1836 1 162 For arches of thirty feet span, the section of the rib stones may be as in the annexed sketch.
1904 C. F. Mitchell viii. 238 This would be cut out of zinc and used as the templet for cutting the arch rib stones.
2001 (Nexis) 10 Jan. To figure out the different angles that have to be cut in order to seat the next rib stone..to create the arc.