38In saying this, it is assumed that the interval is one which is to be traversed by men; and that a certain relation of the shafts and intervals to the size of the human figure is therefore necessary. When shafts are used in the upper stories of buildings, or on a scale which ignores all relation to the human figure, no such relative limits exist either to slenderness or solidity.39Vide the interesting discussion of this point in Mr. Fergusson’s account of the Temple of Karnak, “Principles of Beauty in Art,” p. 219.40I have assumed that the strength of similar shafts of equal height is as the squares of their diameters; which, though not actually a correct expression, is sufficiently so for all our present purposes.41How far this condition limits the system of shaft grouping we shall see presently. The reader must remember, that we at present reason respecting shafts in the abstract only.42The capitals being formed by the flowers, or by a representation of the bulging out of the reeds at the top, under the weight of the architrave.43I have not been at the pains to draw the complicated piers in this plate with absolute exactitude to the scale of each: they are accurate enough for their purpose: those of them respecting which we shall have farther question will be given on a much larger scale.44The largest I remember support a monument in St. Zeno of Verona; they are of red marble, some ten or twelve feet high.45The effect of this last is given inPlate VI.of the folio series.46The entire development of this cross system in connexion with the vaulting ribs, has been most clearly explained by Professor Willis (Architecture of Mid. Ages, Chap. IV.); and I strongly recommend every reader who is inclined to take pains in the matter, to read that chapter. I have been contented, in my own text, to pursue the abstract idea of shaft form.
38In saying this, it is assumed that the interval is one which is to be traversed by men; and that a certain relation of the shafts and intervals to the size of the human figure is therefore necessary. When shafts are used in the upper stories of buildings, or on a scale which ignores all relation to the human figure, no such relative limits exist either to slenderness or solidity.
39Vide the interesting discussion of this point in Mr. Fergusson’s account of the Temple of Karnak, “Principles of Beauty in Art,” p. 219.
40I have assumed that the strength of similar shafts of equal height is as the squares of their diameters; which, though not actually a correct expression, is sufficiently so for all our present purposes.
41How far this condition limits the system of shaft grouping we shall see presently. The reader must remember, that we at present reason respecting shafts in the abstract only.
42The capitals being formed by the flowers, or by a representation of the bulging out of the reeds at the top, under the weight of the architrave.
43I have not been at the pains to draw the complicated piers in this plate with absolute exactitude to the scale of each: they are accurate enough for their purpose: those of them respecting which we shall have farther question will be given on a much larger scale.
44The largest I remember support a monument in St. Zeno of Verona; they are of red marble, some ten or twelve feet high.
45The effect of this last is given inPlate VI.of the folio series.
46The entire development of this cross system in connexion with the vaulting ribs, has been most clearly explained by Professor Willis (Architecture of Mid. Ages, Chap. IV.); and I strongly recommend every reader who is inclined to take pains in the matter, to read that chapter. I have been contented, in my own text, to pursue the abstract idea of shaft form.
§I.Thereader will remember that inChap. VII.§V.it was said that the cornice of the wall, being cut to pieces and gathered together, formed the capital of the column. We have now to follow it in its transformation.
We must, of course, take our simplest form or root of cornices (a, inFig. V., above). We will take X and Y there, and we must necessarily gather them together as we did Xb and Yb inChap. VII.Look back to the tenth paragraph ofChap. VII., read or glance it over again, substitute X and Y for Xb and Yb, read capital for base, and, as we said that the capital was the hand of the pillar, while the base was its foot, read also fingers for toes; and as you look to the plate,Fig. XII., turn it upside down. Thenh, inFig. XII., becomes now your best general form of block capital, as before of block base.
§II.You will thus have a perfect idea of the analogies between base and capital; our farther inquiry is into their differences. You cannot but have noticed that whenFig. XII.is turned upside down, the square stone (Y) looks too heavy for the supporting stone (X); and that in the profile of cornice (aofFig. V.) the proportions are altogether different. You will feel the fitness of this in an instant when you consider that the principal function of the sloping part inFig. XII.is as a prop to the pillar to keep it fromslipping aside; but the function of the sloping stone in the cornice and capital is tocarry weight above. The thrust of the slope in the one case should therefore be lateral, in the other upwards.
§III.We will, therefore, take the two figures,eandhofFig. XII., and make this change in them as we reverse them,using now the exact profile of the cornicea,—the father of cornices; and we shall thus haveaandb,Fig. XIX.
