272 THE ORIGIN OF LIFE 



If the surface-tension is diminished by not more 

 than one per cent., enough energy is liberated 

 to raise the temperature of the film of oxygen 

 10"^ cms. in thickness, through several degrees 

 centigrade. 



The luminosity produced by the motion of 

 mercury on glass appears to be produced in a similar 

 manner by this breakdown of surface tension on the 

 film of oxide, whilst the extraordinary brightness and 

 efficiency of the discharge through mercury vapour 

 presents a problem of intense interest, and in fact 

 of great practical importance with which we hope 

 to deal presently. 



The author has found that the negative ions 

 tend to extinguish the glow, whereas, on the other 

 hand, the positive discharge can be sent through 

 the gas with facility, without affecting its duration, 

 as the cathode rays spoil the phosphorescence in a 

 very short time, by producing further condensation. 



Chemical Reaction in High Vacua. 



The chemical changes which go on at the 

 surface layers, of molecules as well as of larger 

 bodies, which we have been considering, may be 

 such as we have no experience of at ordinary 

 temperatures, from experiments with large masses 

 of the substances. 



Thus the combinations which go on more freely 

 between gases condensed on the surfaces than 



