124 CONCEPTION OF THE CHEMICAL ELEMENT 



not further changing, we have only negative evidence 

 to go on. This branching is very important as 

 showing how from one element two products or more 

 in very different quantity may result, and may be 

 the explanation of the excessive rarity of certain of 

 the elements in nature. 



HISTORY OF THE ANALYSIS OF MATTER. 



The second, and in many respects even more 

 revolutionary phase in the development of the study 

 of radioactive change arose out of the chemical 

 characterisation of the successive products, but some 

 historical comment on the various influences which 

 have gone to shape the current conception of the 

 chemical element may be of interest before dealing 

 with this development. 



The analysis of matter into different chemical 

 elements was at first concerned with known materials 

 obtainable in abundance. The question, then, was 

 not as to the existence or otherwise of certain 

 elements, but whether certain thoroughly well-known 

 substances were elements or compounds. Boyle's 

 original celebrated definition was a purely practical 

 one. That was to be regarded as elementary which 

 could not by any means be separated into different 

 substances. Almost at once, however, there crept 

 into the interpretation of this conception two fallacies, 

 or two aspects of the same fallacy, implicit in all 

 the later characterisations of the elements, right up 

 to the present time, namely, first, that chemical 

 analysis was necessarily the most fundamental and 

 searching kind of material analysis, known or to be 

 discovered, and, secondly, that chemical compounds 

 were necessarily more difficult to resolve than simple 

 mixtures. Any means soon came to mean any 

 chemical means, and the element, in consequence, 



