A polydisperse sample can be statistically represented by a log-normal distribution having two parameters, viz., geometrical standard deviation sigma(g) and modal size parameter X(m). In an earlier paper a method to determine sigma(g) from the shift in the angular position of the maximum in Itheta(2) vs theta plot was discussed. The present paper describes a method of determining the other parameter X(m) from the polarization measurement in the forward direction. This can be achieved by comparing the angular position of maxima in P (degree of polarization) vs theta with that of the similar curve of a single particle. Certain experimental results are also discussed. This method is expected to be useful in routine particle size analysis.