In order to show if the relationshop obtained for Si 2516 between the slope of the calibration curve and its concentration has more general significance we carried out experiments on 13 spectral lines of two nultiplets belonging to the cobalt and nickel spectra. Results show that for a particular spectral line the slope depends on concentration and fur a definite range of the concentration, slope of the curves of spectral lines of the same mnltiplet varies linearly with log of the natural intensity of the corresponding lines. Thus, we may say that in spectrochemical analysis, slope b of the calibration curve essentially depends on the intensity of the spectral line and this in turn depends on the concentration of the constituent and the natural intensity of the line concerned. We believe that an understanding of the physical significance of b is helpful in actual analysis as to find the condition which gives a better slope of the working curve.