The rms spectra from these subsets, shown in the bottom two panels of Fig. 5, show the same 686 profile characteristics seen in the set B Subset 1 data shown in the second panel.

Discussion
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The Continuum
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As described in the previous section, the X-ray and optical continuum variations are not closely coupled on short time scales. The X-ray continuum shows large scale variations on short time scales, as is typical of the NLS1 class. The rapid variations seen in the X-ray are not detected in the optical, as has previously been reported by Done et al. (1990) for this same source and by Young et al. (1999) for IRAS 13224$-$3809. However, if we average over the short time-scale flares, then the X-ray and optical continuum variations [*do*]{} seem to be coupled, though the time resolution of this experiment is insufficient to determine whether there is any lag between them at the level of days or less. The absence of strong coupling of the hard X-ray and optical continuum variations argues against reprocessing models in which hard X-rays are absorbed by a dense plasma (such as the accretion disk) and the energy is re-radiated at longer wavelengths (Guilbert 