The electrical conductivity and permittivity of mixtures, with special reference to emulsions of water in fuel oil

The electrical characteristics of a mixture of two substances are dependent only in part on the electrical characteristics of the individual phases. In addition to the volume ratio of the components of the mixture other factors such as particle shape and distribution have important effects on the characteristics. In this connexion an emulsion formed of a liquid with a high conductivity in one of low conductivity is free from the complications of many practical mixtures. The droplets are spheres and the system approaches the case which has been attacked theoretically with the greatest success. The characteristics of water in fuel oil emulsions have been studied both directly and indirectly by means of an electrolytic analogue. The work has drawn attention to the importance of the size distribution of the dispersed phase and has confirmed the theoretical treatments of Wiener and Bruggeman at the same time emphasizing the limitations of their formulae. This has given the work a value in applications outside the narrow field of the specialized emulsions in which it originated.