At 10:38 -0400 01/04/18, James R. Frysinger wrote:
>I have never used the Reaumur scale and know nothing about it.
>
>Jim
René Antoine Ferchault de Réaumur (1683 - 1757) was a scientist
typical of the "Siècles des Lumières", i.e. he was excellent in all
matters : mathematics ("Mémoires Géométriques, 1708), metallurgist
("l'Art de convertir le fer forgé en acier", how to convert iron into
steel, 1722), biologist, glass-making, entomologist ("Mémoires pour
servir à l'histoire des insectes", 1737 - 1748).
In one of his experiments (artificial incubation of chicken eggs),
Réaumur needed to control very accurately the temperature, but was
not happy with the accuracy of the then available thermometers.
Therefore, in 1730-1731, he developed a new type of thermometer, with
alcohol as dilatating liquid. He used molten ice to define the cold
point, giving it the value 0, and boiling water for the hot point,
with the value 80. I could not find out why 80.
The "Réaumur scale" was quite popular in Europe in the XVIII - XIX th
centuries, up to the beginning of XXth century in Central Europa.
Lavoisier and Arago sometimes used the Réaumur scale. There is at the
excellent "Musée des Arts et Métiers" in Paris a collection of
thermometers with the Réaumur scale or a dual Réaumur/Celsius scale.
Louis
