Bridge and tunnel centres
A short engineering manual by John Bach McMaster on timber centering for bridge and tunnel arches, published by D. Van Nostrand in New York in 1875 for builders and civil engineering students. Line engravings show half-elevations of arched wooden falsework — curved ribs, radiating struts, crossed bracing and bolt rows — with small force-triangle diagrams and figure labels usable as technical line ornament.
