Note 59 — Chapter IV · THE DOME OF ST. PETER’S
Reading edition
It is true that fissures in a properly constructed vault are not necessarily alarming. Any vault may crack from unequal settlement of the supports. Gothic vaults are sometimes slightly ruptured in this way, but they are not thus endangered, because they are effectively buttressed. But fissures in a dome without abutments may be a sign of impending collapse.