1. von Weimarn, P. P., Canad. Chem. and Met., 10, 227 (1926).
2. For a review, see von Weimarn, in Alexander's “Colloid Chemistry”, 363 (Chem. Catalog Co., Inc., 1932).
3. Harris, M., and Johnson, T. B., Indust. Eng. Chem., 22, 965 (1930).
4. Meunier, L., and Ray, G., C.R. Acad. Sci., Paris, 184, 285 (1927).
5. Harris, M., J. Res. Nat. Bur. Stand., 13, 151 (1934).