ABSTRACT New photoelectric surface brightness measurements of the Merope reflection nebula in 14 positions are reported. A KPNO 0.9-m telescope was used in combination with uvby filters and the positions of the measured fields are nearly identical to those observed by the Astronomical Netherlands Satellite at 3300 A, 2500 A, 2200 A, 1800 A, and 1550 A. The change of the surface brightness distribution with wavelength south of and immediately surrounding 23 Tau has been analyzed with the aid of suitable multiple scattering models. Three different aspects of the observational data can be understood in a consistent manner, if the scattering phase function is changing from a strongly forward throwing shape in the visible (g 0.7) to a more isotropic form in the spectral region near 1500 A, (g 0.25). This supports earlier conclusions that the far ultraviolet scattering and the steep increase in interstellar extinction in the far ultraviolet are caused primarily by very small (10-6 cm or less) grains with an isotropic scattering phase function. Key words: reflection nebula-grain scattering properties