The temperature changes caused by adiabatic pressure changes were studied in a polymersolvent system at high pressures. It is shown that the temperature determination by means of light scattering measurements is in good agreement with thermodynamic calculations of the temperature change for adiabatic pressure changes. The directly measured temperature changes by use of a thermocouple are found to be far too small. New York 1970 P. Debye, H. Coll, D. Woermann, J. Chem. Phys. 32, 939 ( I W )