Newton to Reaumur
N
°Ré
Conversion History
| Conversion | Reuse | Delete |
|---|---|---|
1 N (Newton) → 2.42424242424242424 °Ré (Reaumur) Just now |
Quick Reference Table (Newton to Reaumur)
| Newton (N) | Reaumur (°Ré) |
|---|---|
| 0 | 0 |
| 6.6 | 15.999999999999999984 |
| 12.2 | 29.575757575757575728 |
| 22 | 53.33333333333333328 |
| 33 | 79.99999999999999992 |
About Newton (N)
The Newton scale is an obsolete historical temperature scale proposed by Isaac Newton around 1701, predating both Celsius and Fahrenheit. It sets 0°N at the freezing point of water and 33°N at the boiling point — a 33-degree span. Newton chose 33 because it divides cleanly into thirds and twelfths, reflecting duodecimal arithmetic conventions of the time. Body temperature is approximately 12.2°N. Newton calibrated his scale using linseed oil as the thermometric fluid. His scale influenced later thermometrists but was never widely adopted and is today of primarily historical and educational interest, appearing in scientific history discussions and temperature conversion tools.
Body temperature (37°C) is approximately 12.2°N on Newton's scale. A warm summer day of 25°C equals about 8.25°N.
Etymology: Proposed by Isaac Newton (1643–1727) in his 1701 paper "Scala Graduum Caloris" (Scale of the Degrees of Heat), published anonymously in Philosophical Transactions. Newton used a linseed oil thermometer and calibrated it against the freezing point of water and body temperature, later extending it to a second reference at the boiling point.
About Reaumur (°Ré)
The Réaumur scale (°Ré) is a historical temperature scale proposed by French scientist René Antoine Ferchault de Réaumur in 1730. It sets 0°Ré at the freezing point of water and 80°Ré at the boiling point. Réaumur divided the interval into 80 parts because he calibrated it using a dilute alcohol thermometer whose fluid expanded by 80 parts in volume between these two reference points. The scale was widely used in France, Germany, and Russia throughout the 18th and early 19th centuries before being replaced by Celsius. A vestigial use survives in confectionery, where some older European recipes specify sugar syrup temperatures in Réaumur degrees.
Body temperature (37°C) is approximately 29.6°Ré. A comfortable room at 20°C is 16°Ré. Boiling water is 80°Ré.
Etymology: Named after René Antoine Ferchault de Réaumur (1683–1757), a French polymath best known for his multi-volume work on insect natural history. He developed the scale in 1730 using dilute alcohol (roughly 80% water, 20% alcohol) whose measured volumetric expansion between freezing and boiling defined the 80-degree interval.
Newton – Frequently Asked Questions
Who invented the Newton temperature scale?
Isaac Newton proposed the scale in 1701 in his paper "Scala Graduum Caloris", published anonymously in Philosophical Transactions of the Royal Society. He used a linseed oil thermometer and calibrated it against the freezing point of water and body temperature as fixed reference points.
What are the reference points of the Newton scale?
0°N is the freezing point of water and 33°N is the boiling point of water, giving a 33-degree range. Newton also used body temperature (approximately 12°N) and "the greatest summer heat" as intermediate calibration points. These are the same two endpoints used by later scales, just with different degree spans.
Why did Newton choose 33 degrees for boiling water?
Newton chose 33 because it factors neatly: 33 = 3 × 11, and one-third of 33 (11°N) corresponds approximately to body temperature in his calibration. The choice reflects his preference for divisions into thirds and twelfths, common in pre-metric scientific notation, rather than the decimal basis used by Celsius.
How does the Newton scale compare to Celsius?
Newton and Celsius share the same zero (freezing water = 0), but Newton's boiling point is 33°N versus 100°C. To convert: °N = °C × 33/100 (or × 0.33). Room temperature (20°C) is 6.6°N; body temperature (37°C) is 12.21°N.
Is the Newton temperature scale still used today?
No. The Newton scale was never widely adopted and fell out of use by the mid-18th century as Fahrenheit and Celsius became dominant. It survives today only in historical accounts of thermometry and in temperature conversion tools as an educational curiosity about the origins of quantitative temperature measurement.
Reaumur – Frequently Asked Questions
Who invented the Réaumur scale?
The Réaumur scale was proposed by René Antoine Ferchault de Réaumur in 1730. Réaumur was a French scientist primarily known for his contributions to natural history, particularly entomology. His thermometer used dilute alcohol and was calibrated between the freezing and boiling points of water, with the scale divided according to the actual expansion of the alcohol.
Why does the Réaumur scale go from 0 to 80?
Réaumur calibrated his scale based on the physical expansion of his thermometric fluid — a specific dilute alcohol mixture. Between water's freezing and boiling points, the fluid expanded by exactly 80 parts in 1000 of its volume at freezing. He used this empirical measurement directly as the degree count, making 80°Ré the boiling point. The number 80 was not chosen arbitrarily but measured.
Why did France abandon Réaumur in favor of Celsius?
The French Revolution's embrace of the metric system in the 1790s demanded decimal-friendly units. Celsius's 0-to-100 scale fit the decimal philosophy perfectly; Réaumur's 0-to-80 did not. The French Academy of Sciences standardized Celsius for scientific work, and it spread through Napoleonic Europe. Réaumur lingered in German-speaking regions and Russia into the mid-19th century but eventually yielded everywhere. The irony is that Réaumur was French — his own country was the first to abandon his scale.
How do you convert Réaumur to Celsius?
Multiply the Réaumur value by 5/4 (or 1.25). For example, 16°Ré × 1.25 = 20°C. To convert Celsius to Réaumur, multiply by 4/5 (or 0.8). The two scales share the same zero (0°C = 0°Ré); they differ only in degree size, since 100°C = 80°Ré.
How did sugar confectioners use Réaumur degrees in candy-making?
Classic French confectionery texts list sugar syrup stages in Réaumur: "thread" stage at 80°Ré (100°C), "soft ball" at 94°Ré (117°C), "hard crack" at 124°Ré (155°C). Pastry chefs memorized these benchmarks and tested with a thermometer or by dripping syrup into cold water. Some vintage French and Swiss recipe books still reference Réaumur temperatures — modern reprints add Celsius equivalents in brackets. It is the last practical domain where Réaumur had a lingering foothold.