An emulsion is a dispersion of one liquid in another liquid, the liquids being insoluble in each other. An emulsion consists of two phases, a continuous phase and a dispersed phase. The dispersed phase consists of tiny droplets or particles of one liquid which is completely surrounded by the other liquid comprising the continuous phase. One of the many factors affect­ing the stability of an emulsion is the size of the particle
of the dispersed liquid.

This study is concerned with one emulsion prepared by different mechanical devices and under different conditions. The units of equipment employed are Eppenbach Colloid Mill, Marco Homogenizer, Lightnin' Mixer and Master Counter-current Mixer. Samples of the emulsion prepared by these methods will be retained for particle size determinations. All samples will be stored in a constant temperature room at 70° F.

The ultimate aim of this study is to indicate the effectiveness of each of the emulsifying units studied. It is also desired to show how the particle size of the dispersed phase changes on aging. The stability of all samples was closely followed to discover any trends of instability.

A search of the literature reveals only fragments of information concerning particle size analysis with regard to commercial preparation of emulsions. In the previous work on emulsions, standard laboratory methods of dispersion were usually used. It is hoped that this study combined with past and future studies will point to some definite mechanical system to produce the optimum commercial emulsion.