The Utrecht Orbiting Ultraviolet Stellar Spectrophotometer S59 on board the ESRO TD-1A satellite has observed ultraviolet spectra of about 200 stars in the wavelength regions 2060–2160 Å. 2490–2590 Å and 2770–2870 Å with a resolution of 1.8 Å (cf. de Jager et al., 1974). The spectra are analyzed in order to find UV criteria for stellar classification. Particular attention has been given to Fe III lines since no strong lines of this ion occur in the visible part of the spectrum. As one of the most striking results, it is found that the feature at 2078 Å, which is mainly due to Fe III, is very sensitive to luminosity.