THE abandonment of the 1939 British Association meeting at Dundee involved, among other things, the cancellation of what promised to be a discussion of great interest on the temperatures of stellar surfaces. Fortunately, however, Prof. W. ?. ?. Greaves's opening address on the subject appears in the October number of the Observatorymagazine (62, 252; 1939). In his review of the present position, Prof. Greaves directs attention to the way in which recent observations-notably the colour temperature measurements carried out during the last ten years in England, Germany and France-have forced astrophysicists to the conclusion that no unique meaning can now be attached to the phrase ‘the temperature of a star’, because a stellar surface does not radiate even approximately as a black body.