398 Scientific Intelligence. 



tions of the radio-active elements, but Dr. Jones brings forward 

 the argument that radium is not formed directly from radium, and 

 favors the view that the production of radium is a product of 

 synthesis, not of mere decomposition. The question can be 

 finally settled only after a considerable amount of pure radium 

 material is available, and some time must elapse before this is 

 realized. — Amer. Chem. Jour., xxxiv, 467. i-i. t.. w. 



5. Mechanical Separation of Organic Substances. — Bordas 

 and Touplaw have applied a novel method for the detection of 

 adulterations and impurities in chocolate, which will probably be 

 applicable in other cases. The insoluble matter freed from fat 

 was treated with liquids of increasing densities, from 1*340 to 

 l - 600, made by mixing carbon tetrachloride and benzine, in such 

 a manner that successive portions were caused to float when 

 whirled in centrifugal tubes. The different ingredients were 

 thus readily distinguished by their colors, they could be collected 

 upon filters and weighed, and then be subjected to microscopic 

 examination. Oil-cake, germs, shells, potato-starch, and mineral- 

 matters were thus easily separated in the case of chocolate. — 



Compter JRendus, cxlii, 639. h. l. w. 



6. Constitution of the Electron. — W. Kaupmann, whose exper- 

 imental proof that the mass of the electron increases with its 

 velocit} 7 , and that this' mass is probably largely electrical, has 

 been prompted by late theoretical discussions to repeat his work 

 with a view of determining which theory best explains the exper- 

 imental results. The theories he takes are those of Abraham, 

 Lorentz and Bucherer. The theory of Abraham may be called 

 the theory of the rigid electron, in which the field of the electron 

 extends outwaixlly to infinity and within to the surface of a 

 sphere of constant radius a ; and the Maxwellian equations 

 relating to a solid sphere with surface or volume charge in space 

 are employed. H. A. Lorentz assumes (Yersl. Kon. Akad. 

 Wett. Amsterdam, 27 May 1904) that the dimensions of all 

 bodies, including the molecules and the electrons, change their 

 dimensions with velocity ; and that mechanical mass changes 

 in the same or analogous way as that of the electron. Bucherer 

 supposes that the electron undergoes a deformation, keeping a 

 constant volume. He makes use of the so-called " Heavyside 

 ellipsoid," and can translate his theoretical results into those of 

 Lorentz by this theory of deformation. 



Kaufmann employs in his experiments a crystal of radium 

 bromide, submitting its /3-radiations to both electrical and mag- 

 netic fields ; and carries out the research with remarkable skill. 

 His entire apparaus can be clasped in a man's hand, and the 

 almost microscopic details are carried to great perfection. He 

 arrives at the result that Abraham and Bucherer's theories agree 

 better with the experimental results than that of Lorentz. The 

 ratio of charge to mass deduced from the various theories are as 

 follows : 



