Chemistry and Physics. 465 



extremely low temperatures. Accordingly, for problems in sta- 

 tistical mechanics, it is not necessary to assume an absolute-zero 

 energy. 



Whereas pure diamagnetism can exist, such is not the case for 

 paramagnetism. The latter is always accompanied by the former, 

 since diamagnetism corresponds to thermal rotations about the 

 equatorial axes. With weak fields and low temperatures para- 

 magnetism may preponderate, but with stronger fields and higher 

 temperatures it passes over to diamagnetism. This accounts for 

 the phenomena of metamagnetism recently discovered by Weber 

 and Overbeck. — Ann. d. Physik, vol. xlix, p. 149, Feb., 1916. 



h. s. u. 



6. The Carriers of the Spectra of Hydrogen. — By carefully 

 weighing all of the experimental evidence associated with the 

 Doppler effect in the canal rays of hydrogen, J. Stakk has arrived 

 at the following important conclusions, (a) The series spectrum 

 and the band spectrum of hydrogen have different carriers. By 

 "band" spectrum Stark means the so-called " second spectrum " 

 or "many-line spectrum." (b) The carriers of the two spectra 

 of hydrogen have the same mass as that of the hydrogen atom 

 (m =1). (c) The carrier of the series spectrum of hydrogen is 

 the positive atomic ion. (d) The carrier of the band spectrum is 

 the neutral hydrogen atom, (e) The neutral hydrogen atoms, 

 while in a state of equilibrium and radiating sharp spectral lines, 

 do not occur in appreciable numbers as displaced or " moved " 

 particles in the canal ray stream, (f) The lines of the hydrogen 

 bands in the canal ray beam are not excited by the collision of 

 secondary canal rays but by the direct impact of the canal rays 

 themselves. 



Unfortunately the discussion is too long to be adequately repro- 

 duced in this place so that reference to the original paper must 

 be made for the details of the argument. — Ann. d. Physik, vol. 

 xlix, p. 179, Feb., 1916. h. s. u. 



7. The Primary X-Ray Spectra of Iodine and Tellurium. — 

 Since the investigations of the high frequency spectra of iodine and 

 tellurium, carried out independently by de Broglie and I. Maimer, 

 led to conflicting results with regard to the proper sequence of 

 these elements, the problem has been again attacked experimentally 

 by M anne Siegbahn. Moreover, since the earlier investigators 

 made use of secondary radiations, and since, in general, the results 

 obtained by this method are not as accurate as the ones obtained 

 by using primary radiations, Siegbahn employed primary X-rays. 

 The simple scheme of using a cooled silver anticathode on the 

 surface of which a compound of iodine or of tellurium was pro- 

 duced (by placing the pure element in question on the silver disc 

 and then warming) was found to work very satisfactorily. The 

 spectrograms obtained by rotating a rock salt crystal showed two 

 sharp lines for each of the elements, iodine, silver, and tellurium. 

 The wave-lengths were based on that of the line ^ x of silver since 

 this has been accurately determined as - 5011 X 10 _8 cm. corre- 



