National Geographic : 2010 Dec
FLASHBACK NATIONAL GEOGRAPHIC ISSN 0027 9358 PUBLISHED MONTHLY BY THE NATIONAL GEOGRAPHIC SOCIETY, 1145 17TH ST. NW, WASHINGTON, DC 20036. ONE YEAR MEMBERSHIP: $34.00 U.S. DELIVERY, $38.00 TO CANADA, $49.50 TO INTERNATIONAL ADDRESSES. SINGLE ISSUE: $7.00 U.S. DELIVERY, $10.00 CANADA, $15.00 INTERNATIONAL. ALL PRICES IN U.S. FUNDS; INCLUDES SHIPPING AND HAN DLING. PERIODICALS POSTAGE PAID AT WASHINGTON, DC, AND ADDITIONAL MAILING OFFICES. POSTMASTER: SEND ADDRESS CHANGES TO NATIONAL GEOGRAPHIC, PO BOX 63002, TAMPA, FL 33663. IN CANADA, AGREEMENT NUMBER 40063649, RETURN UNDELIVERABLE ADDRESSES TO NATIONAL GEOGRAPHIC, PO BOX 4412 STN. A, TORONTO, ONTARIO M5W 3W2. UNITED KINGDOM NEWSSTAND PRICE £4.99. REPR. EN FRANCE: EMD FRANCE SA, BP 1029, 59011 LILLE CEDEX; TEL. 320.300.302; CPPAP 0710U89037; DIRECTEUR PUBLICATION: D. TASSINARI DIR. RESP. ITALY; RAPP IMD SRL, VIA G. DA VELATE 11, 20162 MILANO; AUT. TRIB. MI 258 26/5/84 POSTE ITALIANE SPA; SPED. ABB. POST. DL 353/2003 CONV L.27/02/2004 N.46 ART 1 C. 1 DCB MILANO STAMPA QUAD/GRAPHICS, MARTINSBURG, WV 25401. MEMBERS: IF THE POSTAL SERVICE ALERTS US THAT YOUR MAGAZINE IS UNDELIVERABLE, WE HAVE NO FURTHER OBLIGATION UNLESS WE RECEIVE A CORRECTED ADDRESS WITHIN TWO YEARS. PHOTO: ROBERT F. SISSON, NATIONAL GEOGRAPHIC STOCK The Sound and the Furry "Too shrill for the human ear to hear," a little bat's voice turned visible when the animal was placed before a microphone hooked up to a cathode-ray oscilloscope. "The streaks above and below the central luminous spot are the visual representation of the creature's cries, which have a frequency of 50,000 cycles per second---some 30,000 above the maximum range audible to man, " noted this photograph's caption in "Mystery Mammals of the Twilight, " published in the July 1946 Geographic. "Such experiments ...first proved that bats 'see with their ears,' guiding their flight by the echoes of their cries." ---Margaret G. Zackowitz O Flashback Archive Find all the photos at ngm.com.