Electrical Fume-precipitation.

(New York Meeting, February, 1912.) ABOUT a year and a half ago, at the San Francisco meeting of the American Chemical Society, in connection with the excursions to local smelting-works, I had occasion to show some lantern-slides illustrating the recent commercial development of electrical methods for precipitating the suspended matter from smelter-smoke, the underlying phenomena of which were clearly brought to the attention of the technical public by Sir Oliver Lodge as long ago as 1884. In the Journal of industrial and Engineering Chemistry, August, 1911, most of these views were reproduced, together with an account of the work from its beginning up to July, 1911. To-day I wish particularly to show you some of the further developments of the work since that time; but in order to make these clear they will be prefaced by a brief abstract of the article above referred to. The removal of suspended particles, front gases, by the aid of electric discharges is by no means a new idea. As early as 1824 we' find it suggested by Hohlfeld 1 as a means of suppressing ordinary smoke, and again a quarter of a, century later by Guitard.2 These suggestions, which do not seem to have stimulated any practical study of the question, were soon entirely forgotten, and only brought to light again by Sir Oliver Lodge,3 many years after he himself had independently rediscovered the same phenomena and brought them to public attention 4 in a lecture before the Liverpool Section of the So-