Both of these are sufficiently ugly, the reader thinks; so do I; but we will mend them before we have done with them: that atais assuredly the ugliest,—like a tile on a flower-pot. It is, nevertheless, the father of capitals; being the simplest condition of the gathered father of cornices. But it is to be observed that the diameter of the shaft here is arbitrarily assumed to be small, in order more clearly to show the general relations of the sloping stone to the shaft and upper stone; and this smallness of the shaft diameter is inconsistent with the serviceableness and beauty of the arrangement ata, if it were to be realised (as we shall see presently); but it is not inconsistent with its central character, as the representative of every species of possible capital; nor is its tile and flower-pot look to be regretted, as it may remind the reader of the reported origin of the Corinthian capital. The stones of the cornice, hitherto called X and Y,receive, now that they form the capital, each a separate name; the sloping stone is called the Bell of the capital, and that laid above it, the Abacus. Abacus means a board or tile: I wish there were an English word for it, but I fear there is no substitution possible, the term having been long fixed, and the reader will find it convenient to familiarise himself with the Latin one.
§IV.The form of base,eofFig. XII., which corresponds to this first form of capital,a,was said to be objectionable only because itlookedinsecure; and the spurs were added as a kind of pledge of stability to the eye. But evidently the projecting corners of the abacus ata,Fig. XIX., areactuallyinsecure; they may break off, if great weight be laid upon them. This is the chief reason of the ugliness of the form; and the spurs inbare now no mere pledges of apparent stability, but have very serious practical use in supporting the angle of the abacus. If, even with the added spur, the support seems insufficient, we may fill up the crannies between the spurs and the bell, and we have the formc.
Thusa, though the germ and type of capitals, is itself (except under some peculiar conditions) both ugly and insecure;bis the first type of capitals which carry light weight;c, of capitals which carry excessive weight.
§V.I fear, however, the reader may think he is going slightly too fast, and may not like having the capital forced upon him out of the cornice; but would prefer inventing a capital for the shaft itself, without reference to the cornice at all. We will do so then; though we shall come to the same result.
The shaft, it will be remembered, has to sustain the same weight as the long piece of wall which was concentrated into the shaft; it is enabled to do this both by its better form and better knit materials; and it can carry a greater weight than the space at the top of it is adapted to receive. The first point, therefore, is to expand this space as far as possible, and that in a form more convenient than the circle for the adjustment of the stones above. In general the square is a more convenientform than any other; but the hexagon or octagon is sometimes better fitted for masses of work which divide in six or eight directions. Then our first impulse would be to put a square or hexagonal stone on the top of the shaft, projecting as far beyond it as might be safely ventured; as ata,Fig. XX.This is the abacus. Our next idea would be to put a conical shaped stone beneath this abacus, to support its outer edge, as atb. This is the bell.
§VI.Now the entire treatment of the capital depends simply on the manner in which this bell-stone is prepared for fitting the shaft below and the abacus above. Placed as ata, inFig. XIX., it gives us the simplest of possible forms; with the spurs added, as atb, it gives the germ of the richest and most elaborate forms: but there are two modes of treatment more dexterous than the one, and less elaborate than the other, which are of the highest possible importance,—modes in which the bell is brought to its proper form by truncation.
§VII.Letdandf,Fig. XIX., be two bell-stones;dis part of a cone (a sugar-loaf upside down, with its point cut off);fpart of a four-sided pyramid. Then, assuming the abacus to be square,dwill already fit the shaft, but has to be chiselled to fit the abacus;fwill already fit the abacus, but has to be chiselled to fit the shaft.
From the broad end ofdchop or chisel off, in four vertical planes, as much as will leave its head an exact square. The vertical cuttings will form curves on the sides of the cone (curves of a curious kind, which the reader need not be troubled to examine), and we shall have the form ate, which is the root of the greater number of Norman capitals.
Fromfcut off the angles, beginning at the corners of the square and widening the truncation downwards, so as to give the form atg, where the base of the bell is an octagon, and itstop remains a square. A very slight rounding away of the angles of the octagon at the base ofgwill enable it to fit the circular shaft closely enough for all practical purposes, and this form, atg, is the root of nearly all Lombardic capitals.
If, instead of a square, the head of the bell were hexagonal or octagonal, the operation of cutting would be the same on each angle; but there would be produced, of course, six or eight curves on the sides ofe, and twelve or sixteen sides to the base ofg.
§VIII.The truncations ineandgmay of course be executed on concave or convex forms ofdandf; buteis usually worked on a straight-sided bell, and the truncation ofgoften becomes concave while the bell remains straight; for this simple reason,—that the sharp points at the angles ofg, being somewhat difficult to cut, and easily broken off, are usually avoided by beginning the truncation a little way down the side of the bell, and then recovering the lost ground by a deeper cut inwards, as here,Fig. XXI.This is the actual form of the capitals of the balustrades of St. Mark’s: it is the root of all the Byzantine Arab capitals, and of all the most beautiful capitals in the world, whose function is to express lightness.
