Foundations of the Universe 257 



find out whether the emission came from the uranium itself or 

 from something associated wdth it, and for this purpose they made 

 a chemical analysis of great quantities of minerals. They found 

 a certain kind of pitchblende which was very active, and they 

 analysed tons of it, concentrating always on the radiant element 

 in it. After a time, as they successively worked out the non- 

 radiant matter, the stuff began to glow. In the end they ex- 

 tracted from eight tons of pitchblende about half a teaspoonful 

 of something that was a million times more radiant than uranium. 

 There was only one name for it Radium. 



That was the starting-point of the new development of 

 physics and chemistry. From every laboratory in the world came 

 a cry for radium salts (as pure radium was too precious), and 

 hundreds of brilliant workers fastened on the new element. The 

 inquiry was broadened, and, as year followed year, one substance 

 after another was found to possess the power of emitting raj r s. 

 that is, to be radio-active. We know to-day that nearly every form 

 of matter can be stimulated to radio-activity; which, as we shall 

 see, means that its atoms break up into smaller and wonderfully 

 energetic particles which we call "electrons" This discovery of 

 electrons has brought about a complete change in our ideas in 

 many directions. 



So, instead of atoms being indivisible, they are actually divid- 

 ing themselves, spontaneously, and giving off throughout the 

 universe tiny fragments of their substance. We shall explain 

 presently what was later discovered about the electron; mean- 

 while we can say that every glowing metal is pouring out a stream 

 of these electrons. Every arc-lamp is discharging them. Every 

 clap of thunder means a shower of them. Every star is flooding 

 space with them. We are witnessing the spontaneous breaking 

 up of atoms, atoms which had been thought to be indivisible. The 

 sun not only pours out streams of electrons from its own atoms, 

 but the ultra-violet light which it sends to the earth is one of the 

 most powerful agencies for releasing electrons from the surface- 



VOL. I 17 



