Electrolytic Determination of the. Metals. 



323 









Table D. 











Silver 



Silver 













taken. 



found. 



Error. 



Current 



ND 







grm. 



grm. 



grm. 



amp. 



100. 



Time. 



1 



0-0968 



0-0966 



— 0-0002 



1-8 



6 



15 min. 



2 



0-0968 



0-0967 



—o-oooi 



1-9 



6-3 



15 " 



3 



0-0968 



0-0965 



— 0-0003 



1-8 



6 



15 a 



4 



0-0968 



0-0969 



+ 0-0001 



2 



6-7 



10 " 



5 



0-0968 



0-0965 



— 0-0003 



3 



10 



8 " 



6 



0-1898 



0-1901 



+ 0*0003 



2-5 



8-3 



10 " 



7 



0-1898 



0-1898 



+ 0-0000 



2-5 



8-3 



10 " 



8 



0-1898 



0-1900 



+ 0-0002 



3- 



10 



10 " 



9 



0-1898 



0-1893 



— 0-0005 



2-5 



8-3 



10 " 



The rapid deposition of nickel was equally successful. 

 Nickel-ammonium sulphate was dissolved in 25 cm3 of water and 

 2Qcm3 £ s ^ rori g ammonia were added. In this liquid about a 

 gram of ammonium sulphate was dissolved and the solution 

 was treated in the same manner as in the preceding experi- 

 ments upon copper and silver. It should be especially noted, 

 however, that the solution must be kept within the limits of 

 volume indicated above, as further dilution lengthens the time 

 necessary for complete deposition. 



Table E. 



Error. 



grm. 



0-0000 



— 0-0001 

 + 0-0002 



—o-oooi 



+ 0-0001 



— 0-0002 

 + 0-0002 

 + 0-0002 



— 0-0001 

 0-0000 



From these results it is plain that nickel, like copper and 

 silver, may be deposited with rapidity and completeness. 



The metallic deposits of these metals obtained by means of 

 the revolving cathode are sufficiently coherent and compact to 

 permit accurate manipulation and weighing even when the 

 current density on the cathode is very considerable and variable 

 within wide limits. Other metals have been found to behave 

 similarly and the results of further experimentation w T ill be 

 described later. 



The advantages of this rotating cathode in analytical opera- 

 tions are obvious : the process as described is rapid, exact, and 

 very simple. The apparatus required, moreover, is inexpen- 

 sive, and, if it is desired to make many determinations simul- 

 taneously, a single motor may be made to drive a running belt 

 over any reasonable number of rotating shafts. 



Am. Jour. Sci.— Fourth Series, Yol. XV, No. 88. — April, 1903. 

 22 





Nickel 



Nickel 





taken. 



taken. 





grm. 



grm. 



1 



0-0954 



0-0954 



2 



0-0954 



0-0953 



3 



0-0954 



0-0956 



4 



0-0954 



0-0953 



5 



0-0954 



0-0955 



6 



0-1738 



0-1736 



1 



0-1738 



0-1740 



8 



0-1738 



0-1740 



9 



o-ms 



0-1737 







0-1738 



0-1738 



Current. 



ND 







amp. 



100. 



Time. 





1-5 



5 



30 



mi 



3 



10 



25 



(C 



3 



10 



25 



(I 



3-5 



11-7 



20 



a 



3-5 



11-7 



20 



a 



3-5 



11-7 



25 



a 



3-5 



11-7 



25 



u 



4 



13-3 



25 



a 



4 



13-3 



25 



a 



4 



13-3 



25 



a 



