CHAPTER VI.
THE WALL CORNICE
§ I. We have lastly to consider the close of the wall’s existence, or its cornice. It was above stated, that a cornice has one of two offices: if the wall have nothing to carry, the cornice is its roof, and defends it from the weather; if there is weight to be carried above the wall, the cornice is its hand, and is expanded to carry the said weight.
There are several ways of roofing or protecting independent walls, according to the means nearest at hand: sometimes the wall has a true roof all to itself; sometimes it terminates in a small gabled ridge, made of bricks set slanting, as constantly in the suburbs of London; or of hewn stone, in stronger work; or in a single sloping face, inclined to the outside. We need not trouble ourselves at present about these small roofings, which are merely the diminutions of large ones; but we must examine the important and constant member of the wall structure, which prepares it either for these small roofs or for weights above, and is its true cornice.
§ II. The reader will, perhaps, as heretofore, be kind enough to think for himself, how, having carried up his wall veil as high as it may be needed, he will set about protecting it from weather, or preparing it for weight. Let him imagine the top of the unfinished wall, as it would be seen from above with all the joints, perhaps uncemented, or imperfectly filled up with cement, open to the sky; and small broken materials filling gaps between large ones, and leaving cavities ready for the rain to soak into, and loosen and dissolve the cement, and split, as it froze, the whole to pieces. I am much mistaken if his first impulse would not be to take a great flat stone and lay it on the top; or rather a series of such, side by side, projecting well over the edge of the wall veil. If, also, he proposed to lay a weight (as, for instance, the end of a beam) on the wall, he would feel at once that the pressure of this beam on, or rather among, the small stones of the wall veil, might very possibly dislodge or disarrange some of them; and the first impulse would be, in this case, also to lay a large flat stone on the top of all to receive the beam, or any other weight, and distribute it equally among the small stones below, as at a, Fig. IV.
Fig. IV.
§ III. We must therefore have our flat stone in either case; and let b, Fig. IV., be the section or side of it, as it is set across the wall. Now, evidently, if by any chance this weight happen to be thrown more on the edges of this stone than the centre, there will be a chance of these edges breaking off. Had we not better, therefore, put another stone, sloped off to the wall, beneath the projecting one, as at c. But now our cornice looks somewhat too heavy for the wall; and as the upper stone is evidently of needless thickness, we will thin it somewhat, and we have the form d. Now observe: the lower or bevelled stone here at d corresponds to d in the base (Fig. II., page 59). That was the foot of the wall; this is its hand. And the top stone here, which is a constant member of cornices, corresponds to the under stone c, in Fig. II., which is a constant member of bases. The reader has no idea at present of the enormous importance of these members; but as we shall have to refer to them perpetually, I must ask him to compare them, and fix their relations well in his mind: and, for convenience, I shall call the bevelled or sloping stone, X, and the upright edged stone, Y. The reader may remember easily which is which; for X is an intersection of two slopes, and may therefore properly mean either of the two sloping stones; and Y is a figure with a perpendicular line and two slopes, and may therefore fitly stand for the upright stone in relation to each of the sloping ones; and as we shall have to say much more about cornices than about bases, let X and Y stand for the stones of the cornice, and Xb and Yb for those of the base, when distinction is needed.
§ IV. Now the form at d, Fig. IV., is the great root and primal type of all cornices whatsoever. In order to see what forms may be developed from it, let us take its profile a little larger—a, Fig. V., with X and Y duly marked. Now this form, being the root of all cornices, may either have to finish the wall and so keep off rain; or, as so often stated, to carry weight. If the former, it is evident that, in its present profile, the rain will run back down the slope of X; and if the latter, that the sharp angle or edge of X, at k, may be a little too weak for its work, and run a chance of giving way. To avoid the evil in the first case, suppose we hollow the slope of X inwards, as at b; and to avoid it in the second case, suppose we strengthen X by letting it bulge outwards, as at c.
Fig. V.
