Lateral Failure of Spars
A 1926 NASA technical report on lateral failure of spars, presented as engineering data rather than a book for general readers. The pictures are scatter plots of test results with fitted curves, plotted on gridded graph paper with axes labelled in pounds, inches and span ratios. A designer could take from them only the sparse, pale grid-and-dot visual language of technical charts, useful for minimal data-graphic backgrounds.
