382 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS utility, since questions of providing adequate seals, effective and strong hinges and snap closures, strong and efficient threads, location of trade marks and advertising marks must always influence the overall design. When considering designs for new products using plastics it is important to remember that they are not substitutes for other materials formerly used. Even so, it is not easy to step out boldly without previous experience, and we inevitably find that design is often a process of trial and error until confidence has been acquired. The basic problem of the plastics industry is deep down: it is newness. Some of the materials the industry works with are so new that engineers and chemists still have not tested them thoroughly or found out what can be done with them. The typical plastic is more expensive than the older materials even the cheapest of the plastics (polystyrene and polythene) are more expensive on a pound-for-pound basis than steel, rubber, glass, cast iron or wood. Most plastics' success depends on their ability to dodge competition with other materials entirely and to develop along their own lines, often using methods of production that nobody has used before. The products of the industry have been variously described as "wonder materials" and the stuff that dreams are made of, and in almost the same breath as cheap and shoddy substitutes. The latter term often results from faulty design of the end product, and one of the things to guard against is that of putting plastics into jobs where they might fail because of insuffi- cient appreciation of all the factors concerned. I would like to thank the Directors of British Resin Products for permis- sion to give this paper and my colleague, Mr. D. N. Davies, for his help in preparing it.