19 May - Jean-Pierre Christin developed centigrade temperature scale

 

On 19 May 1743, Jean-Pierre Christin developed the centigrade temperature scale.

*Jean-Pierre Christin,* was a French physicist, mathematician, astronomer and musician. His proposal in 1743 to reverse the Celsius thermometer scale (from water boiling at 0 degrees and ice melting at 100 degrees, to where zero represented the freezing point of water and 100 represented the boiling point of water) was widely accepted and is still in use today.

His *thermometer* was known in France before the Revolution as the thermometer of Lyon. One of these thermometers was kept at the Science Museum in London.

*Celsius*

The Celsius scale, also known as the centigrade scale, is a temperature scale used by the International System of Units (SI). As an SI derived unit, it is used by all countries except the United States, the Bahamas, Belize, the Cayman Islands and Liberia. It is named after the Swedish astronomer *Anders Celsius,* who developed a similar temperature scale. The degree Celsius (symbol: °C) can refer to a specific temperature on the Celsius scale or a unit to indicate a difference between two temperatures or an uncertainty. Before being renamed to honor Anders Celsius in 1948, the unit was called centigrade, from the Latin centum, which means 100, and gradus, which means steps.