National Geographic : 1936 Jul
THE NATIONAL GEOGRAPHIC MAGAZINE f'ff? Photograph courtesy M. 1. T. ON THE DOWN STROKE, WING FEATHERS TAKE THIS POSITION TO HELP THE BIRD GAIN ALTITUDE This remarkable high-speed photograph was taken by scientists of the Massachusetts Institute of Technology just after the mourning dove started to fly. Its feathers overlap to prevent air passing through its wings on the down stroke; on the up stroke, they rotate slightly, to let air through and reduce resistance. Photograph by Luis Marden EXACT COPIES OF ANY MODEL ARE SWIFTLY CUT BY THIS WOOD-TURNING MACHINE Operating in the colossal factory of the United Shoe Machinery Corporation at Beverly, near Boston, the machine is now copying a shoemaker's last. At left is the model, at right the crude block. It can also reproduce doll heads, decoy ducks, golf club heads-any simple form in wood (77).