LOOKING AT THINGS however, if the amount of alkali is carefully controlled, as it should be, then if one, for the purpose of painting the picture, assumes that the amount of alkali is equivalent to half the total stearic acid, then, statistically, the inter- facial film will be composed of alternate bridges of sodium soap and of stearic acid. This interface will, therefore, be more likely to be uniform in texture so that it will tend to be strong and probably have few flaws in its "crystalline structure." Another method would be to dissolve the soap together with the free stearic acid in the oil phase and then add the water. In such a system as this, the soap molecules will be pushing out further from the surface of the oil than the unneutralised stearic acid, so that when water is added there will be a preferential superabundance of soap (sodium stearate) at the inter- face tending to squeeze out the unneutralised stearic acid from the interface. Such an interface will be unlikely to be as strong as one produced when the acid soap is formed in situ. Finally, if the soap is dissolved in water together with the free stearic acid, then because soap is a colloidal electrolyte and tends to associate with stearic acid forming micelies, the added oil may not easily break-up the micelles so that the free stearic acid is bound in the form of an acid soap and will have great difficulty in reaching the interface to help form a mosaic. In fact, the oil would slowly penetrate the micelle and associate with the oleophilic chains within. The chances are, therefore, that the first method is the best the third procedure will probably produce the most unstable emulsion. Looking at the problem in this way one can begin to appreciate that a soap produced by half-neutralising a fatty acid may not be quite the right proportion, and many instances are known where the most stable cream of this type is produced when the fatty acid is only about quarter-neutralised. A good example of this is to disperse 10 per cent of oil in water by means of stearic acid, sodium hydroxide and cetyl alcohol, the cetyl alcohol being employed as the stabiliser of the emulsion. If the molecular ratio of sodium hydroxide to free stearic acid is greater than one to three, although the emulsion may form quite readily, it will not be stable and will readily cream. Furthermore, the maximum body of the emulsion will be obtained when the amount of base neutralises about one-quarter of the stearic acid. Another instance of the way "good looking" can assist is in the simple case of dissolving a hydrophilic colloid, such as gelatin. If one takes a sheet of dry gelatin and puts it into boiling water the solution or dispersion of the gelatin may not be complete for several hours. Consideration of the pro- blem will indicate that when the dry gelatin meets hot water the gelatin tries to dissolve, but because the water cannot penetrate the dry material the dissolution takes place purely on the outside and takes time, in so far as the dissolving gelatin blocks the intermolecular spaces. On the other 155

JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS hand, one should realise that when gelatin is placed in cold water, in which gelatin does not dissolve, the water, in diffusing into the sheet, causes the gelatin to swell so that the intermolecular spaces are enlarged and the water molecules will not get jammed at the surfaces. Even a relatively thick sheet of gelatin will soften and swell in cold water in a comparatively short space of time. Only when the gelatin has fully imbibed water should heat be applied. Under these conditions, as soon as the temperature reaches the melting point of the swollen gelatin, the whole mass will quickly disperse. Solving the "why" and the "wherefore" brings us now to the quintessence of looking. Nobody imagines for one moment that Isaac Newton was the first man to see an apple fall. It is true, however, to say that he was the first man who really looked at an apple falling because he started to ask himself questions as to why all apples fall and, indeed, all heavy things behave in a similar manner. He observed that it was a characteristic of nature and, being Newton, he was able to see that the falling of the apple was due to an attractive force existing between two masses. It is all very simple now, and although even before Newton's time the principle of failing weights was employed as a source of energy, it was done merely by virtue of experience and not by knowledge. What it really comes to is that the observant and thoughtful person, whenever he sees something happen, always enquires of himself why did it happen. If he is a good scientist he will not let his mind forget that happening until he has produced a hypothesis to explain in a reasonable manner the phenomenon. What all this really means is that every time one looks at anything, veritable avalanches of messages should be passing from the eye to the brain, from the brain to the eye, so building up a complete co-ordinated picture. It is this form of approach which produced the craftsman of the past. Although he is being succeeded by the scientist, the methods must still remain true in principle, and the task of the industrial scientist is to transpose these observations into figures or values. By such a means of notation it becomes possible not exactly to dispense with the craftsman, but by having scientific data one is able to make experience permanent. The chemist in the factory has the great chance. Most products--cer- tainly those made by reputable firms--are good, even very good. Since no one should ever be content to rest on his laurels, it is necessary to aim at better quality produced by a simpler technique or an alteration in formula, etc., etc. Because it is impossible to make a tremendous improvement in something which is already very good, means have to be devised so that the improvement can be determined. It is clearly to be seen that such variations can be determined only by a statistical examination of values relating to quality. It is almost certain that every chemist records all his analytical data relating to quality control. Often such information is meticulously 156