Sir Ernest Rutherford 231 



head-on with a nitrogen atom, and that the result of such 

 a collision was to break up the structure of the atom 

 to some extent and to bring about what the alchemists 

 of old were always striving for — a transmutation. In 

 simpler words, part of the nitrogen was actually turned 

 into hydrogen. 



Sir Ernest continued his experiments, working upon 

 fluorine, sodium, aluminium, and phosphorus, and in 

 every case the result was the same. In all, twelve of the 

 lighter elements were tested, and in every case a hydrogen 

 nucleus or proton was driven out at great speed. 



Having read so far, you will doubtless wish to know 

 how Sir Ernest and his assistants could possibly satisfy 

 themselves about the results stated. The answer can be 

 given in one word — rather long, yet very familiar — 

 spinthariscope. The spinthariscope, originally invented 

 purely as a scientific instrument, has become a scientific 

 toy, and very many people have seen the brilliant little 

 flashes which occur when a morsel of radium is allowed 

 to bombard the screen of zinc sulphide. In Sir Ernest's 

 experiments each proton liberated could be detected by 

 its flash when it struck the screen. 



Since these first experiments, which were made at 

 Manchester University, other methods of detecting these 

 minute particles have been perfected. Each as it enters 

 a chamber can be made to record itself. It can be made 

 to ring a bell, to click on a telephone receiver, or to deflect 

 an instrument. 



It may be mentioned here that by the use of a vacuum 

 tube radio amplifier, which magnifies the sound a hundred 

 thousandfold, the rain-like blows of many electrons on the 

 plate of a tube have been heard, making a sound like a 

 great waterfall in the distance. This strange effect was 

 achieved in America by Dr A. W. Hall and Dr N. H. 

 Williams, of Michigan University. 



Sir Ernest has widespread interests, as his speeches and 



