Burg's maximum entropy spectral analysis is used in order to study monthly and annual mean values of absolute elements of the geomagnetic field at a number of world observatories. After removal of a parabolic trend, which accounts for most of the secular variation of internal origin, the residual variations clearly exhibit a worldwide character. A test study of monthly mean values at three sample observatories is first performed; earlier conclusions on both the origin and the geometry of the annual and semiannual variations are discussed. Annual mean values from approximately 30 observatories are next analyzed; most of the power found in the spectra, for periods between 2 and approximately 20 yr, is clearly related to the solar cycle (peaks around 10-12 yr and the first two harmonics). No peaks that can be related to phenomena of internal origin are found. The accuracy and resolving power of these data concerning the problem of the conductivity distribution in the deeper mantle are found to be rather disappointing.