Saraiva et al. (1993) reported cloud-point curves for the system poly(ethylene glycol)/water using a thermo-optical analysis apparatus identical to that used by Bae et al. (1991). Even though both groups used nearly the same chemicals, a slight discrepancy was found between the data by Bae et al. and those by Saraiva et al. This discrepancy is, in part, due to a temperature calibration method that neglects temperature gradients in the heating chamber. An improved calibration method and an easy way to minimize temperature gradients is presented here.