National Geographic : 1938 Jul
AT FIVE MILES ABOVE THE NATION'S CAPITAL, INFRARED FILM "SEES"' FAR Major Albert W. Stevens, of the United States Army Air Corps, made five flights from Wright Field, in Day ton, Ohio, before he found a completely cloudless day in the Washington region. Infrared photography from high altitudes, with a range much greater than that of the human eye, is successful today largely because of more than a decade of experiment by the U. S . Army personnel. On the ground, the temperature on this October day was 75 degrees; at 26,000 feet above the little town of Burke, Virginia, 12 miles west of Alexandria, it was 30 below zero when the picture was taken with a 1/0 second exposure. Looking northeastward from Virginia across the District and Maryland, the camera sees into Pennsylvania, Delaware, and New Jersey. The horizon is more than 200 miles away.