Thermions emitted by the Alkali Sulphates. 997 



General Considerations. 



The values of e/m and m which, according to the view of 

 these phenomena developed in the present paper, are cha- 

 racteristic of the positive ions emitted by the pure sulphate of 

 the alkali metals, are collected together in the folio wi no- 

 table. The values which are believed to be due to the 

 presence of imparities in the material are omitted from the 

 table. 



Substance. 



Li 2 S0 4 

 LLSO. 



Time 

 heated 

 (hours). 



e/m 

 (EM. 



units). 



m 



(H = l). 



Average 

 value of 



Na 2 S0 4 



Na 2 S0 4 



Na 2 S0 4 



Na 2 S0 4 



K 2 S0 4 



K 2 S0 4 



K 2 S0 4 



K 2 S0 4 



K 2 S0 4 



K 2 S0 4 



Eb 2 S0 4 



Cs 2 S0 4 



Cs 2 S0 4 



12 



44 



52 



8 



21 

 13 

 15 

 

 6 

 24 

 36 

 42 

 60 





 18 

 23 



1760 

 1735 

 1300 



413 



430 



439 



439 



261 



261 



261 



272 



266 



266 



101 



101-8 

 59-1 

 591 



557 

 743 

 23-4 

 22 5 

 220 

 220 

 37-0 

 370 

 370 

 355 

 36 3 

 36-3 

 96 

 95 



163 



163 



22-5 



36-5 

 96 



140 



Atomic 



weight of 



metal. 



7 05 

 7 05 

 7 05 

 23-05 

 2305 

 2305 

 2305 

 39T5 

 39-15 

 39-15 

 39-15 

 39-15 

 3915 

 85-5 

 132-9 

 132-9 

 132-9 



The numbers in the last three columns of the table show 

 conclusively that the positive ions emitted by the sulphates of 

 the alkali metals are atoms of the constituent metal. The 

 range of e/m, m, and of the atomic weight for the different 

 metals is so great that, although the accuracy of the measure- 

 ments is not, perhaps, all that might be desired, particularly 

 in the case of the elements of higher atomic weight, never- 

 theless the general agreement of m over so wide a range 

 is such as to leave no room for escape from the above 

 conclusion. 



It also follows that the positive ions emitted by the sulphates 



