with the Mercury Cathode. 



plated anode, and consequently the conditions of electrolyses 

 not comparable. 



After two additions of approximately 2 c,nS portions of salt 

 solution the current would not decrease to as little at *03 amp. 

 even when the electrolysis of the third 2 ora3 was continued from 

 2 to 4^ hours. Upon the failure of the current to fall to '03 

 ampere the inner cell liquid was siphoned out, the anode heated 

 to free it from oxide and the electrolysis continued with a fresh 

 2 cm3 portion of the salt solution. 



As seen from the data of the experiment in Part 2 of Table 

 Y the electrolysis ran, in all, nearly 18 hours and '0162 grms. 

 of silver were recovered from the mercury by distillation. 

 Comparing this experiment with those recorded in Part I it 

 would seem to make little difference as to whether the anode 

 was pure silver or silver plated if the transfer to silver to the 

 cathode is alone considered. 



No experiments were made to determine the best analytical 

 conditions for the use of this pure silver anode, those having 

 been satisfactorily worked with the more efficiently sized and 

 shaped silver plated platinum electrode. 



Conditions for Analysis. 



The matter in the foregoing pages may now be used to 

 determine the best conditions for the electrolysis of 50 cra3 of 

 •IN sodium chloride solution using the apparatus at hand and 

 4 storage cells. What the proper conditions would be with a 

 sodium chloride solution of different strength with an appara- 

 tus of slightly different dimensions or under different current 

 conditions, the author feels, would have to be determined by 

 preliminary experimentation. 



The ammeter cannot be relied upon, without previous experi- 

 mentation, to determine the end of the electrolysis, as the cur- 

 rent, during the operation, falls gradually from the start to an 

 indefinite end. There is no rapid decrease in the ammeter 

 reading at any point to indicate the complete decomposition 

 of the sodium chloride, the accumulation of the alkali in the 

 inner cell being sufficient to carry considerable current mean- 

 while. 



Procedure. — The procedure, then, for the quantitative elec- 

 trolysis of "2923 grms. of sodium chloride in 50 cm3 of water 

 would be as follows : Introduce about 2 kg. of mercury into 

 the apparatus or sufficient mercury to rise 6-8 mm above the 

 bottom of the inner cell. Cover the nickel wire with water 

 (70-80 cm3 ) and add to it l cra3 of saturated salt solution. Intro- 

 duce the 50 cm3 of salt solution (-2923 grams NaCl) into the 

 inner cell and electrolyze with the bottom of the anode 6-10 mm 

 above the surface of the mercury. The current should be 



