340 Prof. J. Traube on the 



which lies on the circumference is proportional to the square 

 root of the whole. Under such circumstances an a particle, 

 if it struck the atom anywhere except at the edge, would pass 

 through without result. 



Since the energy required to make a pair of ions is 

 probably the same no matter what the atom or molecule may 

 be in which they are made, and no matter whether it be 

 solitary or a constituent of a complex molecule, we seem 

 driven to the belief that ionization consists in breaking bonds 

 which are always the same, both in character and in strength. 

 The electron is torn from its union with something else which 

 is always the same, and must form some constituent of all 

 atoms. This hypothesis also makes reasonable the supposition 

 that an act of ionization may be performed within a complex 

 molecule, and yet no conductivity be imparted to the gas. 

 For the act would then consist in the breaking of an electron 

 from its attachment to this common constituent, and would 

 not of necessity imply separation from the system of the 

 molecule. The idea of a common constituent is, of course, 

 an old one. It is certainly strengthened by the discovery 

 that radium and its successive products emit a particles which 

 are exactly alike. 



We wish to express our gratitude to Mr. J. P. Y. Madsen, 

 B.Sc, for the generous assistance which he gave us during 

 several weeks of full work, and to Professor Rennie, D.Sc, 

 and Mr. A. J. Higgin for their kindness in making the 

 chemical preparations. 



XL. On the Space occupied by Atoms: The Theories of 

 Th. W. Richards and J. Traube. By Prof. Dr. J. Teaube, 

 Berlin *. 



FOR several years f I have been busy with investigations 

 regarding the space relations of different forms of 

 matter, and have repeatedly pointed out the extraordinary 

 importance of this much neglected domain of science. 



To my satisfaction, so distinguished an investigator as 

 Th. W. Richards has recently} taken up the same problem, 



* Communicated by the Author. 



f See, especially, my latest work, Drude's Ann. d. Phys. Bd. v. p. 548 

 (1901), and Bd. viii. p. 267 (1902); further, the account in the 

 Boltzmann-Festschrift, p. 430 (1904) ; also Zeitschr. f. anorg. Chem. 

 Bd. xxxiv. p. 413 (1903), Bd. xxxviii. p. 399 (1904), Bd. xl. p. 372 

 (1904); and the older account: " Ueber den Baum der Atome, F. W. 

 Ahrens, Samml. chem, teclin. Vortrage, Bd. iv. p. 1 (1899), and my 

 Grundriss der Physikal. Chemie (Enke, Stuttgart, 1904). 



\ Th. W. Richards, Zeitschr. f. Physik. Chem, Bd. xl. pp. 169 & 602 

 (1902) ; Bd. xlii. p. 129 (1903) ; and Bd. xlix. pp. 1 & 15 (1904). 



