Forum Thread: Seeking DIY Carbon Microphone Diagram

In the 1940's (1946/1947) Popular Science magazine printed a DIY diagram of a high impedance microphone using an old battery carbon core and a headphone to listen (rather than speakers). It used a simple wood base and was very sensitive; you could hear a cock-a-roach walking on the wood or a fly's buzz if it landed on the base. ANYONE WHO MIGHT HAVE A COLLECTION OF THESE MAGAZINES AND CAN PROVIDE A COPY OF THE DIAGRAM WOULD GREATLY HELP ME WITH MY PROJECT.