Réaumur to Celsius

Réaumur (°Ré): The Réaumur scale has the freezing point of water at 0 °Ré and the boiling point at 80 °Ré. It was popular in parts of Europe in the 18th and 19th centuries, particularly in France and Germany.

Celsius (°C): The Celsius scale, also known as the centigrade scale, is the most widely used temperature scale in the world. It is an interval system defined by 0 °C as the freezing point of water and 100 °C as the boiling point of water at standard atmospheric pressure.