42 THE NEW WORLD OF SCIENCE 



very high frequency was perfected too late to be of use, but it 

 represents a war development of extraordinary interest. The 

 credit for it is due primarily to Dr. Langevin of Paris, though 

 the New York and San Pedro groups of American physicists 

 did excellent work in the same direction following Langevin's 

 lead. Other anti-submarine devices in considerable number 

 were developed and effectively used, but these two are in most 

 respects the most notable. 



But it has not merely been in sound-ranging and in submarine 

 detection that the war has demonstrated the capabilities of 

 science. Every single phase of our war activities has told the 

 same story. Turn, for example, to the development of new 

 scientific devices for use with aircraft. How was that 

 handled? The Science and Research Division of the Signal 

 Corps, organized through the cooperation of the Signal Corps 

 and the National Research Council, and later transferred to 

 the Bureau of Aircraft Production, had a group of as many as 

 fifty highly trained men, physicists and engineers, who were 

 working in Washington and in the experimental station at 

 Langley Field, twelve hours a day, seven days a week, on 

 aviation problems one group on improvements in accurate 

 bomb dropping, another on improvements in airplane 

 photography, another on the mapping of the highways of the 

 upper air in aid of aviation, another upon balloon problems, 

 such as the development of non-inflammable balloons, another 

 on aviation instruments, compasses, speed meters, etc., and 

 producing the best there are in the world, and finally a group 

 on new sensitizing dyes for long wave-length photography, etc. 

 Let me select for special comment the most important physical 

 principles which have just now for the first time found large 

 and effective application in war. I shall classify these under 

 six heads. 



The first two of these are (i) the principle of binaural audi- 

 tion and (2) the principle of sound-ranging (locating the posi- 

 tion of a gun by plotting the sound wave emanating from it). 

 These two share the honor of having proved themselves the 



