PHOSPHORESCENT MOLECULES 279 



from a slow process of combustion, as in the case 

 of phosphorus, and in that of the luminosity 

 of glow-worms and photogenic bacteria which are 

 catalytic in their nature. The process may 

 be compared to a form of catalysis, when 

 molecular and even chemical interactions take place 

 without any permanent chemical or physical 

 change in the constitution of the body : a catalyst 

 in this sense being a substance which, by its mere 

 presence, effects chemical reaction without entering 

 into the final product. First of all there is the for- 

 mation of an unstable compound, the action is set 

 going by the presence of a small quantity of the 

 impurity until stable equilibrium is reached, and a 

 series of chemical changes in which the final product 

 and the active impurity are the same as at the 

 beginning is the final result. 



An agglomeration of molecules takes place, and 

 by it an internal rearrangement of atoms in the 

 production of light, with the separation of atomic 

 groups of the same nature as those before the pro- 

 cess, whilst the fact that phosphorescence depends 

 so much upon the presence of impurities strongly 

 supports this view of the cause of luminosity. 



On the Effect of Molecular Concentrations on the 

 Freedom of Corpuscles 



Those large molecular agglomerations or centres 

 of force so formed appear to be positively charged 

 molecules, so that the corresponding negative cor- 



