I promised you a photo of this vintage piece a few weeks ago. How time flies.
I found this unique old thermometer in an antique shop in Sweden when I was on holiday there a few weeks ago. Interestingly it´s both in the Celcius- and the Rankine scale. At least I think it´s the Rankine - it could also be the Römer- or Réaumur scale.
Rankine is a thermodynamic temperature scale named after the Glasgow University engineer and physicist William John Macquorn Rankine, who proposed it in 1859.
The symbol for degrees Rankine is °R. Zero on both the Kelvin and Rankine scales is absolute zero, but the Rankine degree is defined as equal to one degree Fahrenheit, rather than the one degree Celsius used by the Kelvin scale. A temperature of −459.67 °F is exactly equal to 0 °R.
Rankine source: Wikipedia