Chemistry and Physics. 187 



calculated by F. W. Clarke, and by using these percentages 

 as ordinates and the corresponding atomic weights as abscissas, 

 shows that there is evidence of periodicity in the abundance of 

 the elements. The curve which is carried only as far as nickel 

 shows four maxima at oxygen, silicon, calcium and iron, and is 

 regular enough to be very suggestive and interesting. — Zeitschr. 

 physikal. Chem., lxiv, 707. h. l. w. 



6. Velocity of Rontgen Ray* ; also their Influence on the 

 Brush Discharge. — Erich Marx has previously measured the 

 velocity of these rays (Ann. der Phys., xx, p. 677, 1906) by a 

 null method, and in order to justify his use of the method he 

 employed follows with another paper which is devoted to the 

 theory of the method. He discusses various phenomena of the 

 rays which come into prominence in his method, and naturally 

 treats also of ionization. — Ann. der JPhysik, No. 1, 1909, pp. 37- 

 56, 153-174. j. t. 



7. Radiation of Uranium JC. — Uranium X was obtained by 

 the Moore-Schlundt and Becquerel method. Heinrich Willy 

 Schmidt gives with many details the results of his investigation 

 of the radiation of this substance. 



( 1 ) The hard /3-rays gave 



^ = 2-76'10 10 cm. sec -1 

 € /m=0-67'10 7 E.M.E. 



(2) The soft rays are absorbed by aluminium according to an 

 exponential law, and are deviated in a magnetic field in the 

 manner of negative particles. 



(3) The curves of absorption, in different substances, varies 

 much with the distribution of the radiation. 



(4) An under limit is given for the absolute value of the 

 reflection of the /3-rays for very thick plates. The absolute 

 value of the reflected radiation is greater for the hard /3-rays 

 than for the soft rays. — Physikal. Zeitschrift, Jan. 1, 1909, pp. 

 6-16. j. t. 



8. Influence of Self Induction on Spark Spectra. — G. Berndt 

 contends that the criticisms of Neculcea and Hemsalech on 

 his investigation of the influence of self induction on spark 

 spectra (Diss. Halle, 1901) do not consider the factor of time 

 of exposure of the photographic plate, for the introduction 

 of self induction greatly weakens the intensity of the spark. — 

 Physikal. Zeitschrift, Jan. 1, 1909, pp. 28-29. j. t. 



9. Ionization of Gases, by Spark and Arc. — It is known that 

 gases subjected to high temperatures in the neighborhood of 

 electric sparks or the electric arc preserve their increased con- 

 ductibility much longer than gases subjected to ultra-violet light, 

 X-rays, or a- and /8-rays. Heinrich Rausch, in a preliminary 

 paper, investigates this property with a number of gases, among 

 which were ordinary lighting gas, acetylene, hydrogen, carbu- 

 retted hydrogen. He found a very long persistence of conducti- 

 bility in lighting gas and acetylene. — Physikal. Zeitschrift, Oct. 

 25, 1908. j. t. 