§ V. These (b and c) are the profiles of two vast families of cornices, springing from the same root, which, with a third arising from their combination (owing its origin to æsthetic considerations, and inclining sometimes to the one, sometimes to the other), have been employed, each on its third part of the architecture of the whole world throughout all ages, and must continue to be so employed through such time as is yet to come. We do not at present speak of the third or combined group; but the relation of the two main branches to each other, and to the line of origin, is given at e, Fig. V.; where the dotted lines are the representatives of the two families, and the straight line of the root. The slope of this right line, as well as the nature of the curves, here drawn as segments of circles, we leave undetermined: the slope, as well as the proportion of the depths of X and Y to each other, vary according to the weight to be carried, the strength of the stone, the size of the cornice, and a thousand other accidents; and the nature of the curves according to æsthetic laws. It is in these infinite fields that the invention of the architect is permitted to expatiate, but not in the alteration of primitive forms.
§ VI. But to proceed. It will doubtless appear to the reader, that, even allowing for some of these permissible variations in the curve or slope of X, neither the form at b, nor any approximation to that form, would be sufficiently undercut to keep the rain from running back upon it. This is true; but we have to consider that the cornice, as the close of the wall’s life, is of all its features that which is best fitted for honor and ornament. It has been esteemed so by almost all builders, and has been lavishly decorated in modes hereafter to be considered. But it is evident that, as it is high above the eye, the fittest place to receive the decoration is the slope of X, which is inclined towards the spectator; and if we cut away or hollow out this slope more than we have done at b, all decoration will be hid in the shadow. If, therefore, the climate be fine, and rain of long continuance not to be dreaded, we shall not hollow the stone X further, adopting the curve at b merely as the most protective in our power. But if the climate be one in which rain is frequent and dangerous, as in alternations with frost, we may be compelled to consider the cornice in a character distinctly protective, and to hollow out X farther, so as to enable it thoroughly to accomplish its purpose. A cornice thus treated loses its character as the crown or honor of the wall, takes the office of its protector, and is called a DRIPSTONE. The dripstone is naturally the attribute of Northern buildings, and therefore especially of Gothic architecture; the true cornice is the attribute of Southern buildings, and therefore of Greek and Italian architecture; and it is one of their peculiar beauties, and eminent features of superiority.
§ VII. Before passing to the dripstone, however, let us examine a little farther into the nature of the true cornice. We cannot, indeed, render either of the forms b or c, Fig. V., perfectly protective from rain, but we can help them a little in their duty by a slight advance of their upper ledge. This, with the form b, we can best manage by cutting off the sharp upper point of its curve, which is evidently weak and useless; and we shall have the form f. By a slight advance of the upper stone c, we shall have the parallel form g.
These two cornices, f and g, are characteristic of early Byzantine work, and are found on all the most lovely examples of it in Venice. The type a is rarer, but occurs pure in the most exquisite piece of composition in Venice—the northern portico of St. Mark’s; and will be given in due time.
§ VIII. Now the reader has doubtless noticed that these forms of cornice result, from considerations of fitness and necessity, far more neatly and decisively than the forms of the base, which we left only very generally determined. The reason is, that there are many ways of building foundations, and many good ways, dependent upon the peculiar accidents of the ground and nature of accessible materials. There is also room to spare in width, and a chance of a part of the arrangement being concealed by the ground, so as to modify height. But we have no room to spare in width on the top of a wall, and all that we do must be thoroughly visible; and we can but have to deal with bricks, or stones of a certain degree of fineness, and not with mere gravel, or sand, or clay,—so that as the conditions are limited, the forms become determined; and our steps will be more clear and certain the farther we advance. The sources of a river are usually half lost among moss and pebbles, and its first movements doubtful in direction; but, as the current gathers force, its banks are determined, and its branches are numbered.
§ IX. So far of the true cornice: we have still to determine the form of the dripstone.
Fig. VI.
