Effects of moving loads on highway bridges
A 1909 civil engineering thesis by Jesse Jacobsen Wallendom and Thomas Douglas Mylrea at the University of Illinois, recording deflection tests of highway bridges under moving loads for faculty examiners and other engineers. The plates are photographic reductions of instrument traces: long straight baselines in blue and red ink running across tinted paper, broken by bursts of dense vibration, each labelled with a hand-lettered test number, giving designers ready-made seismograph-like line textures and numbered rule systems.
