﻿Thermions from the Salts of the Alkaline Earths. 129 



These values of ejm do not agree with the value of ejm 

 for barium in electrolysis as the experiments of Richardson 

 might lead one to expect. It will be seen, however, that 

 the mean of the experimental values approximates to one-half 

 the value computed from chemical data. That this approxi- 

 mation is not accidental, and that the large discrepancy is 

 due to errors inherent in the experimental method, are 

 rendered more certain by the results of experiments upon 

 the other salts of barium,' as well as those upon the salts of 





—-— 



™™_ 



Fig. 



3. 



! 



1 



i 



/^ 



\ 







-1-: 













3 





• mm. 







. 



i 1 



the other alkaline earths. Such a relation, though unex- 

 pected, receives a ready interpretation upon the supposition 

 that the ions are single atoms of barium minus single 

 electronic charges, instead of such atoms minus double 

 electronic charges as in chemical reactions. 



Other curves from this supply of salt could not be obtained 

 on account of the gradual diminution of the thermionic 

 current. 



The curves, fig. 3, exemplify an annoying type of 

 irregularity not infrequently met with in these observations. 

 It is evident that a decided change occurred in the distri- 

 bution of emission while curves (1) and (2) were being 

 taken, owing perhaps to a slight contortion of the strip, or to 

 a change in the surface of the salt. In such cases curves were 

 always taken with the magnetic field alternately in one sense 

 and in the other until a pair of similarly shaped peaks was 

 obtained. It is probable, however, that these time variations 

 were always operative to some extent, and that to them are 

 due, in part, the irregularities to be found throughout the 

 results. 



Phil. Mag. S. 6." Vol. 23. No. 133. Jim. 1912. K 



