Key points are not available for this paper at this time.
THE chief difficulties in the benzidine method for determination of sulphate arise in obtaining the conditions requisite for maximum precipitation of benzidine sulphate. Most investigators have drawn attention to the importance of adjusting the acidity of the solution, while some of them have studied the inter- ference known to be caused by certain ions: chlorides, for example, may increase the solubility of benzidine sulphate Fiske, 1921; Kahn and Lieboff, 1928.
E. C. Owen (1936) studied this question.