590 SCIENCE PROGRESS 



As compounds of argon and its companions in air — let me 

 call them the Argonides — are unknown, we can only determine 

 the molecular weights of these elements, not their atomic 

 weights. Ramsay contends that the argonides are all monatomic 

 elements — that their molecules consist of single atoms ; i.e. that 

 the atomic weight is identical with the molecular weight. He 

 bases this conclusion on the relatively low molecular heat 

 capacity of these gases at constant volume. I took exception 

 to the argument when Rayleigh and Ramsay brought their 

 discovery of argon before the Royal Society in 1895, 1 pointing 

 out that however much it might be held to favour such doctrine, 

 it in no way sufficed to justify the acceptance of the view. But 

 apparently chemists do not think for themselves in these days 

 any more than ordinary folk do : the conclusion is now almost 

 universally accepted that the argonides are monatomic elements. 



My attitude with regard to this question is that of the Hon. 

 Robert Boyle in the Sceptical Chemist: 



" 1 blush not to acknowledge that I much less scruple to 

 confess that I doubt when I do so than to profess that I know 

 what I do not : and I should have much stronger expectations 

 than I dare yet entertain to see philosophy solidly established, 

 if men would more carefully distinguish those things that they 

 know from those that they ignore or do but think and then 

 explicate clearly the things they conceive they understand, 

 acknowledge ingenuously what it is they ignore and profess 

 so candidly their doubts, that the industry of intelligent persons 

 might be set on work to make further inquiries and the easiness 

 of less discerning men might not be imposed on." 



The question I raise is one of fundamental importance but 

 a difficult one to argue. 



To my way of thinking, an inert element is a contradiction 

 in terms — but in saying this I am merely giving expression to 

 my personal sentiment. 



A difficulty that is more generally felt is that of classifying 

 the argonides in any satisfactory manner. Since the introduc- 

 tion of MendeleefFs Periodic System of Classification, chemists 

 have always recognised that the properties of the elements 

 rise and fall in periods — it has long been clear, however, that 

 it is impossible to order elements simply in accordance with 

 their atomic weights. The system we are gradually being led 



1 Chemical News, vol. lxxi. p. 61. 



