IN THE first paper 1 a method of size-frequency analysis was presented and it was remarked that in the analytical study of a series of dispersed particle systems, simple graphical methods may be highly efficient and all that is necessary, for certain purposes. This was well illustrated by data from a group of silver bromide precipitates in gelatin obtained by Dr. R. H. Lambert of these laboratories.
Detailed description of the methods used in their preparation will be furnished in another paper from this laboratory. For our purpose, i.e., to show that these particular graphical methods are especially capable of simplifying the apparent size-frequency distribution, disclosing any regularities and indicating their nature, it is sufficient to state that thirty-three precipitates were obtained which varied from each other only in two carefully controlled factors so that four separate series could be formed which varied in themselves only in one factor. Size-frequency determinations were then made in the usual manner, ~ using, in each case, the same concentrations of silver bromide per unit area of single layer plate. The number of grains measured averaged 372o per final curve, which in each case was a mean of three separate determinations. DOUBLE LOG ANALYSIS OF PRECIPITATION DATA.
When one such series was plotted on double log paper the graphs so resembled parabolas that this curve was applied to them using a string and triangle. This rather crude method fitted them surprisingly well, although the extreme tails were not plotted, which later proved significant. It was found that by * Communication No. 300 from the Research Laboratory of the Eastnaan Kodak Company. ~LovELANI) and TRIVELLI. JOUR. FRANK. INST., ,Part I, Aug., 1927.