MICHAEL PUPIN 187 



tion guide the evolution of the external material world, 

 so creative co-ordination also guides the evolution of 

 the internal world of the human soul, the destiny of 

 human life. 



This is my message from science. 



In my boyhood days I often put two questions to 

 myself. One question was: What is sound? The 

 other: What is light? A search for an answer to 

 these two questions directed my scientific career. 



What is sound? This will prepare us for my an- 

 swer to the second question. 



When the clapper strikes the church bell the bell 

 vibrates and transmits its vibration to the air. The 

 sound waves in the air, spreading out in every direc- 

 tion, reach the listening ear, and convey to the enquir- 

 ing mind of man the following simple story: 



The collision between the clapper and the bell puts 

 energy into the bell, and, feeding upon this energy, the 

 bell becomes a living thing. Its life manifests itself 

 through its vibrations, which are in harmony with its 

 structure. Neither the clapper nor the power which 

 moves it can change the character of these vibrations. 

 They are the result of the elasticity and the destiny of 

 the material of which the bell Is made, and of Its form 

 which the designing Intelligence of the bell-maker 

 gave it. 



But does this story give us a complete description 

 of this familiar Illustration of sound generation, trans- 

 mission, and perception? No, it does not. It says 

 nothing about the message which the bell is conveying 

 to our souls. To get this part of the story we must 

 follow the vibrations In their passage through that 