We go back to our primal type or root of cornice, a of Fig. V. We take this at a in Fig. VI., and we are to consider it entirely as a protection against rain. Now the only way in which the rain can be kept from running back on the slope of X is by a bold hollowing out of it upwards, b. But clearly, by thus doing, we shall so weaken the projecting part of it that the least shock would break it at the neck, c; we must therefore cut the whole out of one stone, which will give us the form d. That the water may not lodge on the upper ledge of this, we had better round it off; and it will better protect the joint at the bottom of the slope if we let the stone project over it in a roll, cutting the recess deeper above. These two changes are made in e: e is the type of dripstones; the projecting part being, however, more or less rounded into an approximation to the shape of a falcon’s beak, and often reaching it completely. But the essential part of the arrangement is the up and under cutting of the curve. Wherever we find this, we are sure that the climate is wet, or that the builders have been bred in a wet country, and that the rest of the building will be prepared for rough weather. The up cutting of the curve is sometimes all the distinction between the mouldings of far-distant countries and utterly strange nations.
Fig. VII.
Fig. VII. representing a moulding with an outer and inner curve, the latter undercut. Take the outer line, and this moulding is one constant in Venice, in architecture traceable to Arabian types, and chiefly to the early mosques of Cairo. But take the inner line; it is a dripstone at Salisbury. In that narrow interval between the curves there is, when we read it rightly, an expression of another and mightier curve,—the orbed sweep of the earth and sea, between the desert of the Pyramids, and the green and level fields through which the clear streams of Sarum wind so slowly.
Fig. VIII.
And so delicate is the test, that though pure cornices are often found in the north,—borrowed from classical models,—so surely as we find a true dripstone moulding in the South, the influence of Northern builders has been at work; and this will be one of the principal evidences which I shall use in detecting Lombard influence on Arab work; for the true Byzantine and Arab mouldings are all open to the sky and light, but the Lombards brought with them from the North the fear of rain, and in all the Lombardic Gothic we instantly recognize the shadowy dripstone: a, Fig. VIII., is from a noble fragment at Milan, in the Piazza dei Mercanti; b, from the Broletto of Como. Compare them with c and d; both from Salisbury; e and f from Lisieux, Normandy; g and h from Wenlock Abbey, Shropshire.
§ X. The reader is now master of all that he need know about the construction of the general wall cornice, fitted either to become a crown of the wall, or to carry weight above. If, however, the weight above become considerable, it may be necessary to support the cornice at intervals with brackets; especially if it be required to project far, as well as to carry weight; as, for instance, if there be a gallery on top of the wall. This kind of bracket-cornice, deep or shallow, forms a separate family, essentially connected with roofs and galleries; for if there be no superincumbent weight, it is evidently absurd to put brackets to a plain cornice or dripstone (though this is sometimes done in carrying out a style); so that, as soon as we see a bracket put to a cornice, it implies, or should imply, that there is a roof or gallery above it. Hence this family of cornices I shall consider in connection with roofing, calling them “roof cornices,” while what we have hitherto examined are proper “wall cornices.” The roof cornice and wall cornice are therefore treated in division D.
We are not, however, as yet nearly ready for our roof. We have only obtained that which was to be the object of our first division (A); we have got, that is to say, a general idea of a wall and of the three essential parts of a wall; and we have next, it will be remembered, to get an idea of a pier and the essential parts of a pier, which were to be the subjects of our second division (B).
CHAPTER VII.
THE PIER BASE
§ I. In § III. of Chap. III., it was stated that when a wall had to sustain an addition of vertical pressure, it was first fitted to sustain it by some addition to its own thickness; but if the pressure became very great, by being gathered up into Piers.
I must first make the reader understand what I mean by a wall’s being gathered up. Take a piece of tolerably thick drawing-paper, or thin Bristol board, five or six inches square. Set it on its edge on the table, and put a small octavo book on the edge or top of it, and it will bend instantly. Tear it into four strips all across, and roll up each strip tightly. Set these rolls on end on the table, and they will carry the small octavo perfectly well. Now the thickness or substance of the paper employed to carry the weight is exactly the same as it was before, only it is differently arranged, that is to say, “gathered up.”35 If therefore a wall be gathered up like the Bristol board, it will bear greater weight than it would if it remained a wall veil. The sticks into which you gather it are called Piers. A pier is a coagulated wall.
