Carl Sorenson wrote in USMA 24398:
>Where did Centigrade come from? Why was it changed to Celsius? I don't really have sources for this, but this is what I assume. Centigrade was defined in terms of the freezing and boiling points of water. Celsius is (at least currently) defined in terms of Kelvin (which uses the triple point). Thus, Celsius is tied to SI and centigrade is not, if this is correct. In practical terms the difference negligible, but Celsius is the term to use.
My understanding is that Celsius and centigrade are two names for the same thing, which has evolved over time. When I was a tourist in Germany in 1935 the temperature was in Celsius, while in France and English-speaking countries it was centigrade. This was somewhat confusing since some European surveying instruments (Wild of Heerbrugge) measured angles in centigrades.
"CIPM, 1948 and 9th CGPM, 1948:adoption of "degree Celsius"
"From three names (degree centigrade", "centesimal degree", "degree Celsius") proposed to denote the degree of temperature, the CIPM has chosen "degree Celsius" (PV, 21, 88).
"This name is also adopted by the 9th CGPM (CR,64)."
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