Public domain
Washington, D.C. The U.S. Weather Bureau station at the National Airport. Plotting the course of a pilot balloon as it ascends into the atmosphere to determine the velocity and direction of winds above the surface
From the collection of Library of Congress. Free to download, adapt and use — no permission needed.
Credit lineWashington, D.C. The U.S. Weather Bureau station at the National Airport. Plotting the course of a pilot balloon as it ascends into the atmosphere to determine the velocity and direction of winds abov. 1943-01-01. Driscoll, Fred. Farm Security Administration/Office of War Information Collection, Library of Congress. Public domain.