Elements of the Wing Section Theory and of the Wing Theory
A 1925 aeronautical technical report on airfoil and wing theory, issued through the NASA Technical Reports Server, written for engineers and students of flight. Its two figures are diagrams of fluid flow around a straight line: one shows transverse flow past a moving line with curling streamlines on either side, the other shows circulation flow in closed concentric loops around the line. A designer could take from them the clean, schematic language of streamlines drawn as nested loops and arrows, useful for abstract motion or airflow graphics.

