322 Gooch and Medw ay —Rotating Cathode in the 



Table A. 



1 



Copper 



taken. 



grm. 



0-0051 



Copper 



found. 



grm. 



0-0652 



Error. 



grm. 



+ 0*0001 



Current, 

 amp. 

 0-8 



ND 

 100. 

 2-7 



Time. 

 25 min 



2 



0-0651 



0-0652 



+ 0-0001 



0-8 



2-7 



15 



a 



3 



0-0651 



0-0651 



o-oooo 



1 



3-3 



10 



« 



4 



00651 



0-0649 



— 0-0002 



1 



3-3 



10 



a 



5 



0-0651 



0-0658 



— 0-0003 



1 



3-3 



10 



a 



6 



0-1272 



0-1272 



0-0000 



2-5 



8-3 



15 



a 



7 



0-1272 



0-1271 



— 0-0001 



2-5 



8-3 



15 



a 



8 



0-i272 



0-1271 



—o-oooi 



2-5 



8-3 



15 



a 



9 



0-1272 



0-1270 



— 0-0002 



3 



10 



13 



a 



10 



0-1272 



0-1268 



— 0-0004 



3 



10 



12 



a 



11 



0-2548 



0-2548 



o-oooo 



3 



10 



20 



a 



12 



0*2548 



0-2548 



o-oooo 



4 



13-3 



20 



u 



13 



0-2548 



0-2550 



+ 0-0002 



4 



13-3 



20 



a 



14 



0-2548 



0-2546 



— 0-0002 



4 



13-3 



15 



a 



15 



0-2548 



0-2545 



— 0-0003 



4 



13-3 



15 



a 



That the copper can be completely deposited, though more 

 slowly, from a solution acidulated with nitric acid, is shown in 

 the following tables. In the experiments of Table E the solu- 

 tion contained 6 drops of dilute [1 : 4] nitric acid, and in those 

 of Table C 9 drops. 



Table B. 



Copper 



Copper 











taken. 



foard. 



Error. 



Current. 



ND 





grm. 



grm. 



grm. 



amp. 



100. 



Time. 



0-0651 



00648 



— 0-0003 



1 



3-3 



35 min. 



0-0651 



0-0652 



+ 0-0001 



0-8 



2-7 



30 " 



0-0651 



0-0650 



—o-oooi 



0-8 



2-7 



. 25 " 



0-0651 



0-0649 



— 0-0002 



1 



3-3 



25 " 



0-0651 



0-0650 



—o-oooi 



0-8 



2-7 



25 " 







Table C. 







Copper 



Copper 











. taken. 



found. 



Error. 



Current. 



ND 





grm. 



grm. 



grm. 



amp. 



100. 



Time. 



0-0651 



0-0652 



+ 0-0001 



1 



3-3 



35 mill. 



0-0651 



0-0648 



— 0-0003 



1 



3-3 



30 " 



0-0651 



0-0650 



—o-oooi 



1-5 



5 



25 " 



0-0651 



0-0650 



— o-oooi 



1-5 



5 



25 . " 



0-0651 



0-0647 



— 0-0004 



1*8 



6 



20 " 



The rapid deposition of silver was next tried. . To a 50 cm3 

 solution of AgN0 3 was added enough potassium cyanide to 

 dissolve the AgCN first formed. Three cm 3 of dilute sulphuric 

 acid w r ere run in and enough ammonia to make the solution 

 strongly alkaline. The method of manipulation was exactly 

 the same as in the case of copper. 



The following table records the determinations made with 

 a solution of silver nitrate standardized as the chloride. 



