National Geographic : 1931 May
THE FIRST PHOTOGRAPH EVER MADE SHOWING LATERALLY THE CURVATURE OFTHE EARTH This unusually interesting photograph of the Andes, including Mount Aconcagua (identified by a white linebelow thebase) atadistance of287miles was made from an airplane, at an elevation of 21,00ooo feet, by Captain Stevens in the course of his camera surveyof theAndean Chain fortheNational Geo graphic Society. The mountain range, which shows clearly in the photograph, could not be seen by the photographer atthetime hemade this picture (see text, page 599). Captain Stevens used a lens of 20-inch focus and an infra-red screen which admits tothe sensitive photographic plate light that is invisible to the eye. The length of the exposure was I/2oth of a second. Almost exactly in the center of therange Mount Tupungato isdistinguished. In the foreground is Villa Mercedes, Argentina.