Use of differential calorimeter for establishing temperature standards

Abstract

A differential calorimeter was used to set up and critically evaluate a series of organic substances as temperature standards over the range 50–330°. The conditions for acceptance of a standard substance were a sufficient degree of purity, thermal stability, absence of polymorphism, a suitable cryoscopic constant, low volatility and ready availability. Zone refining was mentioned as a method of purification to obtain the minimum degree of required purity at 99.9 mole per cent.