Delisle to Fahrenheit (°De to °F)
1 degree Delisle equals 210.8 degrees Fahrenheit.
How to convert degrees Delisle to degrees Fahrenheit
Converting degrees Delisle to degrees Fahrenheit is not a simple multiplication, so use the formula below.
°F = °De × -1.2 + 212
Example: 10 degrees Delisle = 200 degrees Fahrenheit.
Temperature scales have different zero points, so converting is not just multiplication. Differences in degrees convert differently from absolute readings.
About these units
Degree Delisle (°De)
An inverted scale devised by Joseph-Nicolas Delisle in 1732 and later fixed with water boiling at 0° and freezing at 150°, so temperatures rise as it gets colder. Used in Russia for roughly a century.
Temperatures on the Delisle scale rise as things get colder, a reversal found in very few thermometer systems. Joseph-Nicolas Delisle, a French astronomer, built a mercury thermometer in 1732 with zero at the boiling point of water and measured the contraction of the mercury in hundred-thousandths. Peter the Great had invited him to Russia in 1725 to found an observatory in St. Petersburg, and his instruments were usually graduated to 2,400 or 2,700 divisions, a range suited to the severe local winters.
In 1738 Josias Weitbrecht, a colleague in St. Petersburg, recalibrated the instrument between two fixed points, 0 for boiling water and 150 for freezing. He sent such thermometers to scholars, among them Anders Celsius, whose own first scale was also inverted, running from 0 at boiling to 100 at freezing, before it was flipped after his death. Wikipedia says the Delisle thermometer stayed in use in Russia for almost a century, though that claim lacks a citation.
One degree Delisle is two thirds of a kelvin or Celsius degree. To convert, subtract two thirds of the Delisle reading from 100 to get Celsius, or from 373.15 to get kelvin. Boiling water is therefore 0 and freezing water is 150, so an ordinary winter day reads well above 100.
0 degrees Delisle = 373.15 kelvins (exactly).
Sources: Wikipedia: Delisle scale
Degree Fahrenheit (°F)
The temperature scale used in the United States and a few other countries: water freezes at 32 °F and boils at 212 °F. Proposed by Daniel Gabriel Fahrenheit in 1724.
Daniel Gabriel Fahrenheit, who lived from 1686 to 1736, proposed his scale in 1724. His zero came from a freezing mixture of ice, water and ammonium chloride (or sea salt), which holds a stable temperature, and his upper reference of about 96 was his estimate of human body temperature. His own letters say he built on Ole Rømer's scale. Accounts of how he picked zero differ, and a popular German story that it was the coldest winter day in his home city of Danzig has failed verification.
Around 1776 to 1777 a Royal Society committee led by Henry Cavendish fixed water's freezing point at 32 degrees and its boiling point at 212, exactly 180 degrees apart, which moved body temperature to about 98.6. Today the scale is defined through the kelvin; NIST puts absolute zero at minus 459.67 degrees Fahrenheit. It remains in everyday use in the United States and its territories, Palau, the Federated States of Micronesia, the Marshall Islands and the Cayman Islands. A comfortable room is around 70 degrees, which is about 21 degrees Celsius.
0 degrees Fahrenheit = 255.3722222 kelvins (approximately).
Sources: Wikipedia: Fahrenheit; NIST: the kelvin and the SI redefinition; NIST Guide to the SI, Appendix B.8: conversion factors
Related conversions
- Fahrenheit to Delisle (reverse)
- Delisle to kelvin
- Delisle to Celsius
- Kelvin to Fahrenheit
- Celsius to Fahrenheit
- Rankine to Fahrenheit
- Réaumur to Fahrenheit
- Newton to Fahrenheit
- Rømer to Fahrenheit
See all temperature units.