﻿130 



Mr. Clinton J. Davisson on the Positii 



Barium Chloride. 

 In experiments upon this salt small crystals of Kahlbaum's 

 barium chloride " zur Analyse " were fused on the upper 

 surface of the strip in air ; otherwise the observations were 

 carried out as already described. All but one of the experi- 

 ments on this salt were made with the apparatus used by 

 Richardson. The results from four different samples of the 

 salt may be summarized as follows : — 



Barium Chloride. 



V. 



H. 



d. 



2x. 



e/m. 



"~55 





143 



4600 



•532 



•076 



142 



137 



4600 



•532 



•07(> 



60 



1 



129 



4600 



•492 



•082 



80 





123 



4600 



•502 



•092 



88 





123 



4600 



•502 



•089 



81 





123 



4600 



•502 



•087 



77 





208 



2915 



1*28 



•247 



63 





Mean = 72 



Here again the observed values of e/m, though varying 

 through a great range, are distributed about the value 

 corresponding to barium atoms carrying single charges. 



The temperature required to produce a measurable current 

 was 1000° C. or more, as in the case of the sulphate. A 

 larger and more persistent current was, however, obtainable. 



Barium Fluoride. 



The samples of this salt were prepared from the barium 

 chloride used in the experiments on that salt and Baker's 

 analysed hydrofluoric acid. 



A very high temperature, considerably over 1000° C, was 

 required to produce a measurable current. From three 

 different samples it was only once possible to obtain more 

 than one pair of curves before the current, even at the 

 highest temperature, had diminished below the limit of 

 observation. The following results obtained from this salt 

 are similar to those obtained from the sulphate and chloride. 



Barium Fluoride. 



V. 



H. 



d. 



2.i- . 



c m. 



142 













400 



2915 



1-28 



•173 



58 



399 



2915 



1-29 



•173 



56 





401 



2915 



1-285 



•191 



70 



| 



401 



2915 



1285 



•191 



70 



j 



Mean =64 



