Another improvement is that of the diagonal positions given to the plinths of the lateral vaulting shafts in correspondence with the positions of the vaulting capitals. These plinths are thus parallel also with the sides of the great abacus, where it projects to cover the capital of the lower vaulting column; the adjustment of the great abacus to its load is, moreover, as close as possible, and the whole design is both compact and elegant.
FIG. 34.
We may now examine the vaults and vaulting systems of the more advanced Gothic of the first half of the thirteenth century, in which the continuity of members, from the pavement upwards, becomes an unvarying principle. Not that every individual member of the superstructure now has an independent support from the foundation, but there is at least one independent shaft on the ground-story level sustaining each main group above.
From the beginning of the thirteenth century the
