4B HISTORICAL SKETCH OJ? VAULTS.

resistance to the lateral thrust, and consequentlypillars of less substance to support them. M. Souf-flot, in tracing the steps of Gothic architecture in hisscientific Survey of French Churches, and by acquir-ing a knowledge of the Eastern way of vaulting byhemispheres, was enabled to leave in the Church ofSt. Genevieve, now the Pantheon Fra^ais, an exam-ple of lightness in Roman architecture, which beforehis time it was considered not susceptible of. TheVaulting of Notre Dame at Mantes, built by Eudesde Montreuil about the middle of the sixteenth cen-tury, affected Soufflot and Gabriel with such astonish-ment, by the extraordinary hardiness of its construction,that we may believe, that, had they been employed inthe erection, notwithstanding the knowledge whichthey possessed, they also, with the other workmen,would have refused to strike the centre, until theyhad, in the nephew of the architect, a hostage fortheir security.

that vaults should not always have become roofs as well as ceilings,in the cathedrals which are vaulted, A few more conflagrationsand the destruction of an audience may cause theatres to bevaulted. The effects of fire caused the erection of the stonedome of St. Sophia, of Constantinople , and the stone vaulting ofour ecclesiastical buildings.