4. Adiabatic method

The principle behind the method of measuring thermal capacities by adiabatic calorimetry, i.e. without heat exchange with the external environment, was described by M. Diot, [R 2 970] des Techniques de l'Ingénieur. This technique can be used relatively easily for a temperature range from ambient to 150°C. Above this temperature, the difficulties are considerable, and only equipment developed in research laboratories is used. As far as adiabatic methods are concerned, the difficulties arise from the fact that a calorimeter is never perfectly adiabatic, i.e....