Stability of structural members under axial load
A 1937 technical report on the stability of structural members under axial load, produced by NASA's Technical Reports Server for an engineering readership. The three pictures are line diagrams of structural joints with radiating members, external moments and pinned supports, plus a tabulated moment-distribution layout with symbolic expressions. A designer could take from them the clean, schematic vocabulary of early engineering drawing: thin single-weight lines, circled support symbols and curved moment arrows.
