( 570) 



It therefore seems probable to accept with Prof. Vok;t ^) that 

 the change of value of the assyniinetrj is due to differences in the 

 circumstances of the radiating vapour. 



5. The following table embodies the result of the calculations 

 according to (1) and (2) of my observations concerning line 5791. 



MERCURY LINE 5791. 



The last line in this table refers to the observations recorded in 

 § 1 of this paper. 



Dividing the numbers of the second column b}' those of the first 

 one we infer that the vibrating mass (probably wholly electromagnetic) 

 only amounts from 4-l()— i' to 2.10"^' gram per cm\ 



Accepting J. J. Thomson's value of e viz. 1,1. 10~-" electromagnetic 

 units, we may find the number N'. The number of electrons per 

 unit volume causing the radiation of the mercury line 5791 in a 

 vacuum tube, appears then in the circumstances of our experiments 

 and according to the magnetic force to lay between 8.10'^ and 4.10'*^ 

 per cm^ 



In these experiments the temperature of the vacuum tube may 

 be taken as somewhere bet w een 100^ and 120^. According to Hertz 

 the pressures of mercury vapour corresponding to these tempe- 

 ratures are 0.29 resp. 0.78 m.m. From these facts in connection with 

 other well know^n data we may conclude that the number of electrons 

 participating iji the emission of line 5791 is of the same order of 

 magnitude as the number of atoms present. 



There seems to be no obstacle in accepting this ]-esult and the 

 hypothesis that all atoms participate simultaneously in the emission 

 of light might even seem the most natural. It is however of some 



1) VoiGT. Physik. Zeilschr. 9. S. 1^20. 1908. 



