This report has two parts to it discussing mineralogical examination of pitchblende concentrates and nitric acid digest residues. Part I gives the results of a cursory examination with the petrographic microscope of samples of pitchblende concentrates and residues to see if there is a relationship between the mineral composition of the samples and the filterability of the residue. Part II gives a revaluation of the data in Report BMI-241 on the mineral composition of two residues from the nitric acid digestion of pitchblende concentrates at the Rallinckrodt Chemical Works.

From abstract: "The composition of vapors from aqueous nitric acid solutions boiling at 200 mm mercury total pressure is established for solutions containing between - and 67.5 w/o nitric acid. The volatility characteristics of low concentrations of chloride in the same concentration range of nitric acid have been measured in solutions boiling at 200 mm mercury. The effects of chloride concentration and pressure of boiling are evaluated. A spectrophotometric method of the determination of chloride in nitric acid solutions is described."