The Wireless Detective 



How transgressors of national and international Radio laws are caught 



Photo. Ceutral X 



A "Radio Detective" which not only picks up passing wireless messages but also 

 determines the direction from which they come and the probable location of the sender 



EVEN in times of peace it is often of 

 importance to locate wireless sending 

 stations. When an amateur's station is 

 transgressing national law, or a spying 

 government's station is transgressing inter- 

 national law, a "radio detective" will be of 

 valuable assistance to our government. 

 But in time of war, an instrument that can 

 not only intercept wireless messages but 

 can also locate the senders, will be of great 

 strategical importance. 



The photograph above shows such an 

 instrument which has been brought out by 

 Frederic Koester, a young experimenter in 

 the United States Bureau of Standards, of 

 the Department of Commerce. The ap-^ 

 paratus picks up the passing radio mes- 

 sages and, at the same time, indicates the 

 direction from which they come. By 

 listening to the same message with two 

 instruments of this kind placed at two 

 different points, the position of the sender 

 may be definitely determined. It is neces- 

 sary only to mark on a map the two posi- 

 tions where the instruments are receiving 

 the message and to draw two straight lines 

 in the directions shown by them. The place 

 where the two lines cross on the map will 

 indicate the desired spot. 



Motion-Pictures Tell South Americans of 

 Our Industrial Development 



TO acquaint South Americans with the 

 industrial development of this country 

 and particularly to educate them in typical 

 American manufacturing processes, wel- 

 fare work in industrial institutions, and 

 other details of economic life, the commer- 

 cial attaches in the Latin-American coun- 

 tries are exhibiting motion pictures in their 

 respective localities. 



The pictures are being given under the 

 auspices of the Bureau of Foreign and 

 Domestic Commerce, but the films are 

 obtained through the Bureau of Commer- 

 cial Economics, an unofficial organization 

 with headquarters in Washington, which 

 has on hand a large number of films showing 

 various phases of American industry. The 

 films which the Bureau thinks most 

 desirable are sent to the commercial 

 attaches. 



In addition to educating the South 

 Americans along American industrial lines, 

 one purpose of sending the films is to 

 stimulate interest in a much more extended 

 campaign by which American manufac- 

 turers may have their films displayed for 

 advertising purposes. 



