››Convert degree Rømer to degree Delisle

 degree Rømer Delisle

How many degree Rømer in 1 Delisle? The answer is -0.35.
We assume you are converting between degree Rømer and degree Delisle.
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degree Rømer or Delisle
The SI base unit for temperature is the kelvin.
1 kelvin is equal to 0.525 degree Rømer, or -1.5 Delisle.
Note that rounding errors may occur, so always check the results.
Use this page to learn how to convert between degrees Rømer and degrees Delisle.
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››Definition: Romer

Rømer is a disused temperature scale named after the Danish astronomer Ole Christensen Rømer, who proposed it in 1701.

In this scale, the zero was initially set using freezing brine. The boiling point of water was defined as 60 degrees. Rømer then saw that the freezing point of water fell at roughly one eighth of that value (7.5 degrees), so he used that value as the other fixed point. Thus the unit of this scale, a Rømer degree, is 40/21sts of a kelvin (or of a Celsius degree). The symbol is sometimes given as °R, but since that is also sometimes used for the Rankine scale, the other symbol °Rø is to be preferred. The name should not be confused with Réaumur.

Daniel Gabriel Fahrenheit learned of Rømer's work and visited him in 1708; he improved on the scale, increasing the number of divisions by a factor of four and eventually establishing what is now known as the Fahrenheit scale, in 1724.

››Definition: Delisle

The Delisle scale is a temperature scale invented in 1732 by the French astronomer Joseph-Nicolas Delisle (1688–1768). It is similar to that of Réaumur. Delisle was the author of Mémoires pour servir à l'histoire et aux progrès de l'Astronomie, de la Géographie et de la Physique (1738).

He had been invited to Russia by Peter the Great. In 1732 he built a thermometer that used mercury as a working fluid. Delisle chose his scale using the temperature of boiling water as the fixed zero point and measured the contraction of the mercury (with lower temperatures) in hundred-thousandths. The Celsius scale too originally ran from zero for boiling water down to 100 for freezing water. This was reversed to its modern order some time after his death, in part at the instigation of Daniel Ekström, the manufacturer of most of the thermometers used by Celsius.

The Delisle thermometers usually had 2400 graduations, appropriate to the winter in St. Petersburg. In 1738 Josias Weitbrecht (1702–1747) recalibrated the Delisle thermometer with 0 degrees as the boiling point and 150 degrees as the freezing point of water. The Delisle thermometer remained in use for almost 100 years in Russia.

Thus, the unit of this scale, the Delisle degree (sometimes spelled de Lisle), is -2/3 of a kelvin (or a degree Celsius) and absolute zero is at 559.725 Delisle degrees.

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