§IX.We have hitherto proceeded entirely on the assumption that the form of cornice which was gathered together to produce the capital was the root of cornices,aofFig. V.But this, it will be remembered, was said in §VI.ofChap. VI.to be especially characteristic of southern work, and that in northern and wet climates it took the form of a dripstone.
Accordingly, in the northern climates, the dripstone gathered together forms a peculiar northern capital, commonly called the Early English,47owing to its especial use in that style.
There would have been no absurdity in this if shafts were always to be exposed to the weather; but in Gothic constructionsthe most important shafts are in the inside of the building. The dripstone sections of their capitals are therefore unnecessary and ridiculous.
§X.They are, however, much worse than unnecessary.
The edge of the dripstone, being undercut, has no bearing power, and the capital fails, therefore, in its own principal function; and besides this, the undercut contour admits of no distinctly visible decoration; it is, therefore, left utterly barren, and the capital looks as if it had been turned in a lathe. The Early English capital has, therefore, the three greatest faults that any design can have: (1) it fails in its own proper purpose, that of support; (2) it is adapted to a purpose to which it can never be put, that of keeping off rain; (3) it cannot be decorated.
The Early English capital is, therefore, a barbarism of triple grossness, and degrades the style in which it is found, otherwise very noble, to one of second-rate order.
§XI.Dismissing, therefore, the Early English capital, as deserving no place in our system, let us reassemble in one view the forms which have been legitimately developed, and which are to become hereafter subjects of decoration. To the formsa,b, andc,Fig. XIX., we must add the two simplest truncated formseandg,Fig. XIX., putting their abaci on them (as we considered their contours in the bells only), and we shall have the five forms now given in parallel perspective inFig. XXII., which are the roots of all good capitals existing, or capable of existence, and whose variations, infinite and a thousand times infinite, are all produced byintroduction of various curvatures into their contours, and the endless methods of decoration superinduced on such curvatures.
§XII.There is, however, a kind of variation, also infinite, which takes place in these radical forms, before they receive either curvature or decoration. This is the variety of proportion borne by the different lines of the capital to each other, and to the shafts. This is a structural question, at present to be considered as far as is possible.
§XIII.All the five capitals (which are indeed five orders with legitimate distinction; very different, however, from the five orders as commonly understood) may be represented by the same profile, a section through the sides ofa,b,d, ande, or through the angles ofc,Fig. XXII.This profile we will put on the top of a shaft, as at A,Fig. XXIII., which shaft we will suppose of equal diameter above and below for the sake of greater simplicity: in this simplest condition, however, relations of proportion exist between five quantities, any one or any two, or any three, or any four of which may change, irrespective of the others. These five quantities are:
1. The height of the shaft,a b;
2. Its diameter,b c;
3. The length of slope of bell,b d;
4. The inclination of this slope, or anglec b d;
5. The depth of abacus,d e.
For every change in any one of these quantities we have a new proportion of capital: five infinities, supposing change only in one quantity at a time: infinity of infinities in the sum of possible changes.
It is, therefore, only possible to note the general laws of change; every scale of pillar, and every weight laid upon it admitting, within certain limits, a variety out of which the architect has his choice; but yet fixing limits which the proportion becomes ugly when it approaches, and dangerous when it exceeds. But the inquiry into this subject is too difficult for the general reader, and I shall content myself with proving four laws, easily understood and generally applicable; for proof of which if the said reader care not, he may miss the next four paragraphs without harm.
§XIV.1.The more slender the shaft, the greater, proportionally, may be the projection of the abacus.For, looking back toFig. XXIII., let the heighta bbe fixed, the lengthd b, the angled b c, and the depthd e. Let the single quantityb cbe variable, let B be a capital and shaft which are found to be perfectly safe in proportion to the weight they bear, and let the weight be equally distributed over the whole of the abacus. Then this weight may be represented by any number of equal divisions, suppose four, asl,m,n,r, of brickwork above, of which each division is one fourth of the whole weight; and let this weight be placed in the most trying way on the abacus, that is to say, let the masseslandrbe detached frommandn, and bear with their full weight on the outside of the capital. We assume, in B, that the width of abacuse fis twice as great as that of the shaft,b c,and on these conditions we assume the capital to be safe.
Butb cis allowed to be variable. Let it becomeb2c2at C, which is a length representing about the diameter of a shaft containing half the substance of the shaft B, and, therefore, able to sustain not more than half the weight sustained by B.But the slopeb dand depthd eremaining unchanged, we have the capital of C, which we are to load with only half the weight ofl,m,n,r, i. e., withlandralone. Therefore the weight oflandr, now represented by the massesl2,r2, is distributed over the whole of the capital. But the weightrwas adequately supported by the projecting piece of the first capitalh f c: much more is it now adequately supported byi h,f2c2. Therefore, if the capital of B was safe, that of C is more than safe. Now in B the lengthe fwas only twiceb c; but in C,e2f2will be found more than twice that ofb2c2. Therefore, the more slender the shaft, the greater may be the proportional excess of the abacus over its diameter.
