Ores. Progress reports, Metallurgical Division: 15, Ore-dressing studies, Use of wetting agents in flotation, by R. S. Dean, J. Bruce Clemmer, and S. R. B. Cooke; Flotation of complex molybdenum-vanadium ores from Mammoth, Ariz., by J. Bruce Clemmer and S. R. B. Cooke; Short-column hydraulic elutriator for subsieve sizes, by S. R. B. Cooke.