspecteur général de la pharmacie at the Hôtel- Dieu. Rouelle was married to Anne Mondon, they had twelve children. Her daughter Françoise- Julie Rouelle (about 1752-1788 ) married in 1771 the chemist Jean Darcet ( 1724-1801 ).

In 1768 he resigned his professorship. He was also a member of the Academy of Sciences in Erfurt profit and the Royal Swedish Academy of Sciences.

Work

Rouelle is to be regarded as a forerunner of modern chemistry in France. Through his lectures, he was the best chemist who worked in France at the end of the 18th century, from. For example, Antoine Laurent de Lavoisier was from 1761 one of his students. But Denis Diderot heard in the period 1754 to 1757 his lectures regularly in the Jardin du Roi.Ein further encyclopedist Paul Henri Thiry d' Holbach sat almost at the same time with the content of his lectures and chemistry apart.

By distillation of tin chloride and alcohol, he discovered in 1759 the slight salt ether ( hydrochloric ether ), examined tartrate salts and the effects of sulfuric acid ( H2SO4) on fats and essential oils. He was able to define the concept of salt exact Through his research, which he divided it into neutral, acidic and basic salts. He already used the term in 1754 as the opposite of acid base.

He developed a general theory of salts, but he shared the neutral salts into two broad classes, depending on the different amounts of water which was necessary to bring them into solution. These main classes have now been further subdivided; later further methods for classification about the shape of the crystals, the way has their formation, etc. time. Eventually led the schema in two main classes, divided into six sub-classes and then the acid and base groups which they contain, respectively.

Rouelle was a supporter of the phlogiston theory of Georg Ernst steel whose thoughts he shared. Nevertheless, the phlogiston concept of steel and Johann Juncker learns by Rouelle a reassessment. For Rouelle phlogiston not like in the contemplation of steel was only a " Fire rag " and one aspect of "earth" or " earthen " terra pinguis or greasy earth, they corresponded to the oily liquid of the alchemists, the oily the substances, sulphurous and would lend flammable property.

Writings (selection )

• Memoire sur les Sels neutres, Dans une division propose lequel on méthodique de ces Sels, qui les moyens facilite pour parvenir à la théorie de leur crystal lization. In: Histoire de l' Académie Royale des Sciences. Paris 1744, pp. 353-364 (online).
• Sur le sel marin (premiere partie. ) De la crystal lization du Sel marin. In: Histoire de l' Académie Royale des Sciences. Paris 1745, pp. 57-79 (online).
• Sur L' inflammation de l' huile de Térébinthine, par l' acide nitreux pure, suivant le procédé de Borrichius; Et sur ​​l' inflammation de plusieurs huiles essential, & par avec le expression méme acidic, avec l' acide & conjointement vitriolique. In: Histoire de l' Académie Royale des Sciences. Paris 1747, pp. 34-56 (online).
• Sur les Embaumemens of Egyptiens, Premier Mémoire Dans lequel on fait voir que les fondemens de l'art of Embaumemens égyptiens sont en partie Contenus dans la description, qu'en a donné Hérodote, où l' on déterminé & quelles sont matières qu ' on employoit dans ces Embaumemens. In: Histoire de l' Académie Royale des Sciences. Paris 1750, p.123 -150 (online).
• Mémoire sur les Sels neutres, Dan lequel on fait deux nouvelles connoitre classes de Sels neutres, & l' le Développement on phénomène singulier de l' acide dans ces excès d' sels. In: Histoire de l' Académie Royale des Sciences. Paris 1754, S.572 -588 (online).