288 THE ORIGIN OF LIFE 



servations on the change of absorption during 

 fluorescence (Burke, Philosophical Transactions, 

 1898), it has appeared to the author that the 

 phenomenon of fluorescence necessarily involves the 

 temporary formation of new molecular aggregations 

 to which the new emission and absorption spectra 

 of fluorescent substances are due. 



Thomson {Phil. Mag., December, 1895) has 

 indicated the importance, from a physical point, of 

 molecular aggregates in chemical theory, and his idea 

 of chains of molecules in carrying the discharge in 

 his " Eecent Researches " is, we venture to think, 

 one of the most useful conceptions in the theory 

 of luminosity. The view put forward here that 

 luminosity is a visible manifestation of a kind 

 of catalytic action would be greatly strengthened 

 if chains of molecules could be formed. The one 

 strong objection, that such chains of molecules if 

 they existed would very quickly be broken up 

 by the bombardment of other molecules, does not 

 appear to be sound, since the linkage between 

 the molecules may be sufiiciently great to enable 

 them to hold together for some time, and this 

 would be much longer in phosphorescent substances 

 than in non-phosphorescent ones. Furthermore, 

 Poynting has shown (loc. cit.) that spheres the size 

 of molecules, if they radiate intensely, would exert 

 considerable repulsive force on each other. 



The small fall of potential in the positive 

 column is a matter to which much attention has 

 been given recently. There can be no doubt that 



