René-Antoine Ferchault de Réaumur
French scientist, 1683-1757
Réaumur contributed to many different fields, especially the study of insects. He introduced the Réaumur temperature scale. The Réaumur scale saw widespread use in Europe, particularly in France and Germany as well as Russia, as referenced in works of Dostoyevsky, Tolstoy, and Nabokov. By the 1790s, France chose the Celsius scale for the metric system over the Réaumur measurements, but it was used in some parts of Europe until at least the mid-19th century. Its only modern use is in the measuring of milk temperature in cheese production.
Source: Wikipedia
naturalist (1683-1757). Autograph letter signed. Paris. 4to. 1 p.
$ 3,658 / 3.200 €
(103521)
In this remarkable scientific letter titled “L’action directe ou indirecte du soleil sur le thermomètre,” the French naturalist and physicist René-Antoine Ferchault de Réaumur (1683–1757) discusses the effects of sunlight on temperature measurement. He writes appreciatively to a fellow scientist: "On ne s'étoit point avisé, Monsieur, d'examiner le rapport de l'effet produit sur le thermomètre par l'action directe des rayons du soleil, avec celui qui n'a pour cause que l'attouchement d'un air dans lequel il n'y a que des rayons réfléchis.
Mais je ne suis point surpris que vous songiez à faire des observations et des expériences curieuses et utiles auxquelles d'autres n'avoient pas pensé..." Réaumur goes on to express his gratitude for the flattering mention made of him in the recipient’s dissertation, while modestly attributing it to friendship rather than merit: "Je le suis aussi peu de la mention flatteuse que vous avez faite de moy dans la dissertation pour laquelle je vous dois et je vous fais des remerciements, sachant que votre amitié pour moy est très capable de vous faire croire que les éloges dont elle me voudroit digne me sont dûs ; je mérite au moins les sentiments qui vous séduisent en ma faveur par le parfait et respectueux attachement avec lequel j'ai l'honneur d'être votre très humble et obéissant serviteur..." This letter highlights Réaumur’s deep interest in the physics of heat and the measurement of temperature. He was the inventor of the alcohol thermometer and one of the pioneers in establishing consistent temperature scales. The recipient may have been the physicist Jean-Pierre Christin (1683–1755), one of the inventors of the mercury thermometer, who, in 1747, presented to the Académie de Lyon his own research on the direct and indirect effects of solar heat on thermometers—a topic closely related to Réaumur’s experiments. Provenance: Max Thorek, Chicago (stamped)..
Naturforscher (1683-1757). Document signed ("de Reaumur"). [Paris]. 20.02.1743. 1 S. Gr.-8vo.
$ 3,200 / 2.800 €
(32897/BN27582)
In French: “By order of the Academy we have read the Letters Patent of Oct. 26 1742 by which the King grants to Sir Francois Fresneau, former surgeon on His Majesty’s ships, the exclusive privilege of constructing, selling, and distributing, for a period of 30 years, a stove invented by him for different kitchen procedures using a single flame [...] we declare that this stove can be very useful, provided that the author does not multiply its operations excessively [...]”. Signed by de Reaumur, with counter-signatures by fellow members of the Academy of Sciences Jean Hellot and Louis-Léon Pajot d’Onsenbray.
Also endorsed in the upper right by Francois Fresneau, providing the date. In very good condition, with intersecting folds. Uniform toning, with a few spots and ink flecks along bottom. A rare association of prominent scientists of the period..