AUTOMATIC ADIABATIC SOLUTION CALORIMETER USING THERMISTORS

A calorimeter is described, of capacity 40–50 ml, which is suitable for the investigation of solutions between 0 °C and 70 °C. Temperatures are measured to better than 0.0001 °C using thermistors and the latter are also used to provide automatic adiabatic control. A novel mechanism is used for opening sample cells and the associated heat effect can be measured with a precision of 0.01 cal or better. Stirring of the calorimeter is achieved by continuous rocking of the vessel through 180°. The performance of the calorimeter is illustrated by results obtained for the heat of solution of NaCl at 25 °C.