With modern experimental technique, it is possible to measure a peak shape with sufficient accuracy to justify an interpretation based on the precise shape of the reflection. The corrected shape is represented by a cosine Fourier series and a set ofAncoefficients determined. A plot of theAncoefficientsvs. nwill distinguish between distortion and particle size broadening. From theAncoefficients, root mean square values of strain averaged over lengthsna3are obtained. The decrease in these values for increasing lengthna3is a direct indication of the non‐uniform nature of the strains in cold‐worked metal. By measuring several orders of a given plane, it is theoretically possible to obtain a distribution function of the strains directly from a Fourier transform of theAncoefficients.