Polarization effects involving our Galaxy have been studied in two ways: firstly, by observations of the polarization of the galactic radiation itself, and secondly, by the effects of galactic magnetic fields and ionization on the polarization of extragalactic radio sources. For an aerial of fixed dimensions, the intensity of the background varies at about λ2·5 (λ is wavelength) and that of the sources at about λ0·7. Thus background measurements are restricted to the longer wavelengths where the radiation is sufficiently intense, while sources are most easily studied at the shorter wavelengths where background confusion is small. The background radiation includes a component from small unresolved extragalactic radio sources in addition to the galactic radiation which is of interest in the first type of measurement. Both types of observation have been made with the 210-foot aerial at Parkes; the observations of sources were done in collaboration with J. B. Whiteoak and that of the galactic radiation with J. A. Roberts, assisted by J. B. Whiteoak and A. G. Little for part of the time.