Scale of temperature the Swedish astronomer Anders Celsius (1701–1744), who developed a similar temperature scale two years before his death. The degree Celsius (°C) can refer to a specific temperature on the Celsius scale as well as a unit to indicate a temperature "interval "(a difference between two temperatures or an uncertainty). From 1744 until 1954, 0 °C was defined as the freezing point of water and 100 °C was defined as the boiling point of water, both at a pressure of one standard atmosphere. Although these defining correlations are commonly taught in schools today, by international agreement the unit "degree Celsius" and
Rømer scale temperature. He followed Ferdinand II of Tuscany's idea of enclosing a liquid in a sealed glass tube which made it immune to pressure changes. Rømer's thermometer was also an improvement in the fluid that he used. He used a mixture of alcohol and water, conveniently available in the form of wine. This avoided the drawbacks of both the low boiling point of pure alcohol and the extreme non-linearity of pure water near freezing. Daniel Gabriel Fahrenheit, inventor of the Fahrenheit scale, learned of Rømer's work and visited him in 1708. Fahrenheit described how he borrowed the idea for his scale