The matter of Gothic vaulting, with its two weak points, the flying buttress and the false, wooden shelter-roof, is the bete noire of the Beaux Arts.  The duty of defence does not lie on tourists, who are at best hardly able to understand what it matters whether a wall is buttressed without or within, and whether a roof is single or double.  No one objects to the dome of Saint Peter’s.  No one finds fault with the Pont Neuf.  Yet it is true that the Gothic architect showed contempt for facts.  Since he could not support a heavy stone vault on his light columns, he built the lightest possible stone vault and protected it with a wooden shelter-roof which constantly burned.  The lightened vaults were still too heavy for the walls and columns, so the architect threw out buttress beyond buttress resting on separate foundations, exposed to extreme inequalities of weather, and liable to multiplied chances of accident.  The results were certainly disastrous.  The roofs burned; the walls yielded.

Flying buttresses were not a necessity.  The Merveille had none; the Angevin school rather affected to do without them; Albi had none; Assisi stands up independent; but they did give support wherever the architect wanted it and nowhere else; they were probably cheap; and they were graceful.  Whatever expression they gave to a church, at least it was not that of a fortress.  Amiens and Albi are different religions.  The expression concerns us; the construction concerns the Beaux Arts.  The problem of permanent equilibrium which distresses the builder of arches is a technical matter which does not worry, but only amuses, us who sit in the audience and look with delight at the theatrical stage-decoration of the Gothic vault; the astonishing feat of building up a skeleton of stone ribs and vertebrae, on which every pound of weight is adjusted, divided, and carried down from level to level till it touches ground at a distance as a bird would alight.  If any stone in any part, from apex to foundation, weathers or gives way, the whole must yield, and the charge for repairs is probably great, but, on the best building the Ecole des Beaux Arts can build, the charge for repairs is not to be wholly ignored, and at least the Cathedral of Chartres, in spite of terribly hard usage, is as solid to-day as when it was built, and as plumb, without crack or crevice.  Even the towering fragment at Beauvais, poorly built from the first, which has broken down oftener than most Gothic structures, and seems ready to crumble again whenever the wind blows over its windy plains, has managed to survive, after a fashion, six or seven hundred years, which is all that our generation had a right to ask.