OF GROINED RIBBED VAULTS.

55

consists in requiring less centering, and originates inthe positiou of the ribs at the springing.

From these beginnings, vaulting began to assumethose practical advantages, which the joint adop-tion of the pointed arch and ribs was calculated toproduce.

Gray, in a letter to Mr. Mason, says, “ Gothicarchitecture, previous to the time of Henry the Third,is of a clumsy and heavy proportion, with a few rudeand awkward ornaments ; then all at once came inthe tall and picked arches, the light clustered columns,the capitals of curling foliage, the fretted tabernaclesand vaultings, and a profusion of statues, &c. thatconstituted the Gothic style ; together with decreas-ing and flying buttresses and pinnacles on the outside.”If the antiquary will not ascribe the ornaments cha-racteristic of the Gothic architecture of the times ofHenry the Third, and succeeding, ages, to the vaultingthe naves of the cathedrals, nor the pointed arch tothe necessity for its production, but only to fortuitouscircumstances, it must be acknowledged, that thecontemporaneous production is remarkable, especiallyas those ornaments and that form are useful only invaulted buildings.

The second step differed from the first, inasmuchas at the vertex of the vault, a continued key-stoneor ridge projects below the surface of the vault, andforms a feature similar to the ribs. But here it wasnecessary, that the ridge should be a stone of greatlength, or having artificially that property, becauseits suspension by a thinner vault than itself would beunsafe, unless assisted by the rib arches over thediagonals, and side, a distance equal to half the width

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