§ II. Now you cannot quite treat the wall as you did the Bristol board, and twist it up at once; but let us see how you can treat it. Let A, Fig. IX., be the plan of a wall which you have made inconveniently and expensively thick, and which still appears to be slightly too weak for what it must carry: divide it, as at B, into equal spaces, a, b, a, b, &c. Cut out a thin slice of it at every a on each side, and put the slices you cut out on at every b on each side, and you will have the plan at B, with exactly the same quantity of bricks. But your wall is now so much concentrated, that, if it was only slightly too weak before, it will be stronger now than it need be; so you may spare some of your space as well as your bricks by cutting off the corners of the thicker parts, as suppose c, c, c, c, at C: and you have now a series of square piers connected by a wall veil, which, on less space and with less materials, will do the work of the wall at A perfectly well.
Fig. IX.
§ III. I do not say how much may be cut away in the corners c, c,—that is a mathematical question with which we need not trouble ourselves: all that we need know is, that out of every slice we take from the “b‘s” and put on at the “a’s,” we may keep a certain percentage of room and bricks, until, supposing that we do not want the wall veil for its own sake, this latter is thinned entirely away, like the girdle of the Lady of Avenel, and finally breaks, and we have nothing but a row of square piers, D.
§ IV. But have we yet arrived at the form which will spare most room, and use fewest materials. No; and to get farther we must apply the general principle to our wall, which is equally true in morals and mathematics, that the strength of materials, or of men, or of minds, is always most available when it is applied as closely as possible to a single point.
Let the point to which we wish the strength of our square piers to be applied, be chosen. Then we shall of course put them directly under it, and the point will be in their centre. But now some of their materials are not so near or close to this point as others. Those at the corners are farther off than the rest.
Now, if every particle of the pier be brought as near as possible to the centre of it, the form it assumes is the circle.
The circle must be, therefore, the best possible form of plan for a pier, from the beginning of time to the end of it. A circular pier is called a pillar or column, and all good architecture adapted to vertical support is made up of pillars, has always been so, and must ever be so, as long as the laws of the universe hold.
The final condition is represented at E, in its relation to that at D. It will be observed that though each circle projects a little beyond the side of the square out of which it is formed, the space cut off at the angles is greater than that added at the sides; for, having our materials in a more concentrated arrangement, we can afford to part with some of them in this last transformation, as in all the rest.
§ V. And now, what have the base and the cornice of the wall been doing while we have been cutting the veil to pieces and gathering it together?
The base is also cut to pieces, gathered together, and becomes the base of the column.
The cornice is cut to pieces, gathered together, and becomes the capital of the column. Do not be alarmed at the new word, it does not mean a new thing; a capital is only the cornice of a column, and you may, if you like, call a cornice the capital of a wall.
We have now, therefore, to examine these three concentrated forms of the base, veil, and cornice: first, the concentrated base, still called the Base of the column; then the concentrated veil, called the Shaft of the column; then the concentrated cornice, called the Capital of the column.
And first the Base:—
Fig. X.
§ VI. Look back to the main type, Fig. II., page 55, and apply its profiles in due proportion to the feet of the pillars at E in Fig. IX. p. 72: If each step in Fig. II. were gathered accurately, the projection of the entire circular base would be less in proportion to its height than it is in Fig. II.; but the approximation to the result in Fig. X. is quite accurate enough for our purposes. (I pray the reader to observe that I have not made the smallest change, except this necessary expression of a reduction in diameter, in Fig. II. as it is applied in Fig. X., only I have not drawn the joints of the stones because these would confuse the outlines of the bases; and I have not represented the rounding of the shafts, because it does not bear at present on the argument.) Now it would hardly be convenient, if we had to pass between the pillars, to have to squeeze ourselves through one of those angular gaps or brêches de Roland in Fig. X. Our first impulse would be to cut them open; but we cannot do this, or our piers are unsafe. We have but one other resource, to fill them up until we have a floor wide enough to let us pass easily: this we may perhaps obtain at the first ledge, we are nearly sure to get it at the second, and we may then obtain access to the raised interval, either by raising the earth over the lower courses of foundation, or by steps round the entire building.
Fig. XI. is the arrangement of Fig. X. so treated.
Fig. XI.
