480 



On the Relationship of the Magnetic Metals. 



with the former metals chemically, they are physically charac- 

 terized by their extraordinary tenacity and difficult fusibility. 

 Manganese has lately been used to replace nickel in the alloy of 

 German silver, and with excellent results I am informed. It is 

 also worthy of note that the compounds of these five metals are 

 conspicuous by the brilliancy of their colours, all their salts ex- 

 erting a selective absorption on light, and their oxides dissolved 

 in borax yielding well-known and characteristic tints — a com- 

 paratively rare feature outside this group. 



Further, it is well known that the ores of cobalt and nickel are 

 almost invariably found associated in the earth and with difficulty 

 separated. It is also noteworthy that both nickel and cobalt 

 are usually present in meteoric iron — the average composition of 

 meteorites being 90 per cent, of iron, 8 per cent, of nickel, and 

 0*5 per cent, of cobalt, curiously enough often with a trace of the 

 other feebly magnetic metals, manganese and chromium. 



This uniform coincidence in the properties of iron, nickel, and 

 cobalt, suggests the practical inference that nickel and cobalt 

 might be obtained in a malleable and ductile condition when sub- 

 mitted to a process similar to that by which wrought iron is pro- 

 duced. At present it is impossible to procure nickel or cobalt 

 wire, though there seems no reason why they could not be made 

 if a demand arose. Nickel wire would probably prove very useful 

 from its high tenacity and comparative freedom from oxidation. 



The following Table sums up some of the most striking points 

 of contact in the physical properties of the three magnetic metals 

 par excellence. 



Table showing the Physical Relationship of the Magnetic 

 Metals. 



Sub- 

 stance. 



Den- 

 sity. 

 Water 

 =1. 



Atomic 

 weight. 

 H=l. 



Specific 

 heat. 



Water 

 = 1. 



Atomic 

 heat. 



Dilatation 



Conductivity 



Tenacity 

 and melt- 

 ing-point. 



by 

 heat*. 



by 



strain*. 



for heat. 

 Silver =1. 



for sound*. 

 Air=l. 



Iron ... 

 Nickel . 

 Cobalt. 



7-8 

 8-3 

 8-5 



560 

 58-5 

 58-5 



01138 

 01091 

 0-1070 



6-38 

 6-33 

 6-26 



•0926 

 •0899 

 •0981 



•0387 

 •0394 

 •0436 



•168 

 131 

 172 



15-3 

 14-9 

 14-2 



Very high. 

 >> 

 » 



From this Table it is evident that the molecular constitution 

 of the magnetic metals is essentially alike, largely differing from 

 bodies which are not magnetic. And this being so, further evi- 

 dence is afforded that the evolution of ordinary magnetic pheno- 

 mena is in some way associated with the peculiar and similar 

 structure of the molecules of iron, nickel, and cobalt. 



* For the figures in this column I am indebted to a paper by M. A. 

 Masson, in the Annates de Chimie et de Physique for 1858. In the heat 

 column the decimal would, of course, have to be moved four places to the 

 left to express the coefficient for 1° C. The dilatation by strain was of 

 one metre of the body under a weight equal to itself. 



