# Delisle to Réaumur (°De to °Ré)

Source: https://www.unitconvertercalculator.com/temperature/delisle-to-reaumur/

To convert Delisle to Reaumur, use the formula: Re = 80 - De x 8/15. The Delisle scale runs backwards compared to most temperature scales, with higher numbers indicating colder temperatures. 0 Delisle (boiling) = 80 degrees Reaumur, 150 Delisle (freezing) = 0 degrees Reaumur.

## Formula

°De via Kelvin to °Ré

## Conversion Table

| Delisle (°De) | Réaumur (°Ré) |
|---|---|
| 0 °De | 80 °Ré |
| 50 °De | 53.333333333336 °Ré |
| 100 °De | 26.666666666664 °Ré |
| 150 °De | 0 °Ré |
| 200 °De | -26.666666666664 °Ré |
| 250 °De | -53.333333333336 °Ré |
| 300 °De | -80 °Ré |
| 350 °De | -106.66666666666 °Ré |
| 400 °De | -133.33333333334 °Ré |
| 500 °De | -186.66666666667 °Ré |
| 559 °De | -218.13333333333 °Ré |

## Units

### Delisle (°De)

A historical inverted temperature scale invented by Joseph-Nicolas Delisle in 1732. Water boils at 0 °De and freezes at 150 °De. Higher numbers mean colder temperatures.

### Réaumur (°Ré)

A historical temperature scale where water freezes at 0 °Ré and boils at 80 °Ré. Named after René Antoine Ferchault de Réaumur. Once widely used in Europe.

## Background

This conversion bridges the 18th-century Russian-adopted Delisle scale with the Reaumur scale. Historical Russian temperature records from the era of Catherine the Great and earlier require this conversion for comparison with modern scientific data expressed in Reaumur units.

## Good to Know

The Delisle and Reaumur scales represent two French contributions to thermometry that both lost to the Swedish Celsius scale. France, despite producing both scales and later the metric system, ended up adopting a temperature scale invented by a Swede. This is one of science's gentle ironies: the nation that rationalized all other measurement could not produce the winning temperature scale.

## FAQ

### How do you convert Delisle to Reaumur?

Use the formula Re = 80 - De x 8/15. 0 Delisle (boiling) = 80 degrees Reaumur, 150 Delisle (freezing) = 0 degrees Reaumur.

### Why does the Delisle scale run backwards?

Delisle measured how far below the boiling point a temperature was. Higher numbers meant further from boiling, which means colder. This inverted logic was logical for his laboratory work but confusing for everyday use.

### When would you need to convert Delisle to Reaumur?

When interpreting historical Russian scientific records from the 18th-19th centuries and converting them to Reaumur for modern analysis or comparison.

## Non-Frequently Asked Questions

### Were Delisle and Reaumur rivals?

Rene Antoine Ferchault de Reaumur published his scale in 1730, just two years before Delisle published his in 1732. Both were French scientists working on thermometry at the same time. Reaumur's scale gained wider adoption in continental Europe, while Delisle's found its niche in Russia. They were contemporaries who solved the same problem differently.

### Is it a coincidence that both scales were created by Frenchmen?

Not entirely. France in the early 18th century was the center of European scientific activity. The French Academy of Sciences funded thermometric research, attracting Reaumur and sending Delisle to Russia. Both scales emerged from the same intellectual environment - the French Enlightenment's obsession with rational measurement that would later produce the metric system itself.

### Which scale had the better run: Delisle or Reaumur?

Reaumur had the longer and broader run. It was standard in France, Germany, and parts of Europe for over a century, and it still appears occasionally in European cheese and confectionery traditions. Delisle was confined mainly to Russia. But both were eventually eclipsed by Celsius, which combined the simplicity of Reaumur (0-100 range for water) with wider international adoption.

## Related Articles

- [Why We Measure: The Deepest Urge in Human Civilisation](https://www.unitconvertercalculator.com/blog/why-we-measure)
- [The Map Is Not the Territory: Why Every Measurement Is Wrong](https://www.unitconvertercalculator.com/blog/the-map-is-not-the-territory)
- [Zero: The Most Dangerous Number in Measurement](https://www.unitconvertercalculator.com/blog/zero-the-most-dangerous-number-in-measurement)
- [The Speed of Everything: How We Measure From Glaciers to Light](https://www.unitconvertercalculator.com/blog/the-speed-of-everything)
- [Why Your Recipe Is Lying to You: The Chaos of Cooking Measurements](https://www.unitconvertercalculator.com/blog/why-recipe-measurements-are-unreliable)
- [When Measurements Go Wrong - Disasters, Blunders and Happy Accidents](https://www.unitconvertercalculator.com/blog/when-measurements-go-wrong)
- [The Surprising Stories Behind Everyday Units of Measurement](https://www.unitconvertercalculator.com/blog/stories-behind-measurement-units)
- [Metric vs. Imperial - The Complete Guide to the World's Two Measurement Systems](https://www.unitconvertercalculator.com/blog/metric-vs-imperial-complete-guide)
- [Temperature Conversion Guide for Travel, Cooking & Weather](https://www.unitconvertercalculator.com/blog/temperature-conversion-guide)

## See Also

- [Réaumur to Delisle](https://www.unitconvertercalculator.com/temperature/reaumur-to-delisle/)