Callendar's equation

Callendar's equation

[′kal·ən·dərz i′kwā·zhən]
(thermodynamics)
An equation of state for steam whose temperature is well above the boiling point at the existing pressure, but is less than the critical temperature: (V-b) = (RT/p) - (a/Tn), where V is the volume, R is the gas constant, T is the temperature, p is the pressure, n equals 10/3, and a and b are constants.
A very accurate equation relating temperature and resistance of platinum, according to which the temperature is the sum of a linear function of the resistance of platinum and a small correction term, which is a quadratic function of temperature.