Note 155 — Chapter I · NAVE AND AISLE VAULTS

This was especially important to the Lombard builders, who always preferred the semicircular arch, which could thus be employed for all six ribs of the vault and would cause the crown to be domed up just high enough to permit the construction of the entire vault by means of a simple centering from rib to rib. See Porter, Cons. of Lombard and Gothic Vaults.