Rudiments of the art of building : represented in five sections [...] for the use of architects, builders, draghtsmen, machinists, engineers and mechanics (1853)
Bullock, John · New York : Stringer & Townsend · leaf 51
fig.21, whose thickness is one-ninth of its radius, the line of equalhorizontal thrust just touches the extrados at the crown, andthe intrados at the haunches, pointing out the places wherefailure would take place with a less thickness or an unequalload, by the voussoirs turning on their edges.… … they are well lacked up. Pointed arches have a tendency torise at the crown ; and, to prevent this, the cross springersof the ribbed vaults of the middle ages were often made of asemicircular profile, their flatness at the crown being con-cealed by the bosses at their intersections. 70. If the…
Building
Internet Archive · Getty Research Institute · Public Domain Mark 1.0. Free to use for anything.