1861.] 227 



23. Raising the temperature of the solution to atout 200 Fahr. 

 appeared to have no direct effect upon the vibrations, it only affected 

 them indirectly by allowing more electricity to circulate. The appa- 

 ratus employed for hot solutions was that shown in fig. 7 (15). 



Influence of the Electric Current. 



24. In nearly all cases the vibrations and sounds were essentially 

 dependent upon the passage of the electric current, and ceased the 

 instant the current was stopped ; the exceptional cases being those 

 already mentioned (10), in which the sounds continued a short time 

 after the current was stopped : it is probable that in those cases local 

 electric currents were produced by the action of the water upon a 

 minute quantity of potassium contained in the mercury, and which 

 had been deposited by the previous electrolysis. 



25. With regard to the influence of the direction of the electric 

 current ; the vibrations and sounds only occurred where the current 

 passed from the electrolyte into the metal, never (or very rarely, and 

 under conditions which I have not recently met with) where it passed 

 from the metal to the solution. No direct effect of the direction of 

 the current in the mass of the electrolyte upon the crispations was 

 detected by passing the current either vertically or horizontally 

 through the solution into the cathode. 



Influence of Size and Number of the Voltaic Elements. 



26. Twenty Smee's elements, 2^ inches wide, and immersed ^thof an 

 inch deep, with a mercury ring If inch diameter and -j^ths of an inch 

 wide, gave crispations ^th of an inch wide, and a coarse base sound ; 

 whilst four Smee's elements, 1\ inches wide, and immersed 9 inches deep 

 in the same acid mixture, gave, with the same ring, fine crispations 

 about ^nd of an inch wide, and a high tone ; and one Grove's cell, 

 with a platinum plate 12 inches wide and 18 inches deep, and the 

 same ring, gave very faint sounds of high tone without visible cris- 

 pations in the negative ring, and with fine crispations if the pool of 

 mercury formed the cathode. The crispations produced by the 

 twenty small Smee's cells (charged either with acid 1 to 8 or 10 of 

 water or 1 to 24) were less regular than those produced by ten ele- 

 ments of the same surfaces, or five pairs of the larger elements. 



27. The least number of Grove's cells, containing platinum plates 



