Foundations of the Universe 



temperature. It is such instruments, multiplied by the score, 

 which enable us to do the fine work recorded in these pages. 



3 

 THE DISCOVERY OF X-RAYS AND RADIUM 



The Discovery of Sir Wm. Crookes 



But these wonders of the atom are only a prelude to the more 



romantic and far-reaching discoveries of the new physics the 



wonders of the electron. Another and the most important phase 

 of our exploration of the material universe opened with the dis- 

 covery of radium in 1898. 



In the discovery of radio-active elements, a new property 

 of matter was discovered. What followed on the discovery of 

 radium and of the X-rays we shall see. 



As Sir Ernest Rutherford, one of our greatest authorities, 

 recently said, the new physics has dissipated the last doubt about 

 the reality of atoms and molecules. The closer examination of 

 matter which we have been able to make shows positively that it 

 is composed of atoms. But we must not take the word now in its 

 original Greek meaning (an "indivisible" thing) . The atoms are 

 not indivisible. They can be broken up. They are composed of 

 still smaller particles. 



The discovery that the atom was composed of smaller par- 

 ticles was the welcome realisation of a dream that had haunted the 

 imagination of the nineteenth century. Chemists said that there 

 were about eighty different kinds of atoms different kinds of 

 matter but no one was satisfied with the multiplicity. Science 

 is always aiming at simplicity and unity. It may be that science 

 has now taken a long step in the direction of explaining the 

 fundamental unity of all the matter. The chemist was unable 

 to break up these "elements" into something simpler, so he called 

 their atoms "indivisible" in that sense. But one man of science 

 after another expressed the hope that we would yet discover 



