243 



desirable to obtain a negative proof of this by an experiment with a 

 globule of one liquid metal in a bath of some other liquid metal, as 

 already attempted (12). 



22. With every liquid yet examined the movement of the liquid 

 has invariably been attended by a simultaneous movement of the 

 fluid metal ; and the greater the movement of the liquid the greater 

 was the movement of the metal, from which I infer that the move- 

 ments of the two substances are mutually dependent. 



23. The results in general indicate that the sudden movements 

 are of the same general character as the continuous ones, the effect 

 in the former case being heightened by the concentration of the 

 electric force within a small compass, together with the additional 

 electric energy always displayed at the moment of making contact 

 with a battery. 



24. The movements require for their production two substances 

 (6) ; both these substances must be in a liquid state (7), and be 

 conductors of electricity (8) ; one of them must be a metal or a 

 metallic alloy (9) ; any metal or alloy will do (10), and only a mere 

 film of it is essential (11); the other must be an electrolyte, and 

 need not contain water (13) : any electrolyte will do (14), and only 

 a thin layer of it is requisite (15) : the electric current must pass 

 from the electrolyte into the metal, or vice versd (16), but need not 

 pass both into and out of it by the electrolyte (17); the electrodes 

 are not essential (18) ; the movements are not electro-magnetic (19), 

 they are dependent upon the quantity of the electric current (20), 

 and are intimately connected with electro-chemical action (21) ; the 

 movements of the metal and electrolyte are mutually dependent (22), 

 and the momentary movements are of the same nature as the con- 

 tinuous ones (23). 



25. The pure or abstract conditions of the production of the phe- 

 nomena are, a liquid metal (or alloy) in contact with a liquid elec- 

 trolyte, and a quantity current of electricity passing between them. 



B. Conditions of the continuance of the Movements. 



26. With regard to the continuance of the movements: 1st. 

 In some cases the metal becomes covered with an insoluble film, 

 produced by ordinary chemical action of the liquid, which prevents 

 the continuance of the action ; this occurs particularly with mercury 

 in strong solutions of sulphides, iodides, bromides, and chlorides. 



