Usually we use ‘Celcius’ or ‘Fahrenheit’ as our guide to scale the temperature. Look what we found here: They use ‘Celcius’ and ‘Rheamur’(?).

 

photo by edwin 

Look at the picture: at the left side we have ‘C’ as ‘Celcius’. Then look at the right side of the picture: ‘RH’ as ‘Rheamur’…???