THE recent experimental proof1 that the sun emits energy on radio frequencies was followed by evidence2 that the amount of such energy can increase markedly during the passage of important sunspots across the solar disk. Such sunspots are invariably associated with strong magnetic fields, the influence of which almost certainly extends into the upper chromosphere and inner corona. Considerations of optical depth indicate that the observed emissions cannot come from below these levels, so that they must arise in regions where the electron collision frequency is much less than the (radio) wave-frequency, and where the latter is probably of the same order of magnitude as the gyromagnetic frequency He/ m. Under these conditions we should expect to find evidence of the magnetic field in the production of gyratory effects at the source of the emissions, and/or in differential absorption of right-handed and left-handed components of polarization during transmission through the corona.