NO. II STRUCTURE OF THE ATOM PARSON 75 



1. For the paramagnetism of a metallic atom we have the follow- 

 ing relations : 



Salts in solution >Hydrated salts > Anhydrous salts > Free metal. 



This is true for V, Cr, or Mn. In the case of ferromagnetic metals, 

 the last step in the series does not hold, of course, except above the 

 Curie point. These relations have not been established with any 

 great completeness, and possibly some exceptions exist. 



2. In mixtures of liquid Oxygen and Nitrogen, the molecular 

 susceptibility of the Oxygen becomes greater as its concentration 

 becomes less (K. Onnes). 



3. Contrary to Curie's law, almost half of the paramagnetic ele- 

 ments become increasingly paramagnetic as the temperature rises 

 (H). This can only be due to increased freedom acquired by the 

 magnetons that are responsible for the forces between atoms, as 

 explained in §19. 



4. Most of the diamagnetic solid elements (e. g., Bi, Sb, Pb, Tl, Te, 

 In, Cu) become less diamagnetic as the temperature is raised (H), 

 the change being in some cases especially marked at the melting point, 

 after which a further rise in temperature does not usually alter the 

 magnetic properties. Evidently we have here cases of complex mole- 

 cules which become less stable as the melting point is approached, and 

 which at that point are suddenly broken down into the atoms or 

 molecules that are stable in the liquid phase. From the magneton 

 theory we should expect this process to be accompanied by the 

 magnetic changes that are observed. Those elements which do not 

 show this effect are for the most part elements of lower atomic 

 weight which are known to give stable complex molecules persisting 

 in the liquid and even in the gaseous state (e. g., P, As, S, Se) : 

 these, therefore, act more like the substances described under the 

 next heading (5). A very striking example of the effect of fusion is 

 given by the alloy FeZn 10 ; when solid this is non-magnetic, when 

 liquid it is very strongly magnetic : a comparison of the suscepti- 

 bility of this alloy with that of the Iron atom in salts would be of 

 great interest, but appears not to have been made. An example of the 

 effect of dissociation by dilution is given by solutions of Bismuth in 

 mercury, which when very dilute are less diamagnetic than pure mer- 

 cury: this must be due to the dissociation of the complex Bi mole- 

 cules. There are, however, a few exceptions to this general rule. Ag 

 and I become more diamagnetic as the temperature rises (H). 

 Crystalline Tin is slightly paramagnetic, liquid Tin is diamagnetic ; 

 but here we have grey Tin, which is still more diamagnetic. 



