POWDER DISPERSIBILITV The ratio Smo/Sx2 of the powder surface measured by the BET method has a strong correlation to wettability of powder with water, but its correlation to dispersibility of powder is not so strong. In dispersing powder in water, whether, in the first place, the surface of powder easily wets with water and disperses well in water depends on the hydrophilicity of the powder surface. But after the powder is once forced to disperse by application of mechanical force, the degree of dis- persibility depends on its t-potential, specific gravity, and other factors, rather than on its hydrophilicity. Since, however, the ratio Sn2O/SN• measured by the BET method indicates in an extremely direct manner the hydrophilicity and hydrophobicity of powder surface, it may be used in the cosmetics industry as an important characteristic value of powder. ACKNOWLEDGMENT The authors wish to express their sincere thanks to Yooichi Miya, Director, Shiseido Chemical Research Laboratory, for his advice on pre- paring this manuscript. (Received August 20, REFERENCES (1) Brunauer, S., Emmett, P. H., and Teller, E., Adsorption of gases in multimolecular layers, .i. Am. Chem. Sot'., 60, 309-19 (1938). (2) Zettlemoyer, A. C., The pigment-vehicle interface, O.p•c. Dig., Federation Paint Varnish Prod. Clubs, 29, 1238 71 (Dec. 1957). (3) Zettlemoyer, A. C., lyengar, R. D., and Scheidt, P., Heats of immersion and water sorp- tion studies on bare and silica-coated rutile surfaces, .i. Colloid and Inte•y'ace Sci., 22, 172 8 (1966).

352 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS IFSCC CONGRESS TO BE HELD SEPTEMBER 20-25, 1970 The Spanish Society of Cosmetic Chemists will host the Sixth Congress of the International Federation of Societies of Cosmetic Chemists on September 20-25, 1970, in Barcelona, Spain. Original unpublished papers concerning the following areas of cosmetic tech- nology are now being solicited: 1. Color in cosmetics 2. Physical-chemical aspects of cosmetics 3. Biochemistry and dermatology 4. Practical science of cosmetics 5. Cosmetic regulations standardization of raw materials An International Jury will select the recipient of the S1000 IFSCC Award which will be given for the most meritorious paper presented at the Congress. To be eligible for this Award, papers must be submitted before March 20, 1970. Further information concerning manuscript requirements is available from: Sociedad Espanola de Quimicos Cosmeticos Calle Mallorca, 279 Barcelona (9) Espana