Chemistry and Physics. 387 



magnetic field and are absorbed by gases and thin layers of metal. 

 These rays differ from one another in penetrating power. The 

 emanations from thorium and radium differ greatly in their rates 

 of decay of radiating power. The presence of emanations gives 

 rise to a complicated phenomenon of " excited " radioactivity. 

 Elster and Geitel have recently shown that a negatively charged 

 wire in the open air, free from all possible contamination of radio- 

 active substances, becomes strongly radioactive. This activity 

 decays at a different rate from that due to thorium and radium 

 and is of greater penetrating power. — Phil. Mag., No. 19, July, 

 1902, pp. 1-23. J. T. 



13. Induced Radioactivity in Air. — It has been shown by Elster 

 and Geitel that a strongly electrified wire becomes after several 

 hours strongly radioactive. The authors conclude that the atmos- 

 phere contains some radioactive substance which is attracted to 

 the wire, and that this emanation is like that from thorium. 

 Professor J. J. Thomson, however, comes to the conclusion that 

 it is not necessary to make this assumption and believes that 

 negatively electrified surfaces may become radioactive w^ithout 

 the deposition upon them of substances possessing radioactive 

 properties. He found that a negatively electrified wire placed in 

 a closed vessel, the enclosed air or gas being exposed to Rontgen 

 rays, became radioactive. When the enclosed gas had been 

 bubbled through air the effect was very large. Professor Thom- 

 son thinks that the ionizing power of the wire may be due to a 

 kind of polarization which produces an electric field which makes 

 the wire into a cathode emitting cathode rays of feeble penetrat- 

 ing power, which ionize the gas in the neighborhood of the wire. 

 — Phil. Mag., No. 21, 1902, pp. 352-367. J. t. 



14. PeviablePays of Radioactive Substances. — Professor Ruth- 

 erford and Mr. Grier have discovered that uranium, thorium 

 and radium all emit both deviable and non-deviable rays. They 

 differ from polonium, which does not emit deviable rays. Uranium 

 gives out more deviable rays than radium or thorium. The authors 

 believe that most of the deviable rays are given out by a second- 

 ary product, produced by a disintegration of the uranium or 

 thorium atom or molecule. These secondary products differ from 

 the uranium or thorium in chemical properties. — Phil. 3Iag., No. 

 21, Sept., 1902, pp. 315-330. j. t. 



15. Removal of Negative Electricity from the air by falling 

 drops of water. — A. Schmatiss shows that there is a possibility 

 that each rain drop passing through higher layers of air rich in 

 ions draws with it negative ions and conveys them to the earth. 



— Ann. der Physik, No. 9, 1902, pp. 224-237. J. t. ^ 



16. The Elements of Exjoerimental Phonetics ; by Edward 1/ 

 Wheeler Scripture. Pp. xvi + 62T. Charles Scribner's Sons. 

 Yale Bicentennial Publications. — Valuable contributions have 

 been made by Professor Scripture to the analysis of speech 

 sounds by means of his ingenious apparatus for enlarging and 

 tracing the curves recorded by the graphophone, and his experi- 



