﻿in the Emission of .Positive Thermions from Salts. 143 

 Table II. 





Thermionic 



Equilibrium 



Time. 



Current in 



Pressure in 





Amperes. 



in in. of Hg. 



8 33 p.m. 







5xlQ -5 



8 34 







38xl0 -5 



8 37 







68xl0~ 3 



8 42 







91X10 -5 



8 46 



<5xl0~ 12 



99x10"'' 



8 54 



<5xl0 _12 



99xl0" r> 



9 11 



<5xl0- 12 



114X10-" 5 



9 '23 



<5xl0~ 12 



129xl0~ 5 



10 10 



-c5xl0~ 12 



121X10 -5 



Heating an 



'I pumping coat 



inued overnight. 



1 9 00 A.M. 



48XKT 12 



91xl0~ 5 



10 00 



48X10" 12 



99X10 -5 



2 30 r.M. 



38xl0- 12 



76X10- 5 



8 00 



<5xl0" 12 







84X10" 5 



being 230. At something over 1000° C. the equilibrium 

 pressure was a little higher than any noted in the experiment 

 on strontium chloride. A spectroscopic examination of the 

 gas indicated mercury vapour and carbon monoxide as in the 

 former case. Determination of e/m at this temperature gave 

 104 and 105 which are in agreement with HI, one-half the 

 electrolytic value for strontium. 



Taken together these results constitute a strono; argu- 

 ment against the hypothesis that any part of the positive 

 thermionic current from a heated salt is carried by carbon 

 monoxide. 



Another series of experiments has been made to determine 

 the role played by the gas in contact with a surface of heated 

 salt. In particular to determine if the increase in thermionic 

 current at constant temperature which Garrett (L c.) and 

 Horton (7. r.) have shown to be brought about by an increase 

 of gas pressure up to one or two millimetres is, in fact, duo 

 to an absorption of atoms or molecules of the gas and their 

 re-emission in a charged condition. 



For this purpose it was proposed to study the behaviour 

 of the curves for some salt as the gas pressure in the 

 apparatus was gradually increased. It was desirable, el' 

 course, to choose a salt which should give a large stead}" 



