IRON, COBALT, iAND NICKEL 355 



carbonate and the precipitated " carbonates are heated ; the suboxides 

 are thus obtained, and these latter are reduced' In a stream ofi 

 hydrogen, or even by heating with ammonium chloride. They easily 

 oxidise when in the state of powder. When the chlorides of nickel 

 and cobalt are heated in a stream of hydrogen, the metal is deposited 

 In brilliant scales. Nickel is~ always much more easily and quickly 

 reduced than cobalt. Nickel melts more easily than cobalt, and this 

 even furnishes a means of testing the heating powers of a reverberatory 

 furnace. Cobalt fuses at a temperature only a little lower than that 

 at which iron does. In general, cobalt is nearer to iron than nickel, 

 nickel being nearer to copper. 32 . tli3 Both nickel and cobalt have mag- 

 netic properties like iron, but Co is less magnetic than Fe, and Ni stiU 

 less so. The specific gravity of nickel reduced by hydrogen is 9'1 and' 

 that of cobalt 8-9. Fused .cobalt has -a specific gravity of 8-5, the 

 density of ordinary nickel being almost the same. Nickel has ,a greyish, 

 silvery-white colour ; it is brilliant and very ductile, so that the finest 

 wire may be easily drawn from it. This wire has a resistance to 

 tension equal to iron wire. The beautiful colour of nickel, and the 

 high polish which it is capable of receiving and retaining, as it does 

 not oxidise, render it a useful metal for many purposes, and in 

 many ways it resembles silver. 32 trf It is now very common to cover 



33t>i All we know respecting the relations of Co and Ni to 'Fe and Cu confirms the 

 fact that Co is more closely related to Pe and Ni to Cu ; and as the atomic weight of 

 Fe =* 56 and of Cu = 68, then according to the principles of the periodic system it would 

 be expected that the atomic weight of Co would be about-59H50, whilst that of Ni should 

 be greater than that of Co but less than that of Cu, i.e. about. 50;5-.60-5. Hpwever, aft 

 yet the majority of the determination)* of the atomic -weights ,bf Co and Ni give a 

 different result and show that a lower atomic weight is obtained for Ni than for Co. 

 Thus K. Winkler (1894) obtained (etnploying metals deposited electrolytically and deter- 

 mining the amount of iodine which combined with them) Ni = 68'72 and Co = 59'87 (if 

 H = 1 and I <= 126'53). In my opinion this should not be regarded as proving that the 

 principles of the periodic system cannot be applied in this instance, nor as a reason for 

 altering the position of these elements in the'system (i.e. by placing Ni after Fe, and Co 

 next to Cu), because in the first place .the figures given by different chemists (for instance, 

 Zimmerinann, Kriiss, and others) are somewhat divergent, and in the second place the 

 majority of the latest modes of determining the 'atomic weights of Co and Ni aim at 

 finding what weights of these metals react witjh known weights of other elements without 

 taking into account the faculty they have of absorbing hydrogen; since this faculty is 

 triore developed hi Ni than in Co the hydrogen (occluded in Ni) should lower the atomio 

 'weight of Ni more than that of Co. On the whole, the question of the atomio 

 weights of Co and Ni cannot yet be considered as. .decided, notwithstanding the 

 numerous researches which have been made ; still there can be no doubt that the atomio 

 weights of these two metals are very nearly equal, and greater than that of Fe, but les 

 than that of Cu. This question is of great interest, not only for completing our know- 

 ledge of these metals, but also for perfecting our knowledge of the periodic system'of the 

 Elements. 



6tri p or stance, the alkalis may be fused in nickel vessels as well as in silvefj 

 because they have no action upon either metal. Nickel, like silver, is not acted upon b$ 