§XV.2.The smaller the scale of the building, the greater may be the excess of the abacus over the diameter of the shaft.This principle requires, I think, no very lengthy proof: the reader can understand at once that the cohesion and strength of stone which can sustain a small projecting mass, will not sustain a vast one overhanging in the same proportion. A bank even of loose earth, six feet high, will sometimes overhang its base a foot or two, as you may see any day in the gravelly banks of the lanes of Hampstead: but make the bank of gravel, equally loose, six hundred feet high, and see if you can get it to overhang a hundred or two! much more if there be weight above it increased in the same proportion. Hence, let any capital be given, whose projection is just safe, and no more, on its existing scale; increase its proportions every way equally, though ever so little, and it is unsafe; diminish them equally, and it becomes safe in the exact degree of the diminution.
Let, then, the quantitye d, and angled b c, at A ofFig. XXIII., be invariable, and let the lengthd bvary: then we shall have such a series of forms as may be represented bya, b, c,Fig. XXIV., of whichais a proportion for a colossal building,bfor a moderately sized building, whileccould only be admitted on a very small scale indeed.
§XVI. 3.The greater the excess of abacus, the steeper must be the slope of the bell, the shaft diameter being constant.
This will evidently follow from the considerations in the last paragraph; supposing only that, instead of the scale of shaft and capital varying together, the scale of the capital varies alone. For it will then still be true, that, if the projection of the capital be just safe on a given scale, as its excess over the shaft diameter increases, the projection will be unsafe, if the slope of the bell remain constant. But it may be rendered safe by making this slope steeper, and so increasing its supporting power.
Thus let the capitala,Fig. XXV., be just safe. Then the capitalb, in which the slope is the same but the excess greater, is unsafe. But the capitalc, in which, though the excess equals that ofb, the steepness of the supporting slope is increased, will be as safe asb, and probably as strong asa.48
§XVII. 4.The steeper the slope of the bell, the thinner may be the abacus.
The use of the abacus is eminently to equalise the pressure over the surface of the bell, so that the weight may not by any accident be directed exclusively upon its edges. In proportion to the strength of these edges, this function of the abacus is superseded, and these edges are strong in proportionto the steepness of the slope. Thus inFig. XXVI., the bell atawould carry weight safely enough without any abacus, but that atcwould not: it would probably have its edges broken off. The abacus superimposed might be onavery thin, little more than formal, as atb; but oncmust be thick, as atd.
§XVIII. These four rules are all that are necessary for general criticism; and observe that these are only semi-imperative,—rules of permission, not of compulsion. Thus Law 1 asserts that the slender shaftmayhave greater excess of capital than the thick shaft; but it need not, unless the architect chooses; his thick shaftsmusthave small excess, but his slender ones need not have large. So Law 2 says, that as the building is smaller, the excessmaybe greater; but it need not, for the excess which is safe in the large is still safer in the small. So Law 3 says that capitals of great excess must have steep slopes; but it does not say that capitals of small excess may not have steep slopes also, if we choose. And lastly, Law 4 asserts the necessity of the thick abacus for the shallow bell; but the steep bell may have a thick abacus also.
§XIX. It will be found, however, that in practice some confession of these laws will always be useful, and especially of the two first. The eye always requires, on a slender shaft, a more spreading capital than it does on a massy one, and a bolder mass of capital on a small scale than on a large. And, in the application of the first rule, it is to be noted that a shaft becomes slender either by diminution of diameter or increase of height; that either mode of change presupposes the weight above it diminished, and requires an expansion of abacus. I know no mode of spoiling a noble building more frequent in actual practice than the imposition of flat and slightly expanded capitals on tall shafts.
§XX. The reader must observe, also, that, in the demonstration of the four laws, I always assumed the weight above to begiven. By the alteration of this weight, therefore, the architect has it in his power to relieve, and therefore alter, the forms of his capitals. By its various distribution on their centres or edges, the slope of their bells and thickness of abaci will be affected also; so that he has countless expedients at his command for the various treatment of his design. He can divide his weights among more shafts; he can throw them in different places and different directions on the abaci; he can alter slope of bells or diameter of shafts; he can use spurred or plain bells, thin or thick abaci; and all these changes admitting of infinity in their degrees, and infinity a thousand times told in their relations: and all this without reference to decoration, merely with the five forms of block capital!
§XXI. In the harmony of these arrangements, in their fitness, unity, and accuracy, lies the true proportion of every building,—proportion utterly endless in its infinities of change, with unchanged beauty. And yet this connexion of the frame of their building into one harmony has, I believe, never been so much as dreamed of by architects. It has been instinctively done in some degree by many, empirically in some degree by many more; thoughtfully and thoroughly, I believe, by none.
