p. C. WILHELMSEN, R. LUMRY AND H. EYRING 



89 



of absorption of oxygen was followed by the change in the pressure of 

 the oxygen. Because of the slowness of the reaction, the quantity of 

 oxygen absorbed can be taken as the concentration and can be pre- 

 sumed uniformly distributed throughout the solution. 



Various tests were performed to test the validity of the various 

 assumptions. As was stated earHer, the volume of the manometer and 

 reaction vessel was checked by comparison with the vessel used to 

 store oxygen. There was good agreement between the volume de- 

 termined this way and by actual measurement. Distilled water was 



30 



60 



Seconds 



Fig. 8. 



added to some of the solutions and the experiment was repeated to 

 check the assumption that the luminol concentration remained es- 

 sentially constant throughout the experiment. There was no difference 

 in repeated runs greater than the experimental error from other 

 sources. The rate of absorbing oxygen was changed by varying the 

 pressure of the oxygen, but no difference was noted when intensity 

 was related to the quantity of absorbed oxygen. 



Results 



Measurements were made relating the intensity and the change in 

 pressure of the oxygen above the reaction solution. The change in 



