Your New Servants: The Electronic "Watchmen" 1 2 1 



metal objects, as an echo bounces from a wall or a mountain- 

 side. With the first detection devices it was possible only to 

 determine that there was a metal object somewhere within 

 range of the radio waves. Today a Radar unit, trained on an 

 enemy field, can tell the Radar operator the instant planes 

 take off from that field, how far away they are, how many 

 there are, at what altitude they are flying, and at what speed. 

 Thus it is possible for the Radar operators and their assistants 

 to plot the course of the enemy planes and to determine to 

 the split second when they will reach a given point, and the 

 planes of the home defense can keep a very unexpected ren- 

 dezvous with the enemy planes at a point of their choice. 



The principle of Radar detection is likewise in use in direct- 

 ing gunfire. Hanson W. Baldwin, of the New York Times, 

 reports a striking incident of the effectiveness of radio direc- 

 tion of gunfire in a naval battle: 



"Radar enabled one of our modern battleships in a night 

 action in the Solomons to locate, fire at and straddle on the 

 first salvo a Japanese battleship eight miles away. 



"The Japanese ship was never actually seen by our men 

 until after she had been hit and was afire. Radar also played 

 a role in various British naval victories in the Mediterranean. 



"Radar is also of major importance in controlling the fire 

 of antiaircraft guns, and at night has replaced, or supple- 

 mented searchlights." 



It is the history of many scientific developments that their 

 underlying principles are discovered, often simultaneously, in 

 different countries of the world. Thus, while the American 

 scientists were developing our version of Radar, in England 

 a Scot, Robert Alexander (now Sir Robert) Watson- Watt, 

 was developing Great Britain's version of Radar, which was 

 to help win the Battle of Britain. It is known that Axis coun- 

 tries likewise have their version of Radar. Therefore the race 

 in detection is a race to develop an instrument increasingly 

 more effective, with a longer range and a more accurate deter- 



