﻿Thermions from the Salts of the Alkaline Earths. 137 



true emission of magnesium atoms carrying single charges 

 was obtained from both the chloride and the phosphate. 



Magnesium Chloride. 



The samples of this salt tested were from a supply of 



Kahlbaum's magnesium chloride " zur Analyse. " Measurable 



currents were obtained at comparatively low temperatures. 



The curves were erratic at these temperatures but improved 



at the higher ones. The data and results follow : — 

 in 



Magnesium Chloride. 



V- 



H. 



d. 



'2x. 



ejm. 





(e/m) K + 



408 



2915 



1-305 



•343 



218 



800 



249 



408 



2100 



1-305 



•302 



247 







407 



2400 



1-305 



•317 



320 







407 



2400 



T305 



•397 



428 







407 



2400 



1-305 



•397 



428 







The first values are probably due to potassium. The final 

 ones, which are for a temperature of about 1100° C, are 

 taken to indicate magnesium atoms carrying single charges. 



Magnesium Phosphate. 

 The curves for magnesium phosphate were belter, on the 

 whole, than for any of the phosphates already mentioned. 

 During twenty-four hours' heating the values of ejm fluctuated 

 between the value for potassium and that for magnesium. 

 The value obtained at the highest temperature corresponded 

 most nearly to the value for magnesium. In the following- 

 Table the data and results occur in order of increasing- 

 temperature. The final value is for a temperature of from 

 1100° C. to 1200° G. 



Magnesium Phosphate. 



V. 



H, 



d. 



2x. 



ejm. 



( e / w ) Mg+ + 



W*)k + 



400 



2400 



1-285 



•311 



279 



800 



249 



395 



2400 



1-285 



•321 



291 







395 



2400 



1-285 



•359 



365 







395 



2400 



1-285 



•343 



333 







395 



2400 



1-285 



•355 



358 







395 



2400 



1-285 



•355 



358 







395 



2400 



1-285 



•387 



423 





Magnesium Fluoride. 

 The curves for this salt were always irregular and variable, 

 but one pair of reliable curves was obtained, and that gave a 

 value of ejm corresponding to potassium. 



