222 ANNUAL KEPORT SMITHSONIAN INSTITUTION, 19 39 



munication has been accepted by law-enforcement agencies through- 

 out the country is ample proof of its value to such organizations. 

 The ability to transmit to the farthest corners of the State, per- 

 tinent information relative to a crime almost before the perpetrator 

 has completed the act, thereby rendering it extremely difficult, if 

 not impossible, for him to escape, is a development of the utmost 

 importance, particularly in view of the swift modes of transpor- 

 tation available to the criminal of today. In addition to furnishing 

 an unparalleled means of communication the principles of radio 

 have been utilized to throw protecting "fields" about homes or other 

 specific areas, permitting actuation of almost any desired type of 

 alarm upon the entry within the protected area by an intruder. 



It is again to be emphasized that the few examples given above 

 represent only a very small number of the myriad applications 

 through which physical science has been of assistance to law en- 

 forcement. Indeed, reviewing the results which modern scientific 

 methods have brought to crime detection, one is constantly tempted 

 to ask with an earlier school of thought, "What more is there to be 

 discovered?" only to be answered with a new development, star- 

 tling in its implication and promise. 



