Distribution of Particle Size in Dust

Abstract

DR. DAVIES¹ refers to the significance of the multiplier K in the ‘power law’ frequency function dN = KD^−γ dD describing the size distribution of particles. His remarks, however, could apply to any function of the general form Kƒ(D). The multiplier K does not in any way define the relative frequencies with variation of D ; this is completely defined by ƒ(D). If, however, two or more distributions were combined, it would be necessary to specify individual values of K in order to define the contributions of the different components: Apart from its use with a multi-term distribution the multiplier K could be used to adjust the value of a definite integral to a specific total, although it is rarely used for this purpose. In the examples shown by Davies the total is fixed at 100 per cent and the lower limit of the integral is indirectly varied by varying K. His curves express the cumulative per cent below size where 100 per cent corresponds to: