169 
These results show that the sensitiveness of the test is not impaired by 
the presence of large amounts of cobalt. 
B. THe TscHuGArEv-TREADWELL MeEruHop. 
10 ce. portions of 0.0921 molar CoSO,, equivalent to 54.31 mg. Co., with 
varying small amounts of NiSO, were heated with ammonia until a clear 
solution was obtained, hydrogen peroxide added and the solutions heated 
till excess of peroxide and ammonia was removed, diluted to 50 ee., 1 ec. of 
dimethylglyoxime solution added and the time required for the red pre- 
cipitate to appear was observed. Results below. 
TABLE VI. 
NiSO,4 
Vol. Conc. molar Mg. Ni. Ratio Ni : Co. Results. 
LO GG Saco 0.0005 0.2934 1185 Red ppt. 1 hour. 
(2). OEE sce eae eee 0.0005 . 2641 1 : 206 Red ppt. 1 hour. 
{83 CED e csosd Eel Gree tee 0.0005 . 2347 i Sei Red ppc. 1 hour. 
Uf Och ae eee 0.0005 . 2052 1 : 264 Red ppt. 24 hours. 
OIC ass aah ack: = 0.0005 . 1760 1 : 309 Red ppt. 24 hours. 
RICO Meier oreta so ats 0.0005 . 1467 US S3740) Red ppt. 24 hours. 
BRCCH ins te thiol sada’: 0.0005 1172 1 : 462 Red ppt. 24 heurs. 
Taking the minimum amount of nickel that could be detected in 1 hour, 
0.2347 mg., we observed the effect of larger proportions of cobalt. The 
procedure and final volume were the same as in the experiments recorded 
In Table VI. 
TABLE VII. 
CoSO, 0.0921 molar Mg. Co Ratio Ni : CO Results. 
OTC Cera aah oni hentia shee ote 54.31 Tee2oit Red ppt. after 1 hr. 
MC Chris chara Rede Gna ee case 81.47 1 : 346 No ppt. after 1 hr. 
CIA) PEO Ae Re Non tae ea Pets te tee 108.62 1 : 462 No ppt. after 1 hr. 
CAST C Cale Oh ie inte cron MOET EEE eee 135.78 I SATE No ppt. after 1 hr. 
SOLCC Nera. not Shek bug ast ik eee oe 162.93 1 : 693 No ppt. after 1 hr. 
