ON ELECTROLYSIS. 345 



passing a current through a mixture of dilute sulphuric acid and a salt of 

 strontium. It is well known that a precipitate does not come down for some time, 

 and that such time is shortened by heating.' He then describes an experiment that 

 is practically the same as my own, for which he used five Bunsen cells, and a 

 similar experiment with a potassium salt and tartaric acid, and in both instances he 

 obtained an acceleration, as I did. He adds, however, a somewhat diflerent experi- 

 ment. Cyanide of potassium was added to a solution of a nickel salt, and the first 

 precipitate was redissolved in excess. Then hypochlorite of sodium was added. 

 On boiling such a mixture, or allowing it to stand for some time, a black precipitate 

 appears ; but the moment the electrodes were inserted in a portion of the mixture, 

 although cold, a black cloud was formed. 



More recently Mr. Enright, at my suggestion, tried the efiect of varying the 

 strength of current. Using a mixture of strontium chloride and sulphuric acid, 

 which would give a turbidity in about seven minutes without the current, he found 

 that when exposed to the influence of seven cells the turbidity appeared in four 

 minutes, of six cells about the same, of five or four cells in four minutes and a half, 

 of three cells in six minutes, while two cells did not produce any acceleration that 

 could be distinctly recognised. 



On repeating my experiments lately the general results were confirmed, but I 

 failed to secure the conditions under which the line of precipitate between the 

 poles is produced. 



These experiments seem in accordance with what might be expected if the 

 electrolytic action takes place through the interchange of the radicals of the 

 dissolved salts. 



Oil Ohm's Law in Electrolytes. 

 By G. F. Fitzgerald, F.B.S., and Feed. Trouton, Trin. Coll. Dub. 



The result of our experiments up to this is to ascertain that ' h' in 

 [y = Vq{1 - he-)'] is certainly less than 5 x 10~^. 



This time last year it was hoped shortly to attaia much greater accuracy than 

 had then been reached, but it is clearer now than then what a difficulty the ' heat- 

 ing efiect ' is. 



This inherent difficulty in studying Ohm's Law of liquid electrolytes, as com- 

 pared with metallic conductors, may best be understood by considerino- the in- 

 creased difficulty which would be introduced in the determination for metals if the 

 wire were to be immersed in an electrically non-conducting liquid. When the 



wire loses heat, chiefly by radiation, as when in air, its general temperature is so 

 inuch above the temperature of surroundings that its rate of cooling may be con- 

 sidered constant for the small changes of temperature which can occur if the alter- 

 nations from the larger to the smaller current be sufficiently frequent. The tem- 

 perature thus rises at a constant rate while the larger current runs, and so falls 