§ VII. But suppose the pillars are so vast that the lowest chink in Fig. X. would be quite wide enough to let us pass through it. Is there then any reason for filling it up? Yes. It will be remembered that in Chap. IV. § VIII. the chief reason for the wide foundation of the wall was stated to be “that it might equalise its pressure over a large surface;” but when the foundation is cut to pieces as in Fig. X., the pressure is thrown on a succession of narrowed and detached spaces of that surface. If the ground is in some places more disposed to yield than in others, the piers in those places will sink more than the rest, and this distortion of the system will be probably of more importance in pillars than in a wall, because the adjustment of the weight above is more delicate; we thus actually want the weight of the stones between the pillars, in order that the whole foundation may be bonded into one, and sink together if it sink at all: and the more massy the pillars, the more we shall need to fill the intervals of their foundations. In the best form of Greek architecture, the intervals are filled up to the root of the shaft, and the columns have no independent base; they stand on the even floor of their foundation.
§ VIII. Such a structure is not only admissible, but, when the column is of great thickness in proportion to its height, and the sufficient firmness, either of the ground or prepared floor, is evident, it is the best of all, having a strange dignity in its excessive simplicity. It is, or ought to be, connected in our minds with the deep meaning of primeval memorial. “And Jacob took the stone that he had put for his pillow, and set it up for a pillar.” I do not fancy that he put a base for it first. If you try to put a base to the rock-piers of Stonehenge, you will hardly find them improved; and two of the most perfect buildings in the world, the Parthenon and Ducal palace of Venice, have no bases to their pillars: the latter has them, indeed, to its upper arcade shafts; and had once, it is said, a continuous raised base for its lower ones: but successive elevations of St. Mark’s Place have covered this base, and parts of the shafts themselves, with an inundation of paving stones; and yet the building is, I doubt not, as grand as ever. Finally, the two most noble pillars in Venice, those brought from Acre, stand on the smooth marble surface of the Piazzetta, with no independent bases whatever. They are rather broken away beneath, so that you may look under parts of them, and stand (not quite erect, but leaning somewhat) safe by their own massy weight. Nor could any bases possibly be devised that would not spoil them.
§ IX. But it is otherwise if the pillar be so slender as to look doubtfully balanced. It would indeed stand quite as safely without an independent base as it would with one (at least, unless the base be in the form of a socket). But it will not appear so safe to the eye. And here for the first time, I have to express and apply a principle, which I believe the reader will at once grant,—that features necessary to express security to the imagination, are often as essential parts of good architecture as those required for security itself. It was said that the wall base was the foot or paw of the wall. Exactly in the same way, and with clearer analogy, the pier base is the foot or paw of the pier. Let us, then, take a hint from nature. A foot has two offices, to bear up, and to hold firm. As far as it has to bear up, it is uncloven, with slight projection,—look at an elephant’s (the Doric base of animality);36 but as far as it has to hold firm, it is divided and clawed, with wide projections,—look at an eagle’s.
§ X. Now observe. In proportion to the massiness of the column, we require its foot to express merely the power of bearing up; in fact, it can do without a foot, like the Squire in Chevy Chase, if the ground only be hard enough. But if the column be slender, and look as if it might lose its balance, we require it to look as if it had hold of the ground, or the ground hold of it, it does not matter which,—some expression of claw, prop, or socket. Now let us go back to Fig. XI., and take up one of the bases there, in the state in which we left it. We may leave out the two lower steps (with which we have nothing more to do, as they have become the united floor or foundation of the whole), and, for the sake of greater clearness, I shall not draw the bricks in the shaft, nor the flat stone which carries them, though the reader is to suppose them remaining as drawn in Fig. XI.; but I shall only draw the shaft and its two essential members of base, Xb and Yb, as explained at p. 65, above: and now, expressing the rounding of these numbers on a somewhat larger scale, we have the profile a, Fig. XII.; b, the perspective appearance of such a base seen from above; and c, the plan of it.
