364 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS I sincerely hope that this paper will contribute towards your under- standing of the ever-growing field of pressurised or aerosol packing, and I wish to thank Mr. W. S. Manson, of the Cooper Technical Bureau, for the loan of slides showing various aspects of the PAFCO plant Mr. M. N. Conville, of Safca Aerosol Manufacturing, Ltd., for the loan of a slide showing the Satca filling plant Mr. W. C. Botfield, of W. J. Bush & Co., Ltd., for generously providing a quantity of the handcream formulation referred to in the paper last, but not least, my sincere thanks are due to the indefatigable Jack Pickthall, of Polak and Schwarz, for his many helpful suggestions. In conclusion, I record my thanks to the Directors of the Metal Box Co., Ltd. to Mr. R. K. Sanders, Director of Research, and to Mr. J. H. Brittain for permission to present this paper. REFERENCES • Shepherd, H. R., Amer. Perfum., Aug., 1954, 121. • D.R. Pat. 532,194. a D.R. Pat. 557,259. 4 Soap, N.Y., December, 1955, •tl, 209. * U.S. Pat. 2,321,023. 6 Reed, F. T., J. Soc. Cosmet. Chem., 1956, ?, 137. * Witjens. P.H. Private communication. 8 U.S. Pat. 2,705,661. • Mina, F. A., Drug Cosmet. Ind., 1956, ?8, 254. •0 Reed, F. T., KTM-18, "Kinetic Chemicals Division," E. I. du Pont de Nemours & Co., Inc., Wilmington, Del., U.S.A. n KTM-17, "Kinetic Chemicals Division," E. I. du Pont de Nemours & Co., Inc., Wilmington, Del., U.S.A. • Wells, F. V., Soap, Perfum. Cosrn., 1955, 28, 1271. •a Poole, J. J., and Steuernagle, J. H,, "Glass Containers as Packages for Low Pressure Aerosols," Brockway Glass Co., Inc., Brockway, Pa., U.S.A. •4 Verpackung Rdsch., 1956, 7, 122. •* U.S. Pat. 2,686,081. 2• Mod. Packag., November, 1955, 29, 98. 27 Br. Pat. 740,635. is Herzka, A., Chem. andInd., 1956, 6. 29 Aerosol News, 1, 4, "Kinetic Chemicals Division," E I. Du Pont de Nemours & Co., Inc., Wilmington, Del., U.S.A., •.o The GivaudanJan, April, 1955, 3. • The Givaudanian, May, 1955, 9. •' The Aerosol, Polak & Schwarz (England), Ltd., Enfield. •a Aerosols, N.V. Chemische Fabriek "Na•.rden," Bussu m, Holland. •.4 Pickthall, J., Parf. Cosmalt. Sayohs, No. 121, March, 1956, 85. 2, van Beem, J.G. Private communication. 2• Ruys. A. H. Private communication. •? Silicone Notes G6-1, March, 1955. Midland Silicones Ltd., London, W.1. •8 Curfie C. C., and Gergle, R. C., Soap, N.Y., January, 1956, $2, 98. •9 Philips, H. G., Jnr., Drug. Cosmet. Ind., 1954, 75, 30. s0 Greenfield, I., Indust. Chem. Mfr., 1956, $2, 11. sx Schimmel Briefs, N. Y., No. 233, August, 1954. as Drug. Cosmet. Ind., 1956, 78, 383. aa Perfum. Essent. Oil Rec., 1955, 46, 350. a4 Soap, Perfum. Costa., 1955, 28, 1117. a• Root, M. J., J. Soc. Cosmet. Chem., 1956, ?, 162. s0 Root, M. J., J. Soc. Cosmet. Chem., 1956, 7, 153.

BOTTLE CLOSURES 365 BOTTLE CLOSURES A Lecture delivered to the Society on Thursday, January 5th, 1956 S. F. TOWNSEND.* The author gives details of the make-up of the many varieties of bottle closure. He discusses their advantages and disadvantages for the different purposes for which each is customarily used. FUNDAMENTALLY, closures, as the term is commonly interpreted, can be divided into two types, these being plugs and screw or snap-on caps. To deal with the first, closures of the plug type in common use are corks, glass stoppers, rigid compound screw stoppers with rubber rings, rubber plugs, polythene stoppers and porcelain swing stoppers with rubber rings. A feature of all plug type closures that should be recognised is that all types occupy internal space in containers, and to a varying degree compress the air space or vacuity in containers. For some bottling purposes this is of little consequence, but with the bottling of volatile liquids or where there is little air space in containers this feature must be considered. In regard to this, a general principle that is practised in the wine and spirit bottling trade is to allow 3• to 4 per cent of closure volume as air space so far as the bottle manufacturers are concerned it is recognised practice to do this. CORKS As we know them these are by far the most commonly used of plug-type closures. The manufacture of these is a specialised craft which is largely centralised in Portugal and Spain. The cork wood from which they are made originates from the cork oak (Quercus suber), which is tound in various Mediterranean countries, the largest concentrations being in Portugal, South Spain, and the coastal belt of North Africa. Cork wood is oi microcellular structure, the air space being about 50 per cent of total volume. The solids in the main are composed of ligneous tissue, organic acids such as tannic acid, and resins. The moisture content is normally between 2 and 6 per cent. It is affected by strong acids and alkalis, also it is, in effect, slightly porous to volatile solvents. However, it withstands ageing very well and has been found satisfactory for a multitude of closure purposes. Normal corks are punched so that pores run across and not from tip to top. In use this prevents seepage of bottled liquids through pores. The only exception to this are large corks or bungs that are used on carboys and jars these are cut with the outside of cork bark on top. * Armstrong Cork Co., Ltd., London, N.W. 9.