1)24 Prof. J. de Kowalski : Applications of the Theory 



According to this hypothesis the phenomena of phosphor- 

 escence and fluorescence are explained as follows : — In 

 strongly electronogenous systems light produces the expulsion 

 of electrons in considerable quantities. Now, as these electrono- 

 genous systems are intimately bound up with the luminophorous 

 systems, the secondary rays are able to penetrate into these 

 latter provided their velocity be in proper accord. The critical 

 value of the internal energy of the luminophorous systems will 

 soon be surpassed and light will result*. 



In the case of fluorescent bodies these electrons are only 

 temporarily absorbed. The luminophorous s3 T stem becomes 

 luminous whilst it is being traversed by the electrons. In 

 the case of phosphorescent bodies the electrons are absorbed 

 by the luminophorous system and this latter remains luminous 

 until it has shot out a quantity of electrons and radiated 

 energy, to the extent of causing its internal energy to fall 

 beneath the critical value. 



The fundamental principle of my theory, namely, the 

 coexistence of two kinds of systems of corpuscules in phos- 

 phorescent and fluorescent bodies, is amply confirmed by 

 experimental facts. 



II. — In the matter of phosphorescence we have the works 

 of Lenard, Klatt, Urbain, de Visser, and Waentig, which 

 prove that in order to produce phosphorescence, two different 

 bodies, which they call the solvent and the active metal, must 

 be brought into contact. The active metal plays the role of 

 the luminophorous system. Now as the sulphides employed 

 possess, to a high degree, the power of producing secondary 

 rays under the influence of light, it is very probable that 

 they contain the electronogenous systems. 



As regards fluorescent bodies, the interesting work of 

 Kauffmann on the constitution of organic fluorescent bodies, 

 likewise confirm my manner of viewing the matter. The 

 molecular groupings which this scientist calls fluorogenous 

 and luminophorous, correspond to my electronogenous and 

 luminophorous systems. 



III. — My theory permits me to establish a relation, amply 

 confirmed by experiment, between the intensity of phos- 

 phorescence and the time. 



Let E be the initial energy of a luminophorous system, 

 before it is acted upon by secondary rays. Under the 

 influence of light the electronogenous system which surrounds 

 the luminophorous will cause these latter to receive and absorb 



* Quite recently Prof. Lenard called attention to the importance of 

 secondary rays for phosphorescence, but in a quite different manner from 

 that in which I am doing it here. 



