Rankine

Rankine is a temperature scale that, like kelvin, sets zero at absolute zero, but uses Fahrenheit degrees. It is named after Scottish engineer and physicist William John Macquorn Rankine, who proposed it in 1859. See Rankine-Hugoniot equation.

A difference of 1 degree R. is equal to a difference of 1 degree F, but absolute zero is 0 degrees R, or -459.67 degrees F. Thus:

• To convert from Fahrenheit to Rankine, add 459.67.
• To convert from Rankine to Fahrenheit, subtract 459.67.
• To convert from kelvin to Rankine, multiply by 1.8.
• To convert from Rankine to kelvin, divide by 1.8.

Other temperature scales include Fahrenheit (1724), Réaumur (1730), Celsius (1742), and Kelvin (1862).