20 Mr. J. Napier on Electrical Endosmose. 



forty-one hours, deposited upon pole 29 grains, being 3*4 

 grains more than the equivalent of 100 grains of sulphate, 

 which is equal to 8*5 grains of sulphate which have passed by 

 endosmose, not including water of crystallization, as I believe 

 the salt passes without water. The negative solution had in- 

 creased in bulk 1 ounce. 



With a 2-pair battery the negative solution exhausted in 

 nineteen hours, deposited upon pole 32 grains, being 6*4 

 grains more than the equivalent of 100 grains of sulphate, 

 and equal to 16 grains of sulphate passed by endosmose. 

 The solution had increased in bulk five-eighths of an ounce. 

 With a 4-pair battery the negative solution exhausted in 

 twelve hours, deposited upon pole 35*6 grains, being 11 grains 

 more than the equivalent of 100 grains of sulphate, and equal 

 to 27*5 grains of sulphate passed by endosmose. The solu- 

 tion had increased half an ounce. 



With a 6-pair battery the negative cell exhausted in seven 

 hours, deposited upon pole 39 grains, being 14'4 grains more 

 than the equivalent of 100 grains of sulphate, equal to 36 

 grains of sulphate passed by endosmose. The solution in- 

 creased in bulk three-eighths of an ounce. 



The two divisions of the decomposing cell were now charged 

 with distilled water; two platinum electrodes were used; the 

 current was also made to pass through a solution of sulphate 

 of copper to ascertain if sufficiently strong to effect any de- 

 composition ; but in none of the experiments was any deposit 

 obtained. Each experiment was continued thirty hours, when 

 the cells stood thus : — 



With one pair, positive lost 1 oz. negative gained f oz. 



... two pairs 1 oz. ... ... f oz. 



... four pairs 1^ oz. ... ... § oz. 



... six pairs 1| oz. ... ... lX oz. 



... nine pairs 1 ;', oz. ... ... If oz. 



With these, and all other experiments with water, a similar 

 vessel to the decomposing cells was placed alongside, filled 

 with water, to note the loss by evaporation, which in this case 

 was three-eighths of an ounce, accounting for the loss in the 

 two cells above. 



A similar experiment was made with thirteen pairs of a 

 Grove's battery, the current passed four hours ; a gentle flow, 

 of gas was evolved from the electrode. No copper solution 

 was used in this experiment. The cells stood thus : positive 

 lost 2 ounces, negative gained If ounce. 



The two divisions of the decomposition cell being again 

 filled with distilled water, into one was put a piece of zinc 

 and into the other a piece of platinum, connected by a wire ; 



