﻿13-4 Mr. Clinton J. Davisson on the Positive 



Strontium Phospliate. 



The emissioD from strontium phosphate was found to be 

 similar to that from the corresponding salt of barium. The 

 specimen examined was prepared from strontium nitrate 

 of ; ' tested purity "' supplied by Eimer and Amend, and 

 Kahlbaum's ammonium phosphate. The ammonium phos- 

 phate was the same as that used in the preparation of barium 

 phosphate : it seems probable that this was the source of the 

 impurity. The following data were obtained : — 



Strontium Phosphate. 



A". 



H. 



d. 



±V. 



c m. 



- ? m) K+ 



207 



2915 



1-32 



'ooo 



287 



222 249 



207 



2915 



1-32 



•540 



284 







401 



291.3 



1-32 



•381 



281 







400 



2960 



1-32 



■381 



276 







400 



2915 



1 32 



■381 



281 







After making these determinations, what remained of the 

 phosphate was removed from the strip with nitric acid and 

 distilled water. Before using the strip for any other salt 

 the apparatus was reassembled and the cleaned strip sub- 

 jected to a preliminary heating to reduce its own emission 

 again to zero. As was usually found in such cases, a 

 measurable though short-lived current was easily obtained. 

 A determination of e/m at the lowest temperature giving a 

 measurable emission yielded 2lj±. which was taken to indicate 

 potassium. After this initial emission had disappeared the 

 temperature of the strip was increased and additional deter- 

 mination- made with the following results : — 



V. H. 



d. 

 1-32 



2a\ 



e m. 



" Brf4 



394 2915 



•244 



108 



222 



418 2915 



1-32 



•260 



131 





418 2915 



132 



•267 



138 





Though great reliance may not be put upon these results, 

 their agreement with half the electrolytic value for strontium 

 suggests that the emission may have been due to strontium 

 phosphate or to strontium nitrate which remained on the 

 strip after the cleaning. 



