Cathode Fall in Helium and Argon 



15 



do not agree. All, except one, are higher than the mobihty of 

 helium, 3.9 X 10^, computed from measurements of Franck and 

 Polil made at atmospheric pressure,^^ the highest value obtained 

 being approximately five times as high as their value. 



Argon. — The argon used was from a bulb obtained from the 

 Linde Gas Products Company and contained a trace of nitrogen 

 as an impurity. The argon was introduced into the discharge tube 

 without any further purification except drying — the tube being 

 " washed out " by repeated fillings and evacuation. The results 

 are incorporated in Tables III, IV, and V, and are shown graphi- 

 cally in Figs. 6, 7, 8, 



sJPiT 



-iSO 



3^S 



Soo 



V 



Ji2.S 



^00 



/PS 



/so 



Volts 



/zs 



.A 



J L 



.ZO 



J I L 



o -O o/bs e.ti^(Z d 



>f ^ Com/Si/ ted 



I ■ I I I I I I i 



.30 



Fig. 7 



.V^ c/^. 



^" Franck & Pohl, V crh. d. D. Phys. Ges., 9, p. 104, 1907. 