§XXII. We have hitherto considered the abacus as necessarily a separate stone from the bell: evidently, however, the strength of the capital will be undiminished if both are cut out of one block. This is actually the case in many capitals, especially those on a small scale; and in others the detached upper stone is a mere representative of the abacus, and is much thinner than the form of the capital requires, while the true abacus is united with the bell, and concealed by its decoration, or made part of it.
§XXIII. Farther. We have hitherto considered bell and abacus as both derived from the concentration of the cornice. But it must at once occur to the reader, that the projection of the under stone and the thickness of the upper, which are quite enough for the work of the continuous cornice, may not be enough always, or rather are seldom likely to be so, for the harder work of the capital. Both may have to be deepenedand expanded: but as this would cause a want of harmony in the parts, when they occur on the same level, it is better in such case to let theentirecornice form the abacus of the capital, and put a deep capital bell beneath it.
§XXIV. The reader will understand both arrangements instantly by two examples.Fig. XXVII.represents two windows, more than usually beautiful examples of a very frequent Venetian form. Here the deep cornice or string course which runs along the wall of the house is quite strong enough for the work of the capitals of the slender shafts: its own upper stone is therefore also theirs; its own lower stone, by its revolution or concentration, forms their bells: but to mark the increased importance of its function in so doing, it receives decoration, as the bell of the capital, which it did not receive as the under stone of the cornice.
InFig. XXVIII., a little bit of the church of Santa Fosca at Torcello, the cornice or string course, which goes round every part of the church, is not strong enough to form the capitals of the shafts. It therefore forms their abaci only; and in order to mark the diminished importance of its function, it ceases to receive, as the abacus of the capital, the decoration which it received as the string course of the wall.
This last arrangement is of great frequency in Venice, occurring most characteristically in St. Mark’s: and in the Gothic of St. John and Paul we find the two arrangements beautifully united, though in great simplicity; the stringcourses of the walls form the capitals of the shafts of the traceries; and the abaci of the vaulting shafts of the apse.
§XXV. We have hitherto spoken of capitals of circular shafts only: those of square piers are more frequently formed by the cornice only; otherwise they are like those of circular piers, without the difficulty of reconciling the base of the bell with its head.
§XXVI. When two or more shafts are grouped together, their capitals are usually treated as separate, until they come into actual contact. If there be any awkwardness in the junction, it is concealed by the decoration, and one abacus serves, in most cases, for all. The double group,Fig. XXVII., is the simplest possible type of the arrangement. In the richer Northern Gothic groups of eighteen or twenty shafts cluster together, and sometimes the smaller shafts crouch under the capitals of the larger, and hide their heads in the crannies, with small nominal abaci of their own, while the larger shafts carry the serviceable abacus of the whole pier, as in the nave of Rouen. There is, however, evident sacrifice of sound principle in this system, the smaller abaci being of no use. They are the exact contrary of the rude early abacus at Milan, given inPlate XVII.There one poor abacus stretched itself out to do all the work: here there are idle abaci getting up into corners and doing none.
§XXVII. Finally, we have considered the capital hitherto entirely as an expansion of the bearing power of the shaft, supposing the shaft composed of a single stone. But, evidently, the capital has a function, if possible, yet more important, when the shaft is composed of small masonry. It enables all that masonry to act together, and to receive the pressure from above collectively and with a single strength. And thus, considered merely as a large stone set on the top of the shaft, it is a feature of the highest architectural importance, irrespective of its expansion, which indeed is, in some very noble capitals, exceedingly small. And thus every large stone set at any important point to reassemble the force of smaller masonry and prepare it for the sustaining of weight, is a capital or “head” stone (the true meaning of the word) whether it project or not. Thus at 6, inPlate IV., the stones which support the thrust of the brickwork are capitals, which have no projection at all; and the large stones in the window above are capitals projecting in one direction only.
§XXVIII. The reader is now master of all he need know respecting construction of capitals; and from what has been laid before him, must assuredly feel that there can never be any new system of architectural forms invented; but that all vertical support must be, to the end of time, best obtained by shafts and capitals. It has been so obtained by nearly every nation of builders, with more or less refinement in the management of the details; and the later Gothic builders of the North stand almost alone in their effort to dispense with the natural development of the shaft, and banish the capital from their compositions.
They were gradually led into this error through a series of steps which it is not here our business to trace. But they may be generalised in a few words.
§XXIX. All classical architecture, and the Romanesque which is legitimately descended from it, is composed of boldindependent shafts, plain or fluted, with bold detached capitals, forming arcades or colonnades where they are needed; and of walls whose apertures are surrounded by courses of parallel lines called mouldings, which are continuous round the apertures, and have neither shafts nor capitals. The shaft system and moulding system are entirely separate.
