n8 Miracles Ahead! 



step it up to voltages where it could be pushed through long 

 transmission lines without serious losses. 



"The thyratron, purely an electronic device, promises, for 

 the first time in the history of the power industry, high- 

 voltage direct current. A great and devastating revolution is 

 threatened in the transmission of power. It will, however, be 

 a constructive revolution and one of great benefit to both the 

 manufacturer and the user of electric power. 



"Because of line losses that do not occur when high-voltage 

 direct current is used and because of the great difficulty of 

 insulating high-voltage alternating-current lines, an alternat- 

 ing-current transmission line designed for 230,000 volts would 

 carry no less than 300,000 volts of direct current. But that is 

 not all the story; the actual power carried by the direct cur- 

 rent would be from two to four times greater than the power 

 carried by the alternating current. 



"When it is estimated that $1,500,000,000 has been invested 

 in transmission lines, we begin to get some idea of the prodi- 

 gious possibilities of this thyratron. If we are able to transmit 

 only twice the amount of current over our existing lines, pub- 

 lic utility assets will be created out of thin air." 



That is but one example of the dramatic possibilities of 

 vacuum tubes in industry. Even today they are used in more 

 than one thousand unexpected ways. Tomorrow, who knows? 



While the thyratron is used as a rectifier, in the manner of 

 a diode, the thyratron is a triode, or three-element tube. This 

 third element, the "grid," makes possible the instantaneous 

 control of power by the tube. 



James Stokley, of the General Electric Research Laborato- 

 ries, gives this exceptionally good explanation of the action of 

 the grid. 1 



"This was the invention of another American, Lee de For- 

 est, in 1907. Between filament and plate he inserted a small 



1 Stokley, James, Science Remakes Our World. New York, Ives Wash- 

 burn, 1942. 



