Srikantan and Krishnan (this Journal, 1949, 28, 415) have used the chromatophic method of estimating copper in brass and bronze, and to measure the concentration from the dimensions of chromatograms have adopted Freundlich's adsorption isotherm. The data in the previous paper (ioc.cit.) illustrate for copper cation from M/25 to M/200 strengths of nitrate solutions. The length of the chromatogram being directly propor­tionate to concentration,- h/c was constant giving a value of 181(av.) with I c.c. of the copper nitrate solution in each case and the diameter of the tube being 0.7 cm. and for the same composition but different diamater of tube in the same quantity of solution eh was constant.