28o THE ORIGIN OF LIFE 



puseles are scattered freely within the substance 

 when the large aggregates are brought about. The 

 number of molecules is diminished and the free- 

 paths of the corpuscles correspondingly increased. 

 If the molecular concentrations be very great, 

 as also the charges on them, the effect on 

 the free-paths will be very considerable, and 

 then by some means, such as by the action of 

 violet or ultra-violet light, large molecular con- 

 densations are brought about and their charges 

 neutralised. Any free negative corpuscles that 

 remain will have a great opportunity of escaping 

 from the body. Their velocities will not merely 

 be increased by the more intense molecular attrac- 

 tion during the change in the molecular structure 

 of the body, but they will also have greater freedom 

 to diffuse out of the substance in virtue of the 

 increased length of the free-path. Consequently a 

 phosphorescent body, when exposed to the more 

 refrangible rays of the spectrum, will lose negative 

 electricity and emit a swarm of negative ions or 

 corpuscles. This phenomenon has been observed by 

 Lenard and Wolf (Wied. Ann., xxxvii. p. 443, 1889), 

 and is of the same nature as the well-known dis- 

 charge of negative electricity from a polished metal 

 surface. 



Whether the action of light is to produce similar 

 molecular agglomerations in metals so as to give 

 the corpuscles greater freedom, it is difl&cult to say ; 

 but the action of light on a metal, according to 

 this view, should be to diminish its resistance, and 



