FRANK H. JOHNSON 



289 



TIME (MIN) 



Fig. 14. Rate of change in intensity of luminescence in the saturated system 

 following application (on) and release (off) of pressure at different tem- 

 peratures. The half time (f^^) for the change between steady states is indi- 

 cated below the respective lines. The lines, plotted relative to an arbitrary 

 value of 100 at t = 0, represent the progressive difference in intensity, with 

 time, between the peak of the spike and steady-state level under pressure, 

 and the progressive difference, with time, between the lowest point of the 

 dip and the steady-state level after pressure, respectively. 



although the rates increase with rise in temperature, they do not vary 

 significantly with the amount of pressure at a single temperature. The 

 diflFerences in rates under increased as compared to normal pressure 

 are small but perhaps significant. 



- The following simplified diagram is helpful in picturing the rela- 

 tionship of some of the reactions involved in luminescence of the 

 saturated system at low temperatures: 



A 



ki 



B — 



-> C + light 



C 



In this diagram, A stands for DPNHo + FMN, B stands for DPN + 

 FMNHo, and C and C stand for the products of the luminescent and 