The Gothic architects confounded the two. They clustered the shafts till they looked like a group of mouldings. They shod and capitaled the mouldings till they looked like a group of shafts. So that a pier became merely the side of a door or window rolled up, and the side of the window a pier unrolled (vide last Chapter, §XXX.), both being composed of a series of small shafts, each with base and capital. The architect seemed to have whole mats of shafts at his disposal, like the rush mats which one puts under cream cheese. If he wanted a great pier he rolled up the mat; if he wanted the side of a door he spread out the mat: and now the reader has to add to the other distinctions between the Egyptian and the Gothic shaft, already noted in §XXVI. ofChap. VIII., this one more—the most important of all—that while the Egyptian rush cluster has only one massive capital altogether, the Gothic rush mat has a separate tiny capital to every several rush.
§XXX. The mats were gradually made of finer rushes, until it became troublesome to give each rush its capital. In fact, when the groups of shafts became excessively complicated, the expansion of their small abaci was of no use: it was dispensed with altogether, and the mouldings of pier and jamb ran up continuously into the arches.
This condition, though in many respects faulty and false, is yet the eminently characteristic state of Gothic: it is the definite formation of it as a distinct style, owing no farther aid to classical models; and its lightness and complexity render it, when well treated, and enriched with Flamboyant decoration, a very glorious means of picturesque effect. It is, in fact, this form of Gothic which commends itself most easily to the general mind, and which has suggested the innumerable foolish theories about the derivation of Gothic from tree trunks andavenues, which have from time to time been brought forward by persons ignorant of the history of architecture.
§XXXI. When the sense of picturesqueness, as well as that of justness and dignity, had been lost, the spring of the continuous mouldings was replaced by what Professor Willis calls the Discontinuous impost; which, being a barbarism of the basest and most painful kind, and being to architecture what the setting of a saw is to music, I shall not trouble the reader to examine. For it is not in my plan to note for him all the various conditions of error, but only to guide him to the appreciation of the right; and I only note even the true Continuous or Flamboyant Gothic because this is redeemed by its beautiful decoration, afterwards to be considered. For, as far as structure is concerned, the moment the capital vanishes from the shaft, that moment we are in error: all good Gothic has true capitals to the shafts of its jambs and traceries, and all Gothic is debased the instant the shaft vanishes. It matters not how slender, or how small, or how low, the shaft may be: wherever there is indication of concentrated vertical support, then the capital is a necessary termination. I know how much Gothic, otherwise beautiful, this sweeping principle condemns; but it condemns not altogether. We may still take delight in its lovely proportions, its rich decoration, or its elastic and reedy moulding; but be assured, wherever shafts, or any approximations to the forms of shafts, are employed, for whatever office, or on whatever scale, be it in jambs or piers, or balustrades, or traceries, without capitals, there is a defiance of the natural laws of construction; and that, wherever such examples are found in ancient buildings, they are either the experiments of barbarism, or the commencements of decline.
47Appendix 19, “Early English Capitals.”48In this case the weight borne is supposed to increase as the abacus widens; the illustration would have been clearer if I had assumed the breadth of abacus to be constant, and that of the shaft to vary.
47Appendix 19, “Early English Capitals.”
48In this case the weight borne is supposed to increase as the abacus widens; the illustration would have been clearer if I had assumed the breadth of abacus to be constant, and that of the shaft to vary.
§I.Wehave seen in the last section how our means of vertical support may, for the sake of economy both of space and material, be gathered into piers or shafts, and directed to the sustaining of particular points. The next question is how to connect these points or tops of shafts with each other, so as to be able to lay on them a continuous roof. This the reader, as before, is to favor me by finding out for himself, under these following conditions.
Lets,s,Fig. XXIX. opposite, be two shafts, with their capitals ready prepared for their work; anda,b,b, andc,c,c, be six stones of different sizes, one very long and large, and two smaller, and three smaller still, of which the reader is to choose which he likes best, in order to connect the tops of the shafts.
I suppose he will first try if he can lift the great stonea, and if he can, he will put it very simply on the tops of the two pillars, as at A.
Very well indeed: he has done already what a number of Greek architects have been thought very clever for having done. But suppose hecannotlift the great stonea, or suppose I will not give it to him, but only the two smaller stones atb,b; he will doubtless try to put them up, tilted against each other, as atd. Very awkward this; worse than card-house building. But if he cuts off the corners of the stones, so as to make each of them of the forme, they will stand up very securely, as at B.
But suppose he cannot lift even these less stones, but canraise those atc,c,c. Then, cutting each of them into the form ate, he will doubtless set them up as atf.
§II. This last arrangement looks a little dangerous. Is there not a chance of the stone in the middle pushing the others out, or tilting them up and aside, and slipping down itself between them? There is such a chance: and if by somewhat altering the form of the stones, we can diminish this chance, all the better. I must say “we” now, for perhaps I may have to help the reader a little.
