110 Gooch and b\ iser — Silver by Electro-Deposition 



Table I. 



The Electrolysis of Silver Nitrate dissolved in Ammonium Oxalate and 



Ammonia. 



Ag in 









Current 







Revolu- 



AgNO s 



Ag 





, 



1 



, 





tions 



taken 



found 



Error 





Approx. 





Time 



per 



grm. 



grm. 



grm. 



Amp. 



N. D. 



Volt 



min. 



min. 







A crucible used as 



cathode. 









(1) 0-2687 



0-2685 



-0-0002 x 



1-5-1 



5-3-3 



6-7 



25 



500 



(2) 0-2687 



0-2687 



±0-0000 x 



1-5-1 



5-3-3 



6-7 



30 



500 



(3) 0-2687 



0-2684 



-0-0003 x 



1-0-5 



3-3-1-7 



6-7 



30 



450 



(4) 0-2087 



0-2685 



-0-0002 x 



1-0-5 



3-3-1-7 



4-6 



30 



450 



(5) 0-3183 



0-3181 



-0-0002 x 



1-5-1 



5-33 



4-6 



20 



450 



(6) 0-3183 



0-3178 



-0 0005 + 



1-5-1 



5-3-3 



4-6 



10 



450 







Gauze discs used as 



cathode. 









(7) 0-3183 



0-3179 



-0-0004 x 



1-0-5 



0-5-0-25 



4-6 



20 



400 



(8) 0-3183 



0-3182 



-0-0001 x 



1-0-25 



0-5-0-10 



6-8 



25 



400 



(9) 0-3183 



03181 



-0-0002 x 



1-0-25 



0-5-010 



5-8 



25 



400 



(10) 0-3183 



0-3180 



-0-0003 x 



0-75-0-25 



0-4-0-10 



5-7 



40 



450 



(11) 0-3183 



0-3180 



-0-0003 x 



1- -0-25 



0-5-0-10 



4-6 



40 



450 



(12) 0-3183 



0-3176 



-0-0007 + 



0-75-0-25 



04-0-10 



6 



20 



450 







Gauze cone used as 



cathode. 









(13) 0-2687 



0-2686 



-0-0001 x 



1-5 -1 



3-2 



4-6 



25 



500 



(14) 0-2687 



0-2683 



-0-0004 x 



1- -25 



2-0-5 



6-7 



30 



450 



(15) 0-2687 



0-2684 



-0-0003 x 



1- -5 



2-1 



4-6 



25 



450 



(16) 02687 



0-2686 



-0-0001 x 



1- -0-25 



2-0-5 



4-6 



25 



450 



(17) 0-5375 



5373 



-0-0002 x 



1-5 -1 



3-2 



6-7 



25 



450 



(18) 0-5375 



05371 



-0-0004 x 



1-5 -1 



3-2 



6-7 



25 



500 



x Deposition complete, as shown by H 2 S test. 

 + Deposition incomplete, as shown by H 2 S test. 



deposit is naturally more adherent when the cathode surface 

 is relatively large and the current density low. When the 

 current density is high the deposit is apt to be voluminous, 

 shrinking considerably upon drying, and this phenomenon 

 was especially notable in the case of the deposits upon 

 a comparatively small and smooth surface of the crucible. The 

 best form of apparatus appears to be the gauze coue set point- 

 downward and so placed with relation to an annular platinum 

 band used as the anode that the end of the axis where the 

 centrifugal effect of rotation is least shall not receive much of 

 the deposit. Experiments made with stationary gauze elec- 

 trodes were not successful nor were those made with a dish 

 cathode and stirring anode. 



Other experiments in which the silver was first precipitated 

 as silver chloride and then deposited from the solution in 

 ammonia and ammonium oxalate are given in Table II. In 

 these experiments, in which the solutions were more strongly 

 ammoniacal than those of the experiments of the preceding 

 series, the deposits were dark and spongy, but they became 

 lighter in color and more compact upon drying. 



