The spin polarization of photoelectrons emitted by unpolarized cesium atoms exposed to circularly polarized light has been measured at wavelengths between 2300 and 3200 \AA{}. At certain wavelengths 100% polarization has been obtained. Slight deviations from theory have been observed. Irradiation of a broad mercury spectrum resulted in (81\ifmmode\pm\else\textpm\fi{} 3)% polarization with a current of 0.3\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}10}$ A.