“…This procedure was first employed by Becker (2) and later improved by Rossmann (35). Modifications have been suggested by Sabalitschka and Dietrich (36), Toms (39), Boeseken and Pols (4), Brocklesby and Harding (6), and others, but have not found extensive use. The bromine absorption is determined gravimetrically and, because of the small sample weights used, a microbalance is required.…”