Electrical charges arising at a liquid-gas interface

The various methods of studying the potential differences and electric charges which arise at the liquid-gas interface are reviewed and discussed under the following headings: - The determination of P.D. at the interface of liquid-gas when one or both of these is at rest. Cataphoresis of gas bubbles. Passage of gas over a liquid, without rupture of the latter, or of a gas over a wet solid with the same proviso. The fall of a liquid in an unbroken column through a gas. Liquid jets. Waterfall electricity. Electrification produced by bubbling gases through liquids. Electrification produced by shattering drops in an air stream. Electrification produced by spraying a liquid. An attempt is made to co-ordinate the material obtained from this vast area of research. Many of the results may be explained in terms of the modern theory of orientation and polarisation at the liquid-gas interface, but there are other facts which do not appear to come within the scope of any established principles. Suggestions are made as to possible developments in future research.