ATOMIC WEIGHTS 431 



.8529 gTm. (C„H,N),Co,Cyio gave .1010 grm. Co. 11.842 per cent. 



.6112 " .0723 " 11.829 



.7140 " .0850 " 11.905 



.9420 " .1120 " 11.890 



Mean, 11.8665, ± .0124 



Hence Co = 59.04. 



Xext in order is the work clone by Lee ' in the laboratory of Wolcott 

 Gibbs. Like Weselsky^ Lee ignited certain cobalticyanides and also 

 nickel ocyanides in hydrogen and determined the residual metal. The 

 double cyanides chosen were those of strychnia and brucia, salts of very 

 high molecular weight, in which the percentages of metal are relatively 

 low. A series of experiments with purpureocobalt chloride was also 

 carried out. In order to avoid admixture of carbon in the metallic resi- 

 dues, the salts were first ignited in air, and then in oxygen. Eeduction 

 by hydrogen followed. The salts were in each case covered by a porous 

 septum of earthenware, through which the hydrogen diffused, and which 

 served to prevent the mechanical carrying away of solid particles ; further- 

 more, heat was applied from above. The results attained appeared to be 

 satisfactory, and assign to nickel and cobalt atomic weights varying from 

 each other by about a unit; Ni being nearly 58, and Co about 59, Avhen 

 = 16. The cobalt results agree remarkably well with those of Weselsky. 

 The following are the data obtained : 



Brucia niclelocyanide, NuCi/t^^{C ..^^Ho^N .,0 ^) JI r,.10HM . 



Salt. JSli. Per cent. Ni. 



.3966 .0227 5.724 



.5638 .0323 5.729 



.4000 .0230 5.750 



.3131 .01795 5.733 



.4412 .0252 5.712 



.4346 .0249 5.729 



Mean, 5.7295, ± .0034 

 Hence Ni = 58.027. 



Strychnia nick eJo cyanide, iVijCT/io (C*2iS"22iVoOo) siJ,;.<S'77oO. 

 Salt. 

 .5358 

 .5489 

 .3551 

 .4495 

 .2530 

 .1956 



.005 



Hence Ni = 58.085. 



Am. Journ. Sfi. (3), 2, 44. 1871. 



