Quaker Guns near Manassas, VA. During the initial stages of the Civil War, before First Manassas (Bull Run), the Confederate forces knew that the Federal troops were watching them from balloons in Alexandria. In order to fool the Federal troops that they were heavier fortified than they really were, they used "Quaker Guns" which were chopped down tree trunks, and painted them black and pretended they were cannon. (Library of Congress photo)
Mike Lynaugh has an interesting collection of Civil War photos that you can view here.
