io WlLDE, Points of Chemical Philosophy. 



transformation of higher members of different species 

 directly into each other. 



While it is universally admitted that elementary 

 substances and their combinations have structural arrange- 

 ments of their internal parts (static or stato-dynamic) 

 which distinguish the properties of the members of one 

 species from those of another, the discovery of the spon- 

 taneous transformation of radium combinations into 

 helium has clearly demonstrated that the " constitution of 

 matter " is not necessarily atomic, in the sense generally 

 accepted by chemists, and that the atoms of Newton and 

 Dalton are not the immutable entities which they postu- 

 lated them to be. It is, however, a profound error to 

 suppose that the lustre of Dalton's reputation is at all 

 diminished by the supersession of his atomistic philosophy, 

 and great injustice would be done to his memory by this 

 supposition. Dalton's abiding reputation rests upon his 

 discovery and experimental demonstration of the law of 

 chemical combination in definite and multiple proportions 

 (in units of hydrogen), through which the law of definite 

 and multiple proportions of the elements among them- 

 selves (with their consequent transformations) is the 

 orderly and natural development. 



The resolution of the radium-bromide emanation into 

 helium necessarily raises the question whether the distinc- 

 tion hitherto made between elementary substances and 

 their chemical combinations has a real foundation in 

 nature, or is only an arbitrary division arising from 

 ideas of composition derived from mechanical mixtures 

 used in the common arts of life, as set forth in connexion 

 with the following extract from my first paper on elemen- 

 tary substances 1 : — 



1 Proc. Manch. Lit. Phil. Soc, vol. 17, p. 194, and Memoirs, vol. 10, 

 pp. 123—4, 1887. 



