286 THE ORIGIN OF LIFE 



When a discharge is sent through a vacuum 

 tube without electrodes, by the discharge of a 

 Ley den jar through a few turns of wire wound 

 round the tube, the effect produced inside the tube 

 is due to the induced alternating current in the 

 gas, and consists of a luminous ring discharge 

 which gives rise to ionisation of the gas and to 

 molecules, or groups of ions such that, if they 

 carry a free charge of electricity, their size must 

 be, for molecules, very large. They have a certain 

 amount of energy stored up in them which is 

 radiated away in the form of light. The duration 

 of these more or less unstable molecules is greatly 

 increased by removing them from the presence of 

 the gas in which the discharge is produced 

 (Burke, Philosophical Magazine, March, 1901). 

 Thus if the phosphorescent gas is made to diffuse 

 through narrow metal tubing from the bulb in 

 which it is produced into another exhausted to 

 the same degree, the metal tubing being at zero 

 potential with the earth so that ordinary ions in 

 the first bulb cannot diffuse into those in the 

 second, the phosphorescence in the second bulb is 

 greatly increased in brightness as well as in 

 duration, from which we may gather that the 

 presence of ions diminishes the duration of the 

 glow and also that separate phosphorescent mole- 

 cules exist and that if they carry a charge, they 

 must be very large. ^ 



^ See J. S. Townsend on " Diffusion of Ions," Philosophical 

 Magazine, 1898. 



