OCR Text |
Show I 'Tin Ear' TROY, IV. Y. Dr. DonaW A. Wilbur of Rensselaer Polytechnic Poly-technic institute is shown testing test-ing a sound detector hastily constructed in the institute's physics laboratory to determine deter-mine how effectively such cheaply built devices might be adopted throughout the country by air raid spotters. A few boards, a phonograph horn, a microphone and a battery-operated amplifier and ear phones are the ingredients ingredi-ents of the detector that can pick up the sound of bombers five to ten miles distant. |