46 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS (ii) Two layer lotions. (iii) Water in oil emulsions. (iv) Aerosol hair sprays. SECTION B 4. Discuss the uses of the separate ingredients in the face powder formula given below. Suggest any improvements which you think could be made to this formula. of /o Talc 15.0 Kaolin 65.0 Precipitated chalk 5.0 Titanium dioxide 4.5 Magnesium stearate 5.0 Magnesium carbonate 1.0 Perfume 0.5 Iron oxide colours 4.0 5. You are given the job of setting up a department for the manufacture of lipsticks. Discuss the items of equipment required, and considera- tions of services, storage and layout. 6. Discuss considerations of safety-in-use of lipsticks. What studies are required in order to estimate the toxicity of a raw material for use in lipsticks ? SECTION C 7. Why is it necessary to have more than one propellant available for pressure packs ? Illustrate your answer by describing how the right balance of propellants would be arrived at in formulating a pressure packed hair spray. 8. What factors would you take into account in determining the shelf life of a brushless shaving cream to be packed into a collapsible tube ? How would you assess these factors ? SECTION I) 9. Give an account of the structure and properties of the bacterial spore with particular reference to those features which make it resistant to the action of antiseptics.

SOCIETY OF COSMETIC CHEMISTS OF GREAT BRITAIN 47 10. Outline the factors which must be considered in selecting a preservative for a toilet preparation. 11. W'at are the important micro-organisms occurring on the skin ? Discuss the relative importance of each and the selection of a germicide which may be used to inhibit their development. SECTION E 12. Describe with appropriate diagrams the structure of human epidermis. 13. Define the term 'emulsifying agent'. Describe, with specific examples, the properties and uses of the principal classes of emulsifying agents. PAPER II (Monday, 29th June 1964.) Candidates should answer FIVE questions only one question from each section. Each answer must be commenced on a separate sheet of paper or book. Where possible, express relationships and reactions in equations with a full explanation of symbols used, and give simple sketches where appropriate. SECTION A 1. Describe the experimental set up and operation of a surface balance, commenting on some typical relationships between surface pressure and areas occupied by molecules of insoluble materials. When 1 x 10 -• cc of a certain gum (density 0.9 g/cc) was compressed on a surface balance at 19øC the following values of surface pressure were obtained. Area per molecule Surface pressure (A ø•) (dynes/cm) 2800 O. 10 2061 O. 15 1700 0.20 1480 0.25 1333 0.30 By making a suitable plot assuming the film is gaseous in nature and given that the Gas Constant (R)= 8.31 x 107 ergs/mole degree calculate the molecular weight of the gum.