232 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS SOCIETY OF COSMETIC CHEMISTS OF GREAT BRITAIN An Exhibition of Laboratory Gadgets was held at the Royal Society of Arts on 7th April 1960. The following were shown: A simple form of Tyndallometer for the investigation of colloidal phenomena of surface active agents, and cellulose derivatives, under various conditions. Designed and exhibited by Mr. S. Castles. This apparatus was designed to show evenness of fill and correct degree of compaction in Face Powder Compacts. The depth of penetration is recorded after 10 seconds for a given load and the measurement repeated in four equi-spaced positions on the compact. The load and the cross-section of the button may be changed according to require- ments. Designed and exhibited by Dr. H. W. Hibbott. This apparatus is used for the quality control of non-Newtonian emul- sions and gels. The method is to measure the rate at which a sample of the gel is drawn into a length of precision bore glass tubing by a slight vacuum, which may conveniently be about 70 cm. head of water. The trouble-free device for obtaining a constant suction consists of a water-pump connected to maintain a constant head of water in a tube about 2 cm. in diameter. The level of water at the bottom of the tube is maintained constant by running the water from the filter pump into a bowl from which it overflows into the sink. The upper level of water in the tube is maintained by the filter pump. The precision bore tube is chosen to suit the sample. to be examined and is usually 2 ft. long and between 1 mm. and 10 mm. diameter. It is clamped vertically and is connected by a short piece of rubber tubing through a two-way cock to the source of constant vacuum. The lower end dips into the sample to be tested. It is usually sufficient to keep the sample in a thermostat or constant temperature cupboard for temperatures near the ambient but, when greater accuracy is required, the precision tube also may have a constant temperature jacket. A most important aspect is that it can be completely defined

SOCIETY OF COSMETIC CHEMISTS OF GREAT BRITAIN 233 in a specification. Since precision bore glass tubing is now readily obtain- able the apparatus can be accurately reproduced. In control work it is sufficient to time the arrival of the sample at two or three points along the tube, but the non-Newtonian character of the flow is best seen from a complete curve of distance against time. Designed by Dr. B. D. Sully. Exhibited by Mr. G. 3/1. Howard. . SENSITIVE INIEPHELOMETER. This instrument works in the range of low light scattering and although it was originally designed for biological work it is also very suitable for testing the clarity of high-quality tiltrates. Designed by Mr. N. V. Needham of the Cooper Technical Bureau. Exhibited by Mr. E. J. Miles. GLUE JELLY TESTING APPARATUS. This instrument was designed as a simplification of the Standard Bloom Gelometer against which it can be readily calibrated to give values in standard units. Designed by Mr. R. Barry Drew of British Glues and Chemicals Limited. Exhibited by Mr. E. J. Miles. OPTICAL ANISOTROPY VIEWER. This is a simple and convenient means of examining liquids for streaming birefringence in colloid systems. Designed by Dr. P. A. Winsor of the Shell Chemical Company. Exhibited by Mr. E. J. Miles. PHOTOMETER. Many cosmetic products are dispersions of one phase in another as, for example, liquids in liquids giving emulsions or solids in liquids giving suspensions. When light is passed through a thin film of a dispersion, it is scattered by an amount depending on the phase volume relationship, the degree of dispersion and the difference between the refractive indices of the dispersed and the continuous phase. For a system of constant composition, the amount of light scattered will therefore be determined by the degree of dispersion of the discon- tinuous phase. Thus, provided the droplets are not of colloidal dimen- sions, an emulsion in which the droplets are finely dispersed will scatter