Definition:Celsius/Historical Note

Historical Note on Celsius
The Celsius scale is based on that proposed in $1742$ by the astronomer.

He defined the upper and lower reference points from the melting and boiling points of water. These were initially the other way round from their current definitions: $0 \,^\circ \mathrm C$ was for the boiling point and $100 \,^\circ \mathrm C$ was for the melting point.

originally called it the centigrade scale, but for various reasons the name was a source of confusion, and so in $1948$ the name Celsius was adopted.

This is the system of measurement of temperature that is generally taught in schools.