284 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS to car-2-ene with palladised charcoal and hydrogen. Both show the same sort of conjugation in their uv and ir spectra arising from overlap of n-systems. DR. G. P. Moss: Have you tried the hydrogenation of carenes with homo- geneous catalysis? It is well known that this method does not normally encourage isomerisations. THE LECTURER: No, though we have it very much in mind. Me. J. MCIVER: I saw no mention about the odour value of the numerous com- pounds produced in this extensive work. Has any work been carried out on the odour of the materials are any of these compounds particularly useful to perfumers? THE LECTURER: We have not done anything of this sort, though we have passed on materials for evaluation to some of our friends. To us, who are not perfumers, the caranols have modified menthol odours. Likewise the ketones have modified menrhone odours. I think that many of our products would merit professional evaluation. MR. MCIVER: Do any show promise at all? THE LECTURER: I have not received any information about our products. Evalua- tion, for perfumery purposes, is something which was outside the scope of our work and I have left it to others to carry out these evaluations.