TORSIONAL PROPERTIES OF HAIR 589 useful viewpoint for considering hair behavior since helical coil tresses are often found in both waving and setting. Predictions from the theory are in general agreement with the result of experience, although deviations from ideal elastic properties and from simple systems make quantitative comparisons impossible. AC}CNOWLE•)GMENT A number of ideas and techniques for dealing with the torsional properties of hair arose from discussion with Dr. Lyman Fourt. (Received October 24, 1966) REFERENCES (1) Poynting, J. H., Thomson, J. J., and Todd, G. U., A University Textbook of Physics, 14th Ed., Charles Guffen & Company, London, 1947. (2) Champion, F. C., and Davy, N., Properties of Matter, 3rd Ed., Blackie and Son, Ltd., London, 1959. (3) Meredith, R., Rigidity, moisture and fibre structure, .1. Textile Inst. Trans., 48, T163- T174 (June 1957) The torsional rigidity of textile fibers, Ibid., 45, T489-T503 (July 1954). (4) Pierce, F. T., The rigidity of cotton hairs, Ibid., 14, T1-T17 (1923) The plasticity of cotton and other materials, Ibid., 14, T390-T413 (1923). (5) Guthrie, J. C., Morton, D. H., and Oliver, P. H., An Investigation into bending and torsional rigidities of some fibres, Ibid., 45, T912-T929 (1954). (6) Lochner, J.P. A., Measurement of modulus and damping capacity in torsion and in bending for wool and other textile fibres, Ibid., 40, T220-T231 (1949). (7) Morton, W. E., and Permanyer, F., The measurement of torsional relaxation in textile fibres, Ibid., 38, T54-T59 (1947) Torque-twist relationships in single and multiple rayon filaments, Ibid., 40, T371-T380 (1949).

590 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS S.C. C. Annual Scientific Meeting Dec. 6, 1967 The Americana Hotel New York, N.Y.