3i6 THE ORIGIN OF LIFE 



indicate the problem proposed in the case of 

 luminosity in terms such as these. When billiard 

 balls knock about, their translational energy is 

 quickly turned into more and more rapid internal 

 motions until it all gradually gets degraded into 

 heat. The question is why the same does not go 

 on in molecules. 



It is generally assumed that there exists some 

 mechanism, in all bodies, by which rapid vibra- 

 tions, when absorbed, become gradually changed 

 into the slow kind of vibrations that correspond 

 to the average temperature of the body. In most 

 bodies this action is supposed to take place pretty 

 rapidly and continuously. In all probability, in 

 solids and in liquids vibrations of intermediate 

 rates are about equally excited, and are similarly 

 affected; while in fluorescent and phosphorescent 

 bodies these vibrations, on their way down from 

 the rapid to the slow periods, corresponding to the 

 temperature of the body, excite the fluorescent and 

 phosphorescent rates of vibration intensely ; and 

 these vibrations, being only very slowly turned 

 into the slower rates, as well as pretty intensely 

 radiated, we see them as fluorescent and phos- 

 phorescent light. 



The question is why all the vibrations do not 

 get converted into more and more rapid ones 

 instead of vice versd. The answer is that they do 

 get so converted into shriller and shriller vibra- 

 tions, but that the energy of these vibrations, 

 when their frequency exceeds a certain limit, is 



