produced by the Splashing of Mercury. 



Positive saturation current on the first electrode . . P 



Negative saturation current on the first electrode . N 

 Positive current obtained with a voltage of 600 on 

 the first electrode, the current being taken on the 



second electrode p 



Negative current similarly obtained n 



473 



p. 



v. 



N. 



n. 



170 



13, 14, 15 



200 



15, 15 



79 



13,14 



164 



12, 16 



175 



19, 20, 20 



224 



19. 15, 16 



114 



9,8,8 



145 



9,6,7 



The values for the positive and negative currents on the 

 second electrode, with a large voltage on the first ; show a 

 remarkable equality despite the fact that the total positive 

 and negative currents differ, although not to the same extent 

 as the positive and negative currents produced by the 

 splashing of mercury. lithe mercury were allowed to splash 

 and the air drawn through a tight cotton-wool plug 2 inches 

 long before reaching the testing vessel, it was found that 

 ions were still present. These, again, are exceedingly slow 

 ions that have passed the plug, or else they have been pro- 

 duced from doublets after they have passed the plug. Similar 

 results were obtained by Garret and Willows for the ions 

 produced by the halogen compounds of zinc (Phil. Mag. 

 1904, vol. viii. p. 437). 



Summary. 



(1) Splashing mercury on an iron plate produces a large 

 •excess of positive ions over negative ions. 



(2) A considerable proportion of these ions have a very 

 small velocity. 



(3) The amount of ionization depends on the nature of the 

 surface on which the splashing is produced. 



(4) The current- voltage curves for the positive ions show 

 peculiarities which may be most readily explained by 

 snpposing the presence of neutral doublets, which are broken 

 up by the field or other means. Below certain heights these 

 doublets are not produced. 



