The calibration coefficients K were determined by using nine pure compounds in the molecular weight range of 178 to 716 in benzene

chloroform and methyl ethyl ketone at several temperatures in two apparatus of different thermistor assembly. K was found to be constant in the molecular weight range of solute studied. In order to investage the effect of structure of instrument on the results of measurement

several polymers of different molecular weights ranging from 1200 to 3.5×104 were measured. Approximatly the same results were obtained. It has also been found that the time required to reach the steady state is qpparently depend upon the na-ture of solvents.