In the framework of the model of core-mantle (core consisting of astronomical silicate, mantle consisting of dirty ice) cylindrical grains partly oriented by the Davis-Greenstein mechanism, curves of the interstellar circular polarization q(/lambda/) are calculated. It is found that /lambda//sub c/, the wavelength at which the circular polarization changes sign, and the shape of the q(/lambda/) curves are determined primarily by the sizes of the dust grains. It is shown that Martin's dispersion relation gives the interstellar circular polarization with satisfactory accuracy only near the extrema of the curve q(/lambda/). The interstellar linear and circular polarizations of the star HD 204827 are interpreted in the framework of a two-cloud model.