Disappearance of Gas in the Electric Discharge. 705 



On the other hand, it has been noted that the amount of 

 hydrogen that can be absorbed when the glow-discharge 

 passes is definitely less than that absorbed without the 

 discharge. This difference is due to evolution by bombard- 

 ment. The difference is certainly decreased by the addition 

 of phosphorus vapour, even when there is not enough to form 

 a yellow bulb ; but there is no evidence that, while the bulb 

 does not turn yellow, the sign of the difference can be 

 reversed by phosphorus and more absorbed with than with- 

 out it, The marked increase in the absorption of hydrogen 

 which is obtained with an unlimited supply of phosphorus 

 vapour is invariably associated with the formation of a 

 " yellow" bulb, the depth of the coloration of which increases 

 with the amount of hydrogen absorbed. 



Summary. 



The paper is a continuation of that in Phil. Mag. xh 

 p. 585, Nov. 1920. It discusses the disappearance under the 

 electric discharge of hydrogen, carbon monoxide, nitrogen, 

 argon, both in the absence and the presence of phosphorus 

 vapour. 



§ 12. In the presence of incandescent tungsten, hydrogen 

 disappears without the passage of the discharge, as discovered 

 by Langmuir. The gas disappearing adheres without change 

 to the surface of the glass, especially to the cooler parts 

 of it, 



§ 13. .When the discharge passes, the rate of disappearance 

 of hydrogen is not greatly altered ; but the phenomenon is 

 complicated by the simultaneous liberation of absorbed gas 

 by bombardment and by the appearance of water vapour. 

 The gas that has disappeared is again adhering to the glass 

 walls either as hydrogen or as water. 



§ 14. In the discharge, carbon monoxide is converted into 

 dioxide (see § 10) ; the dioxide, as well as the original 

 monoxide, adheres to the glass walls and can be liberated 

 thence by heating. The quantity of C0 2 which will adhere 

 to the glass is very much greater than that of hydrogen 

 which will so adhere. 



§ 15. Nitrogen disappears under the discharge, but cannot 

 be liberated again by baking the evacuated vessel. At the 

 same time the filament wastes and the walls are blackened. 

 It is probable that Langmuir's nitride WN 2 is formed, but it 



