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THE EVOLUTION OF THE ELEMENTS. 
By M. M. PATTISON MUIR, M.A. 
T HE paper which Mr. Lockyer recently read before the 
Royal Society suggests many interesting problems to the 
chemist, but at the same time it awakens within him a feeling 
bordering upon despair. Are we not to be allowed to retain our 
belief that the elements are indeed what their name claims them 
to be ? If we allow the physicist to take our elements from us, 
what possession of ours can we deem secure from his attack ? 
But, whatever be the result, we must examine the facts, and 
endeavour to arrive at a just conclusion concerning the nature 
of the so-called elementary bodies. 
It has long been known that the elements may be arranged 
in certain families or groups, between the members of each of 
which many remarkable relationships are apparent. Not un- 
frequently, the numbers expressing the relative amounts of 
different elements, being members of the same group, which 
combine together in the formation of compounds, are found to 
bear certain simple relations to one another. Thus in the 
family of the halogens the combining weight of bromine is 
expressed by a number which is almost exactly the mean of the 
combining weights of chlorine and iodine. 
Reasoning on such facts as this, Prout, many years ago, 
propounded the hypothesis that the elements are all compounds 
of one kind of matter; that is, that the smallest particles of 
each element which exhibit the characteristic properties of the 
element are composed of varying quantities of one and the same 
primary form of matter. This primary form of matter Prout 
supposed to be hydrogen. This hypothesis required that 
the weights of the smallest individual particles of each 
element should be whole multiples of that of the smallest in- 
dividual particles of hydrogen. But exact investigation, more 
especially the investigations of Stas, showed that this was not 
the case. Stas obtained fractional numbers expressive of the 
combining weights of those elements which he investigated. It is, 
however, worthy of remark that the most recent researches of Dumas 
have shown that Stas overlooked a source of error in his other- 
