48 ORIGIN AND NATURE OF LIFE 



metre (or about 1 -500th of an inch) in thick- 

 ness, it requires 5 millimetres of aluminium 

 to get rid of the beta rays nearly completely, 

 and a column of about 50 centimetres, or 

 twenty inches, in English measure, is calcu- 

 lated to be necessary for the absorption of 

 gamma rays. The relative penetrating powers 

 are thus approximately as 1 : 100 : 10,000. 



While the alpha and beta rays consist of 

 minute particles, the size and energy content 

 of which can be accurately measured and 

 their actual mass determined, the gamma 

 rays are waves or disturbances in the ether 

 propagated in irregular pulses or surges with 

 the velocity of light. 



It is the alpha and beta particles which 

 interest us chiefly here as being the initial 

 stage in the synthesis of matter, and the 

 commencement of that long train of interplay 

 between matter and energy which leads up 

 in increasing complexity of molecular structure 

 and attendant change in the inhabiting 

 energy till man is reached. 



The beta particle is by far the smaller 

 of the two, and is identical with the electron, 

 or electricity bearer. The form of energy 

 which it carries is electricity, and it is the 

 movement of a constant stream of millions 

 of millions of such beta-particles or electrons 



