e influence of the Gothic
architects. The rule must not of course be pressed far when, in either
school, there has been determined search for every possible variety of
decorative figures; and accidental circumstances may reverse the usual
system in special cases; but the evidence drawn from this character is
collaterally of the highest value, and the tracing it out is a pursuit
of singular interest. Thus, the Pisan Romanesque might in an instant be
pronounced to have been formed under some measure of Lombardic
influence, from the oblique squares set under its arches; and in it we
have the spirit of northern Gothic affecting details of the
southern;--obliquity of square, in magnificently shafted Romanesque. At
Monza, on the other hand, the levelled square is the characteristic
figure of the entire decoration of the facade of the Duomo, eminently
giving it southern character; but the details are derived almost
entirely from the northern Gothic. Here then we have southern spirit and
northern detail. Of the cruciform outline of the load of the shaft, a
still more positive test of northern work, we shall have more to say in
the 28th Chapter; we must at present note certain farther changes in the
form of the grouped shaft, which open the way to every branch of its
endless combinations, southern or northern.

[Illustration: Fig. XVI.]

Sec. XV. 1. If the group at _d3_, Fig. XIV., be taken from under its
loading, and have its centre filled up, it will become a quatrefoil; and
it will represent, in their form of most frequent occurrence, a family
of shafts, whose plans are foiled figures, trefoils, quatrefoils,
cinquefoils, &c.; of which a trefoiled example, from the Frari at
Venice, is the third in Plate II., and a quatrefoil from Salisbury the
eighth. It is rare, however, to find in Gothic architecture shafts of
this family composed of a large number of foils, because multifoiled
shafts are seldom true grouped shafts, but are rather canaliculated
conditions of massy piers. The representatives of this family may be
considered as the quatrefoil on the Gothic side of the Alps; and the
Egyptian multifoiled shaft on the south, approximating to the general
type, _b_, Fig. XVI.

Sec. XVI. Exactly opposed to this great family is that of shafts which
have concave curves instead of convex on each of their sides; but these
are not, properly speaking, grouped shafts at all, and their proper place
is among decorated piers; only they mus