CHAPTER VI. 

 THE ALPHA-, BETA- AND GAMMA-RAYS. 



THE ALPHA-RAYS. 



The secret of the alpha-rays drops into our hands as soon 

 as we compare them in their properties with the positive 

 ions of Part III. The positive ions, as we learned, were 

 tiny bodies laden with positive electrification flying off, 

 under certain conditions, from gas flames, red-hot metals 

 and other bodies. We learned that their velocities were 

 anywhere from ten to twenty thousand miles a second, that 

 their mass was about twice that of a hydrogen atom and 

 that on the application of intense magnetic force they could 

 be slightly bent or deviated. Now the alpha-rays from 

 radium have properties identical with those stated above. 

 They are the positive ions, but instead of requiring high 

 temperatures or other exceptional conditions for their exist- 

 ence they fly off from the substance radium in its natural 

 normal state. On the basis of all the evidence necessary 

 to convince a reasonable man, the alpha-rays from radium 

 are streams of little bodies with a mass about twice the mass 

 of the hydrogen atom flying off from radium and laden with 

 positive electricity. Their velocity is about 20,000 miles a 

 second! Compare this velocity with that of the swiftest 

 projectile that man can fire from a gun. A rifle bullet 

 travels with a velocity of about half a mile a second, and 

 we consider this speed of transit extreme, but these pro- 

 jected atoms have a velocity 40,000 times greater. Now 

 the energy of any moving body increases as the square of 



(105) 



