National Geographic : 1922 Mar
Photograph by Captain A. W. Stevens LAYING DOWN A POISON POWDER BARRAGE AGAINST CATERPILLARS Flying at the rate of 8o miles an hour, at an altitude of from 20 to 35 feet and on a line parallel with and 53yards tothe windward ofa catalpa grove. A wind, varying from 8 to 11 miles an hour, was blowing in the direction indicated bythe arrow. The grove lies directly ahead of the point of the arrow, and is surrounded on the two sides by fields of growing corn. This, as wellasthe following pictures of the machine in action, was taken from an accompanying plane.