168 
A. Tue Sitver METHOD. 
Definite volumes of solutions of NiSO,; and CoSO, of known concentration 
were measured from burets into a casserole, KCN added until the precipitate 
just dissolved, and the solution heated and rotated until complete oxidation 
was effected. The solution was then diluted with water at 85° to 50 ee., 
1 ce. of dimethylglyoxime solution added, and then AgNO; dropwise with 
vigorous stirring until a permanent precipitate was produced. The time 
required for the pink color of nickel glyoximine to appear was observed. 
In cases where the time exceeded one hour, observations were made at the 
end of 24 hours. The results are given below. 
TABLE IV. 
In each expt. 10 cc. CoSO; 0.0921 molar, equivalent to 54.31 mg. Co, was used. 
——— a ~ - = 
NiSO, 
Ratio Ratio 
Vol. Cone.molar| Meg. Ni. Ni : Co. Ni: H20 Results. 
| 
2 ECs e- 0.0005 0.0587 | 1: 925 1 852,000 | Ppt. pink immediate. 
A BCG 0.0005 0440 1 : 1234 1: 1,140,000 | Ppt. pink 4 min. 
LJ Olce: 0.0005 .0293) | 121851 1 :1,707,000 | Ppt. pink 6 min. 
4 75(CCk ee 0001 .0264 1 : 2054 1: 1,894,000 | Ppt. pink 10 min. 
A OCC ae .0001 .0235 1. 3. 2314 Ppt. pink 20 min. 
Sh Os oie .0001 .0205 | 1 : 2644 1: 2,440,000 | Ppt. pink 30 min. 
SaO ec... o4 0001 .0176 | 1: 3085 Ppt. pink 24 hours. 
BES CRie | 0001 | 9137 L 2 3702 1 : 3,650,000 | Ppt. pink 24 hours. 
Taking the minimum amount of nickel that could be detected in cobalt 
in 30 minutes, 0.0205 mg., we observed the effect of larger proportions of 
cobalt. The procedure and final total volume of solution were the same as 
in the preceding experiments. 
TABLE V. 
CoSO. 0.0921 molar Meg. Co. Ratio Ni : Co Results. 
EEC ren h ava ete cate ate ets Siew (eis re 81.47 1 : 3966 Ppt. pink 30 min. 
DORGG= fae ney aie ek. bistwcs weteiaee 2 108.62 | 1 : 5288 Ppt. pink 30 min. 
TEC RON. opan RETO cts cae rere fete aks 135.78 1 : 6610 Ppt. pink 30 min. 
=f Oe  ehhets| Wis A Ne ee 162.93 | aWrear hey Ppt. pink 30 min. 
