NICKEL AND COBALT. 301 



Cobalt. 



CoO. Co. Per cent. Co. 



6.3947 5-0284 78.634 

 6.6763 5.2501 78.638 

 5.6668 4.45 60 78.633 

 2.9977 2.3573 78.637 

 8.7446 6.8763 78-635 

 3.2625 2.5655 78.636 



6.3948 5.0282 78.630 

 8.2156 6.4606 78.638 

 9.4842 7.458o 78.636 

 9.9998 7.8630 78.632 



Mean, 78.635, .0002 



Shortly after the discovery of nickel carbonyl, NiC 4 O 4 , Mond, Langer, 

 and Quincke*made use of it with reference to the atomic weight of 

 nickel. The latter was purified by distillation as nickel carbonyl, then 

 converted into oxide, and that was reduced by hydrogen in the usual 

 way. 



NiO. Ni. Per cent. Ni. 



.2414 .1896 78.542 



.3186 .2503 78.562 



.3391 .2663 78.531 



Mean, 78.545, .0061 



Schutzenberger's experiments,t published in 1892, were also few in 

 number. First, nickel sulphate, dehydrated at 440, was calcined to 

 oxide. 



3.505 grm. NiSO 4 gave 1.690 NiO. 48.217 per cent. 



26008 " 1.2561 " 48.297 " 



Mean, 48.257, .027 



Second, nickel oxide was reduced in hydrogen, as follows : 



1.6865 grm. NiO gave 1.3245 Ni. 78.535 per cent. 



1.2527 " .9838 " 78.533 " 



Mean, 78.534 



Iii one experiment with cobalt oxide, 3.491 grm. gave 2.757 Co, or 

 78.975 per cent. In view of the many determinations of this ratio by 

 other observers, this single estimation may be neglected. The experi- 

 ments on nickel sulphate, however, should be combined with those of 

 Marignac and Baubigny, giving the latter equal weight with Schutzen- 

 berger's, thus : 



*Journ. Chem. Soc., 57, 753. 1890. 

 tConipt. Rend., 114, 1149. 1892. 



