The relative intensities of reflection of x-rays from the principal atomic planes of powdered sodium chloride

Measurements have been made on the relative intensities of reflection of the alpha doublet of characteristic molybdenum x-rays, from powdered sodium chloride, using the modified Bragg apparatus described in a previous communication. Determinations were made with (a) filtered rays and (b) rays reflected from a calcite crystal. In a separate investigation the lines were obtained on photographic plates and their intensities were found photometrically. All three series gave results that are in agreement with the measurements of Bragg, James and Bosanquet on large crystals, after their results are corrected for their determinations of the "extinction" in those crystals. Our experiments thus indicate that results on measurements with 325 mesh powder are as free from the effects of "extinction" as are the results of the workers just mentioned.