No roof is visible from below. The actual roof of oak and lead was so flattened as to be invisible in accordance with the ideas of the architect. "No Roofs almost but Spherick raised to be visible." "The Ancients affected Flatness." "No Roofs can have Dignity enough to appear above a Cornice, but the Circular."[74]
We now come to that peculiarity upon which so much adverse criticism has been bestowed. The usual observer will wonder why there are niches instead of windows in the upper stage, as light is so much needed. On entering the interior he will notice that the height of the aisles does not correspond with the exterior; and on ascending to the Stone Gallery will ascertain that this upper stage of the exterior is not part of the actual wall of the church, which stands back some thirty feet. It is, in fact, a screen or curtain wall; the lower stage alone is the wall of the aisles, and the disfiguring square openings with which the pedestals below the niches are pierced, give light to the passages and galleries between the aisles and the roof. Externally one is supposed to see the wall of the cathedral; in reality one sees the lower story forming the wall, and an upper story in continuation made to look as though the church were immediately behind, but in reality quite disengaged from it. The following is an able specimen of the adverse criticisms that have been directed against this curtain: "It is a mere empty show with nothing behind it, and when once this is known it is impossible to forget it, or to have the same feeling towards the building which a spectator might have, despite its defects of detail, who believed its external mass to represent its interior arrangements."[75] Yet an attentive study of the "Parentalia" enables us to plead a great deal in mitigation. The spectator will notice that there are no substantial buttresses; and the reason is the simple one that Wren held them to be disfigurements. "The Romans always concealed their Butments."[76] "Oblique Positions are Discord to the Eye unless answered in Pairs, as in the Sides of an equicrural Triangle.... Gothick Buttresses are all ill-favoured, and were avoided by the Ancients."[77] Such were the opinions of Wren; but how was he to procure stability? The answer is, by the curtain wall. By its dead weight pressing on the walls of the aisles it renders them stable and immobile, free from all danger of thrust, while it conceals the buttresses which render secure the clerestory stage of the building proper. To paraphrase his own words: "I do not add buttresses, but I build up the wall so high as by the addition of this extra weight, I establish it as firmly as if I had added buttresses."[78] Thus this wall performs a double function: it is a substitute for buttresses in respect to the aisle walls, and a screen for the actual buttresses of the clerestory stage.
Such is the purpose of the upper story. An ingenious critic who did not seem to know this vindicates it on the plea that "uninterrupted altitude of the bulk in the same plane, is absolutely necessary to the substructure of the mighty dome."[79] No doubt the size of the dome requires a proportionate rise in the lower elevations; but the fact remains that the exterior and interior do not correspond. A greater authority than this critic has thus defined good architecture: "The essence of good architecture of any kind is that its constructive system should be put boldly forward, that its decorative system should be such as in no way conceals or masks the construction, but makes the constructive features themselves ornamental."[80] And at his uncle's cathedral of Ely, Wren might have borrowed and worked out an idea which would have silenced all accusation of fraud and deceit. There, in the central part of the choir on the south side, the roof was removed and placed lower down centuries ago, the better to light up certain shrines below. This roof was never restored to its original position; and the upper stage of the wall is pierced with empty windows through which flying-buttresses can now be seen. The effect, though altogether unusual, is far from displeasing; and the spectator who remembers that Wren was perfectly familiar with this building, is led to wonder why he did not by piercing the niches, imitate Ely at St. Paul's.
The Windows, round-headed and without tracery, contrast unfavourably with the Lancet and Decorated. Wren recognised the value of tracery, as is evident from his remarks on Salisbury Cathedral, although he objected to the Perpendicular mullions and transoms.[81] Yet it is difficult to see how he could have devised anything more elaborate or graceful to harmonise. The carving above and below, in the conventional festoons of the day, is almost universally voted as respectable and nothing more. Mr. Ruskin is very severe on these festoons, on the ground that they are tied heavily into a long bunch thickest in the middle, and pinned up by both ends against a dead wall, and contends that the architecture has no business with rich ornament in any place. Yet he admits that the sculpture is as careful and rich as may be; and let any one study, for instance, the window immediately east of the south portico, and particularly below, where the details can be better observed. In spite of a heavy top-coat of smoke, the combination of cherubs, birds, grapes, and foliage is as graceful and artistic as possible; and the work beneath the east end and north transept windows will also well repay careful study. These details are apt to be neglected, possibly because they seem dwarfed by the immense proportions of the building.[82]
The North and South Chapels, as we hear on probably trustworthy authority, were added at the instance of James, Duke of York, who looked forward to the day when the Roman Catholic services would be substituted for the Anglican. Although Stephen is silent as to his grandfather's intentions, there is evidence given by Mr. Longman and Miss Lucy Phillimore to show that Wren tried his best to finish the building without them. Whether seen from the north-east or south-west they interfere with the perspective, and the independence of the lowest stage of the West Towers is completely lost; and curiously enough in this last respect the South-West or Consistory Chapel does very much what St. Gregory's did to the Lollards' Tower in Old St. Paul's.
We now turn to the different parts and members.
North and South Fronts.—These are similar, each part corresponding to each, excepting a slight difference in the steps of the porticoes caused by the ground on the south side sloping towards the Thames; and this uniformity or symmetry is invariably carried out in the different parts wherever feasible. Take the three main windows of the choir aisles on either side, and compare them with the three of the nave aisles on either side between the transepts and the chapels. The windows themselves and their pilasters exactly agree, as do their distances.
Where the uniformity of the fronts is broken by the projecting transepts and chapels, it is broken after one manner, so that when you have seen the north side you have seen the south, excepting for the above-mentioned difference caused by the slope.
The North and South Fronts are approached by flights of steps of black marble. The steps on the north side are twelve in number, and are reached from the whole semi-circle; on the south side they are twenty-five in number, and are reached from the ends, the front having a low wall. Here, the flanking urns on either side afford another instance of the disregard of Wren's wishes. The difference in the number of the steps is caused by the slope towards the Thames, and is interesting as affording an instance of a difference between the two fronts. The Corinthian pillars, of the full diameter of four feet, cleverly support the semi-circular entablature above, which is part of the general entablature continued all round. These porticoes have semi-dome shaped roofs, and are flanked on either side by the windows of the transept aisles. The central windows above the porticoes are slightly larger than the others, and have niches on either side. Above these are triangular pediments, and above these again, and in alignment along the balustrade, are statues of ten of the Apostles—five to each front. The sculpture on the northern pediment depicts the royal arms, with angels bearing palm branches for supporters, and on the southern is a Phœnix with the motto "Resurgam."