Kelvin

The Kelvin scale is a thermodynamic (absolute) temperature scale referenced to absolute zero. The kelvin is a unit of measurement for temperature. Both are named after the Belfast-born engineer and physicist William Thomson, 1st Baron Kelvin (1824-1907), who in 1848 whote of the need for an "absolute thermometric scale". The freezing point of water is set at 273.15K and the boiling point at 373.1339K.

Rankine

The Rankine scale is a thermodynamic (absolute) scale named after the Scottish engineer and physicist William John Macquom Rankine (1820-1872), who proposed it in 1859. The freezing point of water is set at 491.67°R and the boiling point at 671.64102°R.