compare and evaluate spectra when the evaluation circuit 15 detects a spectrum in a specific program state it can influence the further program sequence if a reached residual dampness is detected by one of the receiving elements 12 13 and after detection by the evaluation circuit 15 the latter sends a corresponding signal to the control circuit 16 then the control circuit 16 continues the drying operation until the desired residual dampness set by the operator is reached it is similarly possible for the evaluation device 15 to trigger an alarm signal or end the respectively running program when a specific operating state is reached in this way it is possible to prevent textiles from being excessively treated or damaged this is of significance in particular if the operator has introduced textiles of different compositions into the drum 2 without noticing so that in this case the program can be discontinued in order that even the most sensitive of the textiles introduced is not damaged the receiving elements 12 13 either are individual diodes or are a combination of arrays including many diodes or phototransistors or similar receivers disposed ahead of the receiving elements 12 and 13 is a coupling in optical system the optical system can include a focusing lens a diffraction grating and or an optical waveguide electromagnetic beams from a flexible optical waveguide can also be sensed at the places that are unsuitable for attaching the receiving elements 12 13 the spectra of the textiles are either punctiform or the measuring signals.