§ XI. Now I am quite sure the reader is not satisfied of the stability of this form as it is seen at b; nor would he ever be so with the main contour of a circular base. Observe, we have taken some trouble to reduce the member Yb into this round form, and all that we have gained by so doing, is this unsatisfactory and unstable look of the base; of which the chief reason is, that a circle, unless enclosed by right lines, has never an appearance of fixture, or definite place,37—we suspect it of motion, like an orb of heaven; and the second is, that the whole base, considered as the foot of the shaft, has no grasp nor hold: it is a club-foot, and looks too blunt for the limb,—it wants at least expansion, if not division.
Fig. XII.
§ XII. Suppose, then, instead of taking so much trouble with the member Yb, we save time and labor, and leave it a square block. Xb must, however, evidently follow the pillar, as its condition is that it slope to the very base of the wall veil, and of whatever the wall veil becomes. So the corners of Yb will project beyond the circle of Xb, and we shall have (Fig. XII.) the profile d, the perspective appearance e, and the plan f. I am quite sure the reader likes e much better than he did b. The circle is now placed, and we are not afraid of its rolling away. The foot has greater expansion, and we have saved labor besides, with little loss of space, for the interval between the bases is just as great as it was before,—we have only filled up the corners of the squares.
But is it not possible to mend the form still further? There is surely still an appearance of separation between Xb and Yb, as if the one might slip off the other. The foot is expanded enough; but it needs some expression of grasp as well. It has no toes. Suppose we were to put a spur or prop to Xb at each corner, so as to hold it fast in the centre of Yb. We will do this in the simplest possible form. We will have the spur, or small buttress, sloping straight from the corner of Yb up to the top of Xb, and as seen from above, of the shape of a triangle. Applying such spurs in Fig. XII., we have the diagonal profile at g, the perspective h, and the plan i.
§ XIII. I am quite sure the reader likes this last base the best, and feels as if it were the firmest. But he must carefully distinguish between this feeling or imagination of the eye, and the real stability of the structure. That this real stability has been slightly increased by the changes between b and h, in Fig. XII., is true. There is in the base h somewhat less chance of accidental dislocation, and somewhat greater solidity and weight. But this very slight gain of security is of no importance whatever when compared with the general requirements of the structure. The pillar must be perfectly secure, and more than secure, with the base b, or the building will be unsafe, whatever other base you put to the pillar. The changes are made, not for the sake of the almost inappreciable increase of security they involve, but in order to convince the eye of the real security which the base b appears to compromise. This is especially the case with regard to the props or spurs, which are absolutely useless in reality, but are of the highest importance as an expression of safety. And this will farther appear when we observe that they have been above quite arbitrarily supposed to be of a triangular form. Why triangular? Why should not the spur be made wider and stronger, so as to occupy the whole width of the angle of the square, and to become a complete expansion of Xb to the edge of the square? Simply because, whatever its width, it has, in reality, no supporting power whatever; and the expression of support is greatest where it assumes a form approximating to that of the spur or claw of an animal. We shall, however, find hereafter, that it ought indeed to be much wider than it is in Fig. XII., where it is narrowed in order to make its structure clearly intelligible.
§ XIV. If the reader chooses to consider this spur as an æsthetic feature altogether, he is at liberty to do so, and to transfer what we have here said of it to the beginning of Chap. XXV. I think that its true place is here, as an expression of safety, and not a means of beauty; but I will assume only, as established, the form e of Fig. XII., which is absolutely, as a construction, easier, stronger, and more perfect than b. A word or two now of its materials. The wall base, it will be remembered, was built of stones more neatly cut as they were higher in place; and the members, Y and X, of the pier base, were the highest members of the wall base gathered. But, exactly in proportion to this gathering or concentration in form, should, if possible, be the gathering or concentration of substance. For as the whole weight of the building is now to rest upon few and limited spaces, it is of the greater importance that it should be there received by solid masonry. Xb and Yb are therefore, if possible, to be each of a single stone; or, when the shaft is small, both cut out of one block, and especially if spurs are to be added to Xb. The reader must not be angry with me for stating things so self-evident, for these are all necessary steps in the chain of argument which I must not break. Even this change from detached stones to a single block is not without significance; for it is part of the real service and value of the member Yb to provide for the reception of the shaft a surface free from joints; and the eye always conceives it as a firm covering over all inequalities or fissures in the smaller masonry of the floor.