Olof Celsius Olof Celsius was made a member of the Royal Swedish Academy of Sciences in 1739. Olof Celsius Olof Celsius (the elder) (19 July 1670 – 24 June 1756) was a Swedish botanist, philologist and clergyman, He was a professor at Uppsala University, Sweden. Celsius was a mentor of the botanist and scientist Carl Linnaeus. Celsius wrote his most famous book on biblical plants, "Hierobotanicon", in 1745-47. Olof Celsius's nephew Anders Celsius was an astronomer who invented a temperature scale where 100 represented the freezing point of water and 0 represented the boiling point. Jean-Pierre Christin, in 1744 reversed the scale
International Temperature Scale of 1990 measure the very same temperature with ease due to the advantages of a comprehensive international calibration standard featuring many conveniently spaced, reproducible, defining points spanning a wide range of temperatures. Although “International Temperature Scale of 1990” has the word “scale” in its title, this is a misnomer that can be misleading. ITS–90 is not a scale; it is an "equipment calibration standard". Temperatures measured with equipment calibrated per ITS–90 may be expressed using any temperature scale such as Celsius, Kelvin, Fahrenheit, or Rankine. For example, a temperature can be measured using equipment calibrated to the kelvin-based ITS–90 standard, and that