= Bragg structure inference from measured intensities
{c}
<William Lawrence Bragg>'s 1913 structure paper connects a slit-selected beam, an oriented crystal and an <ionization chamber> to strength-versus-angle curves. Repeated <sine> ratios and matching <absorption coefficients> identify common radiation. Narrower slits resolve blended lines. Absolute <wavelengths> remain undetermined there; intercrystal comparisons first give relative scales. The <Bragg crystal reflection experiment of 1913> covers the alignment controls.<The Structure of Some Crystals as Indicated by their Diffraction of X-rays by William Lawrence Bragg>[pp. 268–272, especially Fig. 16: angular ionization scans, order/absorption comparison, slit resolution and wavelength-scale limitation]{ref}
<William Henry Bragg>'s 1915 Bakerian lecture, X-rays and Crystal Structure, separates the geometric and intensity arguments. Its Figure 9 compares reflection positions and strengths from three <sodium chloride> orientations; odd and even <diffraction orders> differ in strength along one orientation. The interpretation uses alternating scattering layers. Later, the <calcite> example identifies an internal <oxygen> coordinate that <symmetry> alone cannot fix. Improved <wave intensity> measurements revise a previously rough estimate. Thus a lattice assignment can precede determination of positions inside the <unit cell>; intensity interpretation also has experimental and theoretical limits. This is the father's 1915 lecture, distinct from the joint 1913 reflection paper.<Bakerian Lecture: X-rays and Crystal Structure by William Henry Bragg>[W. H. Bragg (1915), p. 253 authorship; pp. 260–261, Fig. 9 and alternating-layer argument; pp. 265–266, calcite coordinate and revised estimate]{ref}
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