350 Prof. J. Traube on the 



are eliminated and the elements compared in their gaseous 

 state*; I have further shown that f to the changes in the pro- 

 perties which an element undergoes as it passes from the elementary 

 state to that of a definite class of compound, there correspond 

 throughout simultaneous volume changes. All these facts, 

 combined with the well-known defects of the periodic systems, 

 have led me to enunciate the proposition — The properties of 

 the elements and their compounds are primarily functions of 

 the atomic and molecular volumes. A satisfactory systematic 

 presentation must primarily be based on the relations con- 

 necting the volumes (and possibly also the shapes) of the atoms. 



The fact that, according to the well-known volume curve of 

 Lothar Meyer, the atomic volumes are periodic functions 

 of the atomic weight, and that thereby all other properties 

 become functions of a function, is best interpreted as follows : 



When the elements are arranged according to their atomic 

 weights, there are frequently found at periodic intervals elements 

 whose atomic volumes and atomic shapes stand in simple nume- 

 rical relationship ; only wJien such is the case are the elements 

 also related to each other in their remaining properties. 



The periodic interval is thus by no means the essential 

 determining factor ; the determining factors are volume and 

 shape of atom. 



I would particularly draw attention to the fact that these 

 views of mine regarding the periodic system are in excellent 

 agreement with those of J. J. Thomson J regarding the 

 structure of atoms — views which, though hypothetical, are 

 strikingly original and worthy of all attention. J. J. Thomson 

 shows, by building up the atoms out of negatively charged 

 corpuscles, that at definite periodic intervals there recur 

 atoms of similar constitution, and hence also similar space 

 relations, and that it is these forms of matter whose properties 

 are related. It seems to me very remarkable that the views 

 which I have for a long time advocated solely on the ground of 

 my studies of volume-relations, should have been arrived at in 

 a totally different way by so competent an authority, on the basis 

 of the electron theory. 



I now wish to return to the investigations of Mr. Richards, 

 and say a few words about them. 



Starting from the compressibility of matter and the con- 

 traction of the atoms, Richards arrives, although considerably 



* L. c. p. 375. 



t " Raum der Atome," F. W. Ahrens Samml. Chem. und Chem.-Techn. 

 Vortr. p. 14. 



X J. J. Thomson, Phil. Mag. [6] vol. vii. p. 237 (1904) ; also < Electricity 

 and Matter.' 



