Réaumur

The Réaumur scale is a temperature scale named after French physicist René Antoine Ferchault de Réaumur, who developed it in 1730. It was designed to be a practical temperature scale based on the properties of water, with water freezing at 0°Ré and boiling at 80°Ré at standard atmospheric pressure.

The Réaumur scale uses 80 degrees between the freezing and boiling points of water, which Réaumur chose because it could be easily divided into halves, quarters, and eighths. This made it convenient for practical measurements and calculations in the 18th century.

The scale was widely used in Europe, particularly in France, Germany, and Russia, during the 18th and 19th centuries. It was popular in scientific and industrial applications before being largely replaced by the Celsius scale in the 20th century.

Historically, Réaumur was used in European countries for weather reporting, scientific research, and industrial applications. It was particularly popular in France and was used in many scientific publications and industrial processes.

Today, Réaumur is rarely used except in some specialized applications, such as certain cheese-making processes in Switzerland and some traditional European recipes. It is mainly of historical interest and is occasionally referenced in historical documents.

In historical scientific work, Réaumur was used for temperature measurements in chemistry, physics, and biology. Many important scientific discoveries and measurements from the 18th and 19th centuries were recorded using the Réaumur scale.

The Réaumur scale influenced the development of other temperature scales and contributed to the standardization of temperature measurement. Its 80-degree range between freezing and boiling points was a practical choice for many scientific applications.

The Réaumur scale is defined by the relationship °Ré = °C × 4/5, where the freezing point of water is 0°Ré and the boiling point is 80°Ré. This makes it easy to convert between Réaumur and Celsius.

While Réaumur is no longer officially recognized in most countries, it remains part of the historical development of temperature measurement. The scale's influence can be seen in the development of more modern temperature scales and measurement techniques.