n6 Miracles Ahead! 



leaps and bounds. Mass production of other equipment has 

 owed its tremendous growth to electronic devices. Radio fre- 

 quency has cut the drying time of one type of plywood from 

 three days to three minutes. Electronic eyes study a machine 

 whirling at seven thousand revolutions per minute as though 

 it were standing still, diagnosing the most minute flaw in its 

 moving parts before that flaw becomes serious enough to 

 cause a breakdown. Electronic research goes on apace. In 

 November, 1942, the R.C.A. Radio-Electronic Laboratories 

 were dedicated. Housed within a building almost five hundred 

 feet long are one hundred and fifty laboratories where the 

 secret weapons of today are being developed to win the war, 

 and where new electronic wonders will become handmaidens 

 of tomorrow's miracle world. 



Edison Discovered the Secret 



As far back as 1883 Thomas Edison discovered the secret 

 which is the basis of electronics today. He was experiment- 

 ing with his new invention, the electric-light bulb. He found 

 that when he sealed a metal plate into the bulb, and con- 

 nected that plate to the positive charge of a battery, current 

 flowed from the heated filament of his light bulb to the posi- 

 tively charged plate. Current was flowing across empty space! 

 Edison patented his discovery, and it has since been known 

 as the "Edison effect." But the patent ran out before Edison 

 attempted to develop it further. 



Twenty-one years later, Professor J. A. Fleming developed 

 this Edison effect into a vacuum tube which was called the 

 "Fleming valve," and put this effect of current flow by "ther- 

 mionic emission" to work. Edison had already stumbled on 

 the fact that, if a substance is sealed in a vacuum tube and 

 heated, electrons will be emitted from it, or evaporated, just 

 as we can evaporate a pan of water by applying heat and 

 boiling it rapidly. 



