Chemistry and Physics. 319 



statement and finds that the human body cannot bear any greater 

 currents at high frequency than at low frequency. — Ann. der 

 Physik, No. 2, 1902, pp. 369-380. J. T. 



11. Distribution of Electric Current on Electrodes in rarefied 

 Media. — It is noticed that luminous areas appear on the metallic 

 terminals of Geissler tubes which are dependent on the electro- 

 motive force employed. A. Wehnelt has studied the connec- 

 tion between the distribution of these areas and the current 

 developed in the tubes, and arrives at the conclusions that 

 when the luminosity does not cover the entire terminal, the 

 current flows only through the part covered by the luminosity ; 

 the source of the cathode stream is coincident with the spot of 

 light on the cathode. He investigated the relations between the 

 areas of luminosity in different forms of electrodes and found 

 that the stream density is the same in every case between the 

 limiting surface of the luminosity and the dark cathode space. — 

 Ann. der Physik, No. 2, 1902, pp. 237-255. j. t. 



12. The Stratifications of Hydrogen. — Sir William Ceookes 

 gives the details of his attempt to prepare pure hydrogen. He gives 

 his reasons for believing that the blue components of the blue 

 and pink strata in the stratifications produced by the discharge 

 of electricity through rarefied hydrogen are due to a trace of 

 mercury. Occasionally, when no mercury vapor was present a 

 blue tint was observed which was traced to the phosphorus pen- 

 toxide tubes. The paper concludes with theoretical conclusions 

 in regard to the causes of stratification based on the electron 

 theory.— Nature, Feb. 20, 1902. j. t. 



13. Magnetic Declination Chart for the United States in 1902. 

 — The U. S. Coast and Geodetic Survey, O. H. Tittmann, Super- 

 intendent, has recently issued a chart of the United States, 

 giving the curves of equal magnetic declination and also those 

 of equal annual change for January 1st, 1902. The second series 

 of curves, which has not always been plotted out as here, adds 

 much to the interest of the chart. 



14. Die Fortschritte der Physik im Jahre 1902. Halbmonat- 

 liches Litter atur-verzeichniss / redigirt von Kael Scheel (reine 

 Physik) und Richd. Assmann (kosmische Physik). Braunschweig, 

 1902 (Fr. Vieweg und Sohn). — The Deutsche Physikalische Gesell- . 

 schaft has undertaken the publication of a semi-monthly cata- 

 logue giving the titles of all papers published in the various 

 departments of physics. These are given under the author's 

 name with title in the original language and are classified into 

 groups according to subject. Five numbers of the series (pp. 

 1-115) have been received, the last bearing the date of March 15. 



This new publication, which is supplementary to the well- 

 known "Fortschritte der Physik," now in its fifty-seventh vol- 

 ume, will be of great value to all active physicists and should be 

 well supported. 



