144 Life and Matter [chap.vih. 



existence ; and a fresh act of magnetisation 

 can recall it, or something indistinguishable 

 from it, into manifest activity again ; so 

 that it, or its equivalent, can once more 

 interact with the rest of material energies, 

 and be dealt with by physicists, or subserve 

 the uses of humanity. Until that time of 

 re-appearance its existence can only be 

 inferred by the thought of the mathe- 

 matician : it is indeed a matter of theory, 

 not necessarily recognised as true by the 

 practical man. 



Our present view is that the act of 

 magnetisation consists in a re-arrangement 

 and co-ordination of previously existing 

 magnetic elements, lying dormant, so to 

 speak, in iron and other magnetic materials ; 

 only a very small fraction of the whole 

 number being usually brought into activity 

 at any one time, and not necessarily always 

 the same actual set. Only a small and in- 

 discriminate selection is made from all the 

 molecular loops ; and it can be a different 

 group each time, or some elements may be 



