William John Macquorn Rankine proposed the after himself named temperature scale in 1859. As with Lord Kelvin 11 years before, he set the zero-point of his scale from smallest possible temperature. This temperature is given, if the particles of an object are not moving. The distance between the degrees he used the same as the Fahrenheit-scale. This results in the following conversions:
[°R] = [°F] + 459,67
[°F] = [°R] - 459,67
Today the unit Rankine ist used mostly in countries that also use the Fahrenheit-scale, as in the United States. It isn't a unit of the international system of units.
Rankine was born on the 5th of July 1820 in Edinburgh, Scotland. An the university of Edinburgh he studied natural science between 1836 to 1838, but left without a degree, to work as an assistant of the building engineer John Benjamin MacNeill. In this time he started to publish scientific works.
Today he is considered like Kelvin to be one of the founders of classical thermodynamics. Besides this scientific field of work he also contemplated technical engineering problems. So he developed a method to estimate the stability from metal frame constructions and examined the problem of metal fatigue, for an example. This questioning was very interesting in the young railway industry.
William John Macquorn Rankine died at the age of 52 on the 24th of December 1872 in Glasgow.