600 SCIENCE PROGRESS 



matched in the case of carbon compounds is that noticeable, 

 for example, between the elements oxygen and tellurium, the 

 one being entirely non-metallic in its behaviour, whilst the 

 latter simulates a metal and is therefore often classed as a 

 metalloid. But these two elements are clearly members of a 

 family and it is to be supposed that they are genetically 

 related ; if so, there must be some factor which conditions 

 metallicity and this factor apparently tends to come into 

 operation more and more as the " atomic weight " increases 

 in the case of the elements. 



It appears to me that a legitimate provisional explanation 

 of the wonders of radium is to be found in the as yet un- 

 recognisable wondrous properties of helium — not of helium as 

 we know it but of atomic helium or helium-stuff. 



The hypothesis which I ventured to suggest when the 

 discovery of argon was brought under the notice of the 

 Royal Society, in 1895, has gained in probability since the 

 discovery has been made that the allied element helium is 

 a product of the degradation of radium. If, as I not only 

 think possible but now believe to be the case, the atoms of 

 helium and of the allied inert gases are gifted with intense 

 activity, far beyond anything we know of, it may well be 

 that when such atoms enter into combination, either with 

 one another or with other elements, the amount of energy 

 set free is very great 1 and that when they combine with 

 other materials they produce changes in properties very 

 different from and far more profound than those we know 

 of at present. 



That my hypothesis is not an impossible one even 

 physicists will admit, I think; at all events, I may claim the 

 support of Professor Rutherford, as expressed in a paragraph 

 in the address he delivered in Winnipeg about two years ago : 



" Since in a large number of cases the transformations of 

 the atoms are accompanied by the expulsion of one or more 

 charged atoms of helium, it is difficult to avoid the con- 



1 Sir George Darwin, in the recent edition of his book on The Tides, 

 speaking of radio-activity, remarks : " We have recently learned that atoms 

 may in themselves possess a colossal store of energy which is quite distinct 

 from that of chemical affinity .'' It is clear from such a statement how little 

 the position is understood. There is nothing to show that the energy developed 

 by the decomposition of radium is not that of chemical affinity. 



