Baade-Wesselink Radii of Long-Period Cepheids - New Observations

The radii of Galactic Cepheids as determined from a version of the Baade-Wesselink technique are shown to depend upon the colour index used to define the temperature scale. The (V-I) radii are systematically larger than the commonly used (B-V) radii and are probably better estimators of the true radii. There still remains a problem, however, in reconciling the period-radius relation with the period-luminosity-colour relation.