Figure 9: Comparison of nine X-ray datasets as described in the text. Each dataset has been normalised or renormalised according to scheme III in order that they can be put on the same graph. Where original data were not supplied or not available in numerical form, the values have been digitized from published graphs. The error introduced in doing so is no larger than the thickness of the lines or points used, but not every published point would necessarily be sampled, so the curves in those cases should be regarded as representative of the published data rather than the actual data themselves.