474 



to our knowledge. We see In this a contiimalion of the view that 

 the atoms both absorb and emit energy in quanta, at the same time 

 an interaction between the two regions, which latter finds expression 

 in a related region of investigation, among others in Klkin and 

 Rosseland's theory M- 



The well-known theoretical parallelism between these two regions 

 and the simnltaneons parallelism between the observations on the 

 pressure effects and the light emission which have now been expe- 

 rimentally shown objectively, corroborate anew the close relation, 

 the unity between these tioo classes of phenomena. 



§ 7. Summary. 



1. Our priority witii regard to the "positive" pi-essuie effect is 

 established. 



It is shown that A. RfJTTENAUER's experimental investigations quan- 

 titatively confirm the theoretical view and formulae about the pressure 

 effect found hy us, which we gave befoie. This eslablisiies confirms 

 for an extensive region of validity defined in ^ 5 that the pressure 

 dijferences chiefly occur in consequence of mass-ti-ansportation by the 

 electric current. 



2. It is desirable to replace the emperical formula given by 

 A. RüTTENAüER for the pressure effect bj two formulae derivable 

 from the theory, dependent on the ratio between the free path of 

 the corpuscles and the (round) diameter of the tube, viz.: 



A i^Ml A \/Ml 



^p—f — 77,— • 'f' (9) resp. /\ p = f -— . <r (g) 



JJ p Ir 



in which (p {g) represents a function of the potential gradient, which 

 can assume approximately the form bg in definite regions ; in which 

 b represents a constant the value of which is different for different 

 gases. 



3. It is shown that the opinion advanced by F. Skaupy that the 

 pressure effect would be determined by the elastic electi-on impact, 

 is untenable. 



4. The significance of the simultaneous parallelism of the quan- 

 titatively and objectively measured light and pressure effects with 

 regard to the theory of the quanta is pointed out. It confirms that 

 tlie atoms both emit and absorb energy in quanta. 



5.' Attention is drawn to the desirability of extending the investi- 

 gations, in particular also to argon. 

 Dordrecht, October 11, 1922. 



1) Klein en Rosseland. Zeitschr. f. Physik. 4, 46 ('21). 



