4- On the Experimental Determination of the Electro- 

 Chemical Equivalent of Nickel. 1 



By S. N. Maitra, M.A. 



Formerly Government Research Scholar, Presidency College ; 



Lecturer and Demonstrator in Physics, Presidency 



College, Calcutta. 



The following research was undertaken as a preliminary 

 to the accurate investigation of the effect of a, magnetic field 

 on electrolytes of magnetic metals. Nickel was the metal 

 chosen for the present experiments, iron being undesirable on 

 account of the readily oxidizable character of its deposits and 



as 



Previous Observations. 



It has long been known that, during electrolysis of the 

 magnetic metals, iron, nickel and cobalt, hydrogen is liberated 

 at the cathode along with the metals themselves even from 

 perfectly neutral solutions. Hittorf,* who was the pioneer 

 in the investigation of these and similar complicated cases of 

 mixed conduction, found that, in consequence, the amount of 

 these metals deposited was not by any means that which 

 might have been expected from Faraday's laws. He ascribed 

 the discrepancy to secondary reactions, some of which were too 

 complicated to be got rid of at all easily. For instance, when 

 investigating the effect of the temperature of an electrolyte 

 on the amount of the metal deposited, he found that with 

 nickel sulphate more metal is separated from a hot than from a 

 cold solution, and that even at the same temperature th» 

 amount of deposit varies considerably. 



Values given by Hittorf as well as other observers show how 

 widely the e. c. e.'s vary from one another as well as from fche 

 theoretical value as given by the product of the e.e.e. of hy- 

 drogen and the ratio of the atomic weight and valency of nickel. 



It appears that on account of these complications the 

 values of the e.c.e. of nickel which are given in text-books 

 are merely those which have been calculated from a knowledge 

 of the atomic weight and valency. 3 



Being the Elliot Prize Essay for original research for I 

 the Asiatic Society of Bengal. 



Ann. Chim. Phys., lxxxix, 1*53; also Dr. Alfred Coehn 

 3che Zeitschrift, 1891, p. 497. . 



Merrick in Journ. Chem. Soc, xL, p. 204: also in L 



xxv i . p 209. 



