of Hydrogen and some other Gases. 333 



It becomes now clear that the volume susceptibilities of 

 the nitrogen and argon present in the atmosphere are not 

 negligibly small, as was believed to be the case ; and that 

 the sum of their values amounts to a little above one per 

 cent. of the susceptibility of air. 



§ 9. Hydrogen. 



Hydrogen is one of the gases the magnetic susceptibility 

 of which has been comparatively well studied. Nevertheless, 

 owing to the difficulties which accompany the experiments, 

 we have as yet no reliable experimental value of its magnetic 

 susceptibility; even its sign was not decided till quite 

 recently. But recent investigators seem to agree in the 

 view that hydrogen has a diamagnetic susceptibility, and 

 now the determination of an exact value of its susceptibilitv 

 becomes an outstanding problem. 



Quincke * first determined the magnetic susceptibility of 

 hj'drogen, and found as its susceptibility a value 



K = +0-0003 xlO" 6 . 



Bernstein f published the results of his experiments on the 

 magnetism of some gases in his dissertation at Halle, and 

 gave as the susceptibility of gaseous hydrogen, 



k= -0-005 xlO" 6 . 



Assuming the additive law, Pascal % calculated the atomic 

 susceptibility of hydrogen from the study of some organic 

 compounds ; the result of his calculation being 



x = -3-05x10-°. 



Kammerlingh Onnes and Perrier§ measured the magnetic 

 susceptibility of liquid hydrogen and found as its volume 

 susceptibilitv, 



k= -0-186 xlO" 6 . 



Taking for the density of liquid hydrogen a value 

 obtained by Dewar 0'07, he deduced as the specific 

 susceptibility of liquid hydrogen, 



x = -2-7 xlO" 6 . 



No account of the experimental details was given in their 



* G. Quincke, loc. cit. f Bernstein, loc. cit. 



X P. Pascal, loc. cit. 



$ H. KammerliDgli Onnes and A. Perrier, Amsterdam Pruc. xiv. 

 p. 121 (1911). 



