SMOKE AND DUST ABATEMENT COTTRELL. 665 



by Alfred O. Walker of the above firm in several countries,' but these 

 patents have long since expired. The apparatus was installed in 

 1885 by the works manager, W. M. Hutchings, with the cooperation 

 of Prof. Lodge, and was briefly described by the former ^ just before 

 its completion as consisting of a system of metallic points situated in 

 the flue from the lead furnaces, and excited fi'om two Wimshurst 

 influence machines with glass plates 5 feet in diameter, each machine 

 being driven by a 1 -horsepower steam engine. Figure^ 1 reproduces 

 the drawing accompanying Walker's United States patent specifica- 

 tion, A being the Wimshurst machine and B the flue carrying the 

 gases to be treated. 



The apparatus undoubtedly did not in practice fulfill expectations, 

 as we find nothing further of it in the literature. The most apparent 

 weakness of the project lay, perhaps, in the reliance on the Wims- 

 hurst machine, which had then just been brought out and fi-om which 

 a great deal more was anticipated* than has been justified hj expe- 

 rience, at least as far as commercial applications are concerned. 

 Almost simultaneously with Walker, and apparently without knowl- 

 edge of his and Lodge's work. Dr. Karl Moeller, of the firm of 

 K. & Th. Moeller, of Brackwede, Germany, secured a patent ° on 

 electrical precipitation. The patent specification itself appears, how- 

 ever, to be the only published record of this work. The idea was, it 

 is understood, suggested by an article" dealing with the disturbing 

 influence on electrometer measurements due to dust in the air. 



After this an occasional patent' or article ^^ served to keep the 

 subject in the public eye, and in 1903 Lodge took out a patent^ 

 covering the use of the then new mercury arc for rectifying high 

 potential alternating currents for this purpose, but none of these 

 patents seem to have been carried into successful commercial opera- 

 tion on the large scale in the chemical or metallurgical industries. 



Some eight years ago, while studying various methods for the 

 removal of acid mists in the contact sulphuric-acid process at the 

 University of California, the author had occasion to repeat the early 

 experiments of Lodge and became convinced of the possibility of de- 



1 Great Britain, Patent No. 11120, Aug. 9, 1884; Belgium, 68927, May 19, 1885; Spain, 

 7211, July 10, 1885 ; Germany, 32861, Feb. 27, 1885 ; Italy, 18007, Mar. 31, 1885 ; 

 United States, 342548, May 25, 1886. 



2 Berg.- und Hiittenmannisch Zeitung, vol. 44, pp. 253-254 (1885). 



3 The figures in this paper are numbered consecutively and printed on plates. 



•'A. 0. Walker, Engineering (Lend.), vol. 39, pp. 627-628 (1885). G. Tissandier, Lon- 

 don Electrician, vol. 17, p. 33 (1886). 



!^Ger. Pat. 31911, Kl. 12, Oct. 2, 1884. 



«By Robt. Narwald, Wied. Ann. vol. 5, pp. 400-499 (1878). 



'Lorrain, British Pats. 6495 and 6567 (1886); Thwait, U. S. Pat. 617618, Jan. 10, 

 1899; Hardie, U. S. Pat. 768450, Aug. 23, 1904; Blake, U. S. Pat. 913941, Mar. 2, 1909; 

 Dion, 925626, June 22, 1909. 



«J. Wright, Elect. Rev. <;Lond.), vol. 47, p. 811, Nov. 23, 1900; see also .lour. Roy. 

 Sanitary Institute, vol. 27, p. 42. 



"Brit. Pat. 24305 (1903) ; U. S. Pat. 803180, Oct. 31, 1905. 



