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
John Jones (astronomer) John Jones (astronomer) John Jones (18181898), also known as Ioan Bryngwyn Bach and Y Seryddwr ("The Astronomer"), was a Welsh amateur astronomer. He was born at Bryngwyn Bach, Dwyran, Anglesey, and received only an elementary education. From the age of twelve, he worked as a farm labourer. He later worked as a counter of cargoes of slate as they were loaded on to ships in Bangor, in modern Gwynedd. Unusually for someone of his background, he was not only a musician and a poet but proficient in several languages. He is noted mainly for his interest in astronomy: he constructed