86 



Dr. G. Gore. 



for the sake of convenience, been made the subjects of separate com- 

 munications. (See " Effects of Electric Currents on the Surface of 

 Mutual Contact of Aqueous Solutions," " Proc. Roy. Soc," vol. 30, 

 p. 322, ibid., vol. 31, p. 250 ; " Influence of Electric Currents on Dif- 

 fusion of Liquids;" "Experiments on Electric Osmose;" "Electric- 

 Currents caused by Liquid Diffusion and Osmose," ibid., vol. 31, 

 p. 253, ibid., vol. 31, p. 296.) 



Erman, in the year 1809, appears to have been the first to observe- 

 the movements of mercury in a conducting solution while under the 

 influence of an electric current. Since that time a large number of 

 investigators have examined the phenomenon and the allied ones of 

 electric osmose, electro-capillary action, electric currents produced by 

 capillarity, the mechanical effect of electric currents upon liquids 

 and upon solid particles suspended in them, &c. Among these are- 

 Armstrong, E. Becquerel, Buff, H. Davy, Draper, Da Bois Reymond, 

 Faraday, Heidenhain, Hellwig, Herschel, Hittorf, Jiirgensen, Kuhne, 

 Lippmann, Logeman, Matteucci, Paalzow, Pfaff, Poggendorff, Porrett r 

 Quincke, Reichert, Reuss, Runge, Sabine, Serullas, Yarley, Wheat- 

 stone, Wiedemann, and Wright. It is difficult, therefore, to entirely 

 avoid restatement of some of the results arrived at by these investi- 

 gators.* I have examined the movements in relation to a variety of 

 conditions, some of which, however, are unessential and may be 

 eliminated or diminished. The phenomena have been found to be 

 purely physical, except in those cases where the electricity was of too 

 high tension and produced electrolysis, and in those in which the 

 solution acted chemically upon the mercury. 



1. Influence of the Kind and Strength of the Solution. 



The following experiments were made with the above-mentioned 

 form of apparatus, except in the instances otherwise described. The 

 electric current employed was usually (unless otherwise stated) derived 

 from two wires, one of copper and the other of platinum, each about 

 1 millim. diameter, immersed about 4 or 5 millims. deep in spring 

 water. 



Experiment No. 1. — 1 oz. of water, 40 grs. of potassic fluoride. Motion 

 occurred freely, and in the same direction as the current. 



Exjp. 2. — Various solutions of potassic chloride from 20 to 60 grs. per 

 oz. of water were tried, and in each case the movements of the mer- 

 cury were in the same directions as those of the current ; the former 

 of these solutions was too weak, it offered too much conduction- 

 resistance, and the latter too strong, it clogged the tube. With a 

 solution composed of 1 oz. of water and 40 grs. of potassic chloride in 



* A brief translation of the researches of Jiirgensen, Quincke, and Wiedemannj, 

 may be found in W. A. Miller's " Chemical Physics," 4th edition, p. 530. 