The danger is, observe, that the midmost stone atfpushes out the side ones: then if we can give the side ones such a shape as that, left to themselves, they would fall heavily forward, they will resist this pushoutby their weight, exactly in proportion to their own particular inclination or desire to tumblein. Take one of them separately, standing up as atg; it is just possible it may stand up as it is, like the Tower of Pisa: but we want it to fall forward. Suppose we cut away the parts that are shaded athand leave it as ati, it is very certain it cannot stand alone now, but will fall forward to our entire satisfaction.
Farther: the midmost stone atfis likely to be troublesome chiefly by its weight, pushing down between the others; the more we lighten it the better: so we will cut it into exactly the same shape as the side ones, chiselling away the shaded parts, as ath. We shall then have all the three stonesk,l,m, of the same shape; and now putting them together, we have, at C, what the reader, I doubt not, will perceive at once to be a much more satisfactory arrangement than that atf.
§III. We have now got three arrangements; in one using only one piece of stone, in the second two, and in the third three. The first arrangement has no particular name, except the “horizontal:” but the single stone (or beam, it may be,) is called a lintel; the second arrangement is called a “Gable;” the third an “Arch.”
We might have used pieces of wood instead of stone in all these arrangements, with no difference in plan, so long as the beams were kept loose, like the stones; but as beams can be securely nailed together at the ends, we need not trouble ourselves so much about their shape or balance, and therefore the plan atfis a peculiarly wooden construction (the reader will doubtless recognise in it the profile of many a farm-house roof): and again, because beams are tough, and light, and long, as compared with stones, they are admirably adapted for the constructions at A and B, the plain lintel and gable, while that at C is, for the most part, left to brick and stone.
§IV. But farther. The constructions, A, B, and C, thoughvery conveniently to be first considered as composed of one, two, and three pieces, are by no means necessarily so. When we have once cut the stones of the arch into a shape like that ofk,l, andm, they will hold together, whatever their number, place, or size, as atn; and the great value of the arch is, that it permits small stones to be used with safety instead of large ones, which are not always to be had. Stones cut into the shape ofk,l, andm, whether they be short or long (I have drawn them all sizes atnon purpose), are called Voussoirs; this is a hard, ugly French name; but the reader will perhaps be kind enough to recollect it; it will save us both some trouble: and to make amends for this infliction, I will relieve him of the termkeystone. One voussoir is as much a keystone as another; only people usually call the stone which is last put in the keystone; and that one happens generally to be at the top or middle of the arch.
§V. Not only the arch, but even the lintel, may be built of many stones or bricks. The reader may see lintels built in this way over most of the windows of our brick London houses, and so also the gable: there are, therefore, two distinct questions respecting each arrangement;—First, what is the line or direction of it, which gives it its strength? and, secondly, what is the manner of masonry of it, which gives it its consistence? The first of these I shall consider in this Chapter under the head of the Arch Line, using the term arch as including all manner of construction (though we shall have no trouble except about curves); and in the next Chapter I shall consider the second, under the head, Arch Masonry.
§VI. Now the arch line is the ghost or skeleton of the arch; or rather it is the spinal marrow of the arch, and the voussoirs are the vertebræ, which keep it safe and sound, and clothe it. This arch line the architect has first to conceive and shape in his mind, as opposed to, or having to bear, certain forces which will try to distort it this way and that; and against which he is first to direct and bend the line itself into as strong resistance as he may, and then, with his voussoirs and what else he can, to guard it, and help it, and keep it to its duty and inits shape. So the arch line is the moral character of the arch, and the adverse forces are its temptations; and the voussoirs, and what else we may help it with, are its armor and its motives to good conduct.
§VII. This moral character of the arch is called by architects its “Line of Resistance.” There is a great deal of nicety in calculating it with precision, just as there is sometimes in finding out very precisely what is a man’s true line of moral conduct; but this, in arch morality and in man morality, is a very simple and easily to be understood principle,—that if either arch or man expose themselves to their special temptations or adverse forces,outsideof the voussoirs or proper and appointed armor, both will fall. An arch whose line of resistance is in the middle of its voussoirs is perfectly safe: in proportion as the said line runs near the edge of its voussoirs, the arch is in danger, as the man is who nears temptation; and the moment the line of resistance emerges out of the voussoirs the arch falls.
§VIII. There are, therefore, properly speaking, two arch lines. One is the visible direction or curve of the arch, which may generally be considered as the under edge of its voussoirs, and which has often no more to do with the real stability of the arch, than a man’s apparent conduct has with his heart. The other line, which is the line of resistance, or line of good behavior, may or may not be consistent with the outward and apparent curves of the arch; but if not, then the security of the arch depends simply upon this, whether the voussoirs which assume or pretend to the one line are wide enough to include the other.
