ANALYTICAL EDITION 305 2. Separations are unnecessary, as hexavalent chromium is reduced by boiling with hydrochloric acid, and the iron may then be determined by direct reduction with standard titanous chloride solution, and ammonium thiocyanate as indicator.If desired, iron may first be separated from hexavalent chromium by 'precipitation with ammonia and then determined with titanous chloride.3. Fifty-seven determinations of nine different leathers, both chromeand vegetable-tanned, show that the new method is accurate within ±0.01 per cent of the Fe2Os present in the case of chrome-tanned leathers, and within ±10 per cent of the iron present in vegetable-tanned leathers for 0.01 to 0.03 per cent total Fe2Os content.4. Hazardous reactions following the new method were not encountered and the speed of analysis by comparison with existing methods is improved without sacrificing accuracy.