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Hercules X-1 has been observed by the LAC instrument on board the Ginga satellite during August 1988 when pre-eclipse dips of Her X-1 were taking place. An analysis of the X-ray spectra obtained by the LAC is presented here. Large changes in spectral shape are seen as a given dip progresses in time. A spectral model is applied which includes a scattered and an absorbed component as well as fluorescent iron line emission. From the changes in spectral parameters, evidence is found for some properties that have not been previously detected in X-ray binaries: the power law index of the X-ray spectrum increases with luminosity; the covering fraction of a scattering corona by the accretion disk is variable on several minute timescales; and the fluorescent iron line energy is downshifted by Compton scattering.
