50, 100 and 150 Years Ago; August 2000; Scientific American Magazine; by Staff Editor; 1 Page(s)

WORLD FOOD-"The food problem confronts the world with two dangers. One is the political danger of hunger. A lifetime of malnutrition and hunger is the lot of two thirds of mankind. Yet in the midst of this dire need there remains the economic threat of the food surpluses generated by modern technologies. The abundant food output of the U.S. already has begun to undermine its prosperity. A World Food Board, as an agency of the U.N., would be responsible for maintenance of stable world prices, and would arrange for disposal of surpluses.-John Boyd-Orr, winner of the Nobel Peace Prize in 1949" [Editors' note: The World Food Board was never created.]

ULTRASONIC NAVIGATION-"Photographs of the wave-form of bats' ultrasonic sounds, as seen on the cathode-ray oscilloscope, show that a typical ultrasonic cry lasts only for about one five-hundredth of a second. An audible sound of this extreme brevity is heard as a sharp click. The frequency always seems to drop at least an octave from the beginning to the end of the pulse. Observations show that bats can use pulses of ultrasonic sound to detect objects as close as six inches. Under these conditions an echo will return to the bat's ears before the pulse can finish leaving its mouth. It would seem easier for a bat to distinguish between echo and original pulse if the two differed in frequency, as they do."