We have already noticed the suggestion, in early Gothic or Romanesque, of the dividing up of a pier into a multiple pier, of which each part supports a special member of the superstructure, as indicated in Fig. 90. The Gothic pier, in its development in this respect, affords a striking example of that influence of the superstructure on the plan which has before been referred to. The peculiar manner of building the arch in Gothic work led almost inevitably to this breaking up of the pier into various members. The Roman arch was on its lower surface a simple flat section, the decorative treatment in the way of mouldings being round the circumference, and not on the under side or soffit of the arch, and in early Romanesque work this method was still followed. The mediaeval builders, partly in the first instance because they built with smaller stones, adopted at an early period the plan of building an arch in two or more courses or rings, one below and recessed within the other. As the process of moulding the arch stones became more elaborated, and a larger number of subarches one within another were introduced, this characteristic form of subarches became almost lost to the eye in the multiplicity of the mouldings used. But up to nearly the latest period of Gothic architecture this form may still be traced, if looked for, as the basis of the arrangement of the mouldings, which are all formed by cutting out of so many square sections, recessed one within the other. This will be more fully described in the next lecture. We are now speaking more especially of the pier as affected by this method of building the arches in recessed orders. If we consider the effect of bringing down on the top of a square capital an arch composed of two rings of squared stones, the lower one only half the width (say) of the upper one, it will be apparent that on the square capital the arch stones would leave a portion of the capital at each angle bare, and supporting nothing.4 This looks awkward and illogical, and accordingly the pier is modified so as to suit the shape of the arch.

Figs. 111, 112, 113, and 114, with the plans, B C D, accompanying them, illustrate this development of the pier. Fig. 111 is a simple cylindrical pier with a coarsely formed capital, a kind of reminiscence of the Doric capital, with a plain Romanesque arch starting from it. Fig. 112, shown in plan at B, is the kind of form (varied in different examples) which the pier assumed in Norman and early French work, when the arch had been divided into two recessed orders. The double lines of the arch are seen springing from the cap each way, in the elevation of the pier. If we look at the plan of the pier, we see that, in place of the single cylinder, it is now a square with four smaller half cylinders, one on each face. Of these, those on the right and left of the plan support the subarches of the arcade; the one on the lower side, which we will suppose to be looking toward the nave, supports the shaft which carries the nave vaulting, and which stands on the main capital with a small base of its own, as seen in Fig. 112 - a common feature in early work; and the half column on the upper side of the plan supports the vaulting rib of the aisle.

In Fig. 113 and plan C, which represents a pier of nearly a century later, we see that the pier is broken up by perfectly detached shafts, each with its own capital, and each carrying a group of arch mouldings, which latter have become more elaborated. Fig. 114 and plan D show a late Gothic fourteenth century pier, in which the separate shafts have been abandoned, or rather absorbed into the body of the pier, and the pier is formed of a number of moulded projections, with hollows giving deep shadows between them, and the capitals of the various members run into one another, forming a complete cap round the pier. This pier shows a remarkable contrast in every way to B, yet it is a direct development from the latter. In this late form of pier, it will be observed that the projection, E, which carries the vaulting ribs of the nave, instead of springing from the capital, as in the early example, Fig. 111, springs from the floor, and runs right up past the capital; thus the plan of the vaulting is brought, as it were, down on to the floor, and the connection between the roofing of its building and its plan is as complete as can well be. In Fig. 113 the vaulting shaft is supposed to stop short of the capital and to spring from a corbel in the wall, situated above the limit of the drawing.

This was a common arrangement in the "Early English" and "Early Decorated" periods of Gothic, but it is not so logical and complete, or so satisfactory either to the eye or to the judgment, as starting the vaulting shaft from the floor line. The connection between the roofing and the plan may be further seen by looking at the portion of a mediaeval plan given under Fig. 110, where the dotted lines represent the course of the groin ribs of the roof above. It will be seen how completely these depend upon the plan, so that it is necessary to determine how the roof in a vaulted building is to be arranged before setting out the ground plan.

Thus we see that the Gothic cathedral, entirely different in its form from that of the Greek temple, illustrates, perhaps, even more completely than the Greek style, the same principle of correct and truthful expression of the construction of the building, and that all the main features which give to the style its most striking and picturesque effects are not arbitrarily adopted forms, but are the result of a continuous architectural development based on the development of the construction. The decorative details of the Gothic style, though differing exceedingly from those of the Greek, are, like the latter, conventional adaptations of suggestions from nature; and in this respect again, as well as in the character of the mouldings, we find both sides illustrating the same general principle in the design of ornament, in its relation to position, climate, and material; but this part of the subject will be more fully treated of in the next lecture.