154 Royal Society : — 



which rested upon the other pole brought near the glass. The polar 

 wires from the Smee's battery of twenty-two pairs were now immersed 

 in the electrolyte on each side of the globule, and the magnet con- 

 nected with a separate battery of large surface. The direction of How 

 of the electrolyte was instantly changed to a circular one all round 

 the glass, and was reversed by reversing the polarity of the magnet. 

 In each case the direction of motion of the electrolyte corresponded 

 with that of the electric current beneath it ; i. e. with a south pole 

 beneath, the liquid moved in the same direction as the hands of a 

 watch ; — this circular motion was evidently a case of ordinary electro* 

 magnetic action, as it occurred equally well without the presence of 

 a liquid metal in the electrolyte. No real connexion of the mag- 

 netism with the movements under investigation was detected. 



20. To ascertain whether the movements varied with the quantity 

 of the electric current, I prepared a single series of sixty-six pairs of 

 Smee's batteries, forty of which were charged with spring- water, and 

 the remainder with a mixture of one measure of sulphuric acid and 

 fifteen measures of water. The movements obtained on applying 

 the current from the whole series to very dilute sulphuric acid con- 

 taining a globule of mercury, were much more feeble and the amount 

 of electrolysis much less than when the current from the twenty-six 

 strongly-charged pairs alone was applied. On substituting distilled 

 water for the dilute acid, the movements were stronger and the 

 electrolysis greater with the whole series than with the twenty-six 

 pairs. In all cases the movements appear to be dependent upon 

 the quantity of electricity circulating. 



21. It is highly probable, from the experiments just described, that 

 the movements are intimately dependent upon electro-chemical action 

 occurring at the surface of the liquid metal, especially as the amount 

 of motion varies with the quantity of electricity which passes from 

 the electrolyte into the metal, or vice versd ; and it would be very 

 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 (1 0), and only a mere 

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



