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Réaumur

From Biocrawler, the free encyclopedia.

This article is about the temperature scale. Réaumur is also the name of a commune in the Vendée département, in France; see Réaumur.

The degree Réaumur is a unit of temperature named after René Antoine Ferchault de Réaumur, who first proposed it in 1731. The freezing point of water is 0 degrees Réaumur, the boiling point 80 degrees Réaumur. Hence a degree Reaumur is 1.25 degrees Celsius or kelvins. The Réaumur temperature scale is also known as the "division octogesimale" or "octogesimal division".

Réaumur's thermometer was constructed on the principle of taking the freezing point of water as 0°, and graduating the tube into degrees each of which was one-thousandth of the volume contained by the bulb and tube up to the zero mark. It was the dilatability of the particular quality of alcohol employed which made the boiling point of water 80°; and mercurial thermometers the stems of which are graduated into eighty equal parts between the freezing and boiling points of water are not Réaumur thermometers in anything but name.

The Réaumur scale saw widespread use in Europe, particularly in France and Germany, but was eventually replaced by the Celsius scale. Today it is of historical significance.

Degree Réaumur
Kelvin	[K] = [°Ré] · 5/4 + 273.15	[°Ré] = ([K] − 273.15) · 4/5
Celsius	[°C] = [°Ré] · 5/4	[°Ré] = [°C] · 4/5
Fahrenheit	[°F] = [°Ré] · 9/4 + 32	[°Ré] = ([°F] − 32) · 4/9
Rankine	[°Ra] = [°Ré] · 9/4 + 491.67	[°Ré] = ([°Ra] − 491.67) · 4/9
Newton	[°N] = [°Ré] · 33/80	[°Ré] = [°N] · 80/33
Rømer	[°Rø] = [°Ré] · 21/32 + 7.5	[°Ré] = ([°Rø] − 7.5) · 32/21
Delisle	[°De] = (80 − [°Ré]) · 15/8	[°Ré] = 80 − [°De] · 8/15