48 Journal of the Asiatic Society of Bengal. [February, 1910. 



ally throughout and nowhere so abrupt as in experiment 



3 of the previous series. 



The curve E. in fig. 2 is plotted between the average 

 value of the e.c.e. (Ca.) given in Table III and the total time 

 corresponding to these values. The point P, at which the 

 curve meets the Y axis, gives by extrapolation the value of the 

 e.c.e. of a perfectly neutral solution, inasmuch as the acid 



time 



of current. This gives 0003045 as the approximate value of 

 the e.c.e. as read from the curve. 



Drawing F (fig. 2), the first part of curve C on the same 

 scale as E and producing it to cut the axis at Q, a similar point 

 is obtained which fixes the cathode e.c.e. approximately at 



differ from 



0003043 bv more 



The results of Table I and II seem to reveal a definite 

 experimental law with time, underlying this wide range of 

 variation in the values of the e.c.e. of nickel. It appears 

 that the only natural explanation lies in the fact that the 

 anode is not readily attacked by the acid ions liberated at the 

 time of electrolysis. The result is that, corresponding to the 

 number of nickel ions leaving the solution at any instant, the 

 number entering it is less, as these latter are supplied by 

 the anode dissolved. The sulphions, thus failing to act on the 

 anode, react upon the water forming sulphuric acid. As the 

 acid goes on accumulating with time, it draws away a good 

 portion of the current passing through the voltameter owing 

 to its higher conductivity, and an equivalent quantity of 

 hydrogen instead of nickel is deposited on the cathode. The 

 effective current actually employed in decomposing nickel 

 sulphate is therefore only a fraction of the whole current sent 

 through the voltameter, and the values of the e.c.e. based 

 upon the Ammeter readings become necessarily lower and 

 lower as the acid increases in proportion. A divided circuit 

 thus seems to be established in the electrolyte, the total cur- 

 rent branching off into the acid and nickel lines, in the inverse 

 ratio of the resistances offered by each respectively. But this 

 cannot go on indefinitely. For, with increased concentration 

 of acid, the anode gradually becomes more amenable to its 

 solvent action and begins to lose more weight than before, 



thus restoring nickel ions in Wcrpr numWa in i.ViA anlniirm and 



consequence of this 



through the nickel line. In 



gains less and the anode loses more, and the tendency is such 



as 

 thus 



Electroli tic balance will 



thus be reached at the point when the quantity of acid de- 

 veloped is just enough to dissolve away as many nickel ions 

 from the anode as leave the solution at any moment. At this 



will meet 



