400 Scientific Intelligence. 



8. Electrical Vibrations in rarefied air without Electrodes. — 

 James Moser gives the following results of his experiments : — 

 A glass tube which contained a gas of constant rarefaction was 

 surrounded by a wider tube, and the rarefaction varied in this 

 by means of the air pump. The following results were obtained : — 



(a.) At the ordinary atmospheric pressure in the outer tube 

 the inner tube becomes luminous. 



(b.) With a sufficient rarefaction of the outer tube tbe phe- 

 nomenon is reversed: the inner tube becomes dark and the outer 

 one luminous. Here there is a screening action. 



(c.) The rarefaction was pushed further, the outer tube became 

 dark, the inner one luminous, so that to the eye the third stage 

 was like the first one. 



The more perfect vacuum gives, therefore, no screening action. 

 It has lost the power of conducting the electrical current. — Phil. 

 Mag., April, 1890, p. 375. j. t. 



9. Magnetization in strong fields at different temperatures. 

 — H. E. J. G. DuBois believes that his experiments show that 

 all doubts that have occasionally arisen in regard to the existence 

 of a limit of magnetization will be dissipated. He agrees with the 

 results of M. Goldhammer, that " magnetization affects all physical 

 properties of metals in a way generally depending on its direction. 

 Whenever the ensuing changes are odd functions of the magneti- 

 zation (both simultaneously reversing their sign), they are simply 

 proportional to it. In the case of even functions (always having 

 the same sign), they are simply proportional to its square. — Phil. 

 Mag., April, 1890, pp. 293-306. j. t. 



10. On the structure of the Line Spectra of the Chemical Ele- 

 ments. — J. R. Rydberg, of the University of Lund, gives the 

 following as the results of his study : 



(1.) The long lines of the spectra form doublets or triplets, in 

 which the difference {y) of wave numbers of their corresponding 

 components is a constant for each element. 



(2.) The corresponding components of the doublets form series 



of which the terms are functions of the consecutive integers. 



Each series is expressed approximately by an equation of the 



N" . 



form n=n n ; — t-=, where n is the wave number, m any posi- 



(m + yu) 2 ' J r 



tive integer (the number of the term), N , n and }x constants pecu- 

 liar to the series. 



The wave length (and the wave numbers) of corresponding 

 lines, as well as the values of the constants v, n , /j. of correspond- 

 ing series of different elements, are periodical functions of the 

 atomic weight. — Phil. Mag., April, 1890, pp. 331-337. J. T. 



11. Velocity of the Propagation of Gravitation. — M. J. Van 

 Hepperger, in a paper read before the Vienna Academy of 

 Sciences, has assigned an inferior limit to the velocity of propa- 

 gation of gravitation. It results from this limit that the time taken 

 by gravitation to travel the radius of the earth's orbit does not 

 exceed a second. — Nature, March 20, 1890, p. 472. j. t. 