§IX. Now when the reader is told that the line of resistance varies with every change either in place or quantity of the weight above the arch, he will see at once that we have no chance of arranging arches by their moral characters: we can only take the apparent arch line, or visible direction, as a ground of arrangement. We shall consider the possible or probable forms or contours of arches in the present Chapter, and in the succeeding one the forms of voussoir and other helpwhich may best fortify these visible lines against every temptation to lose their consistency.
§X. Look back toFig. XXIX.Evidently the abstract or ghost line of the arrangement at A is a plain horizontal line, as here ata,Fig. XXX.The abstract line of the arrangement at B,Fig. XXIX., is composed of two straight lines, set against each other, as here atb. The abstract line of C,Fig. XXIX., is a curve of some kind, not at present determined, supposec,Fig. XXX.Then, asbis two of the straight lines ata, set up against each other, we may conceive an arrangement,d, made up of two of the curved lines atc, set against each other. This is called a pointed arch, which is a contradiction in terms: it ought to be called a curved gable; but it must keep the name it has got.
Nowa,b,c,d,Fig. XXX., are the ghosts of the lintel, the gable, the arch, and the pointed arch. With the poor lintel ghost we need trouble ourselves no farther; there are no changes in him: but there is much variety in the other three, and the method of their variety will be best discerned by studyingbandd, as subordinate to and connected with the simple arch atc.
§XI. Many architects, especially the worst, have been very curious in designing out of the way arches,—elliptical arches, and four-centred arches, so called, and other singularities. The good architects have generally been content, and we for the present will be so, with God’s arch, the arch of the rainbow and of the apparent heaven, and which the sun shapes for us as it sets and rises. Let us watch the sun for a moment as it climbs: when it is a quarter up, it will give us the archa,Fig. XXXI.; when it is half up,b, and when three quartersup,c. There will be an infinite number of arches between these, but we will take these as sufficient representatives of all. Thenais the low arch,bthe central or pure arch,cthe high arch, and the rays of the sun would have drawn for us their voussoirs.
§XII. We will take these several arches successively, and fixing the top of each accurately, draw two right lines thence to its base,d,e,f,Fig. XXXI.Then these lines give us the relative gables of each of the arches;dis the Italian or southern gable,ethe central gable,fthe Gothic gable.
§XIII. We will again take the three arches with their gables in succession, and on each of the sides of the gable, between it and the arch, we will describe another arch, as atg,h,i. Then the curves so described give the pointed arches belonging to each of the round arches;g, the flat pointed arch,h, the central pointed arch, andi, the lancet pointed arch.
§XIV. If the radius with which these intermediate curves are drawn be the base off, the last is the equilateral pointedarch, one of great importance in Gothic work. But between the gable and circle, in all the three figures, there are an infinite number of pointed arches, describable with different radii; and the three round arches, be it remembered, are themselves representatives of an infinite number, passing from the flattest conceivable curve, through the semicircle and horseshoe, up to the full circle.
The central and the last group are the most important. The central round, or semicircle, is the Roman, the Byzantine, and Norman arch; and its relative pointed includes one wide branch of Gothic. The horseshoe round is the Arabic and Moorish arch, and its relative pointed includes the whole range of Arabic and lancet, or Early English and French Gothics. I mean of course by the relative pointed, the entire group of which the equilateral arch is the representative. Between it and the outer horseshoe, as this latter rises higher, the reader will find, on experiment, the great families of what may be called the horseshoe pointed,—curves of the highest importance, but which are all included, with English lancet, under the term, relative pointed of the horseshoe arch.
§XV. The groups above described are all formed of circular arcs, and include all truly useful and beautiful arches for ordinary work. I believe that singular and complicated curves are made use of in modern engineering, but with these the general reader can have no concern: the Ponte della Trinita at Florence is the most graceful instance I know of such structure; the arch made use of being very subtle, and approximating to the low ellipse; for which, in common work, a barbarous pointed arch, called four-centred, and composed of bits of circles, is substituted by the English builders. The high ellipse, I believe, exists in eastern architecture. I have never myself met with it on a large scale; but it occurs in the niches of the later portions of the Ducal palace at Venice, together with a singular hyperbolic arch,ainFig. XXXIII., to be described hereafter: with such caprices we are not here concerned.
§XVI. We are, however, concerned to notice the absurdityof another form of arch, which, with the four-centred, belongs to the English perpendicular Gothic.
Taking the gable of any of the groups inFig. XXXI.(suppose the equilateral), here atb, inFig. XXXIII., the dotted line representing the relative pointed arch, we may evidently conceive an arch formed by reversed curves on the inside of the gable, as here shown by the inner curved lines. I imagine the reader by this time knows enough of the nature of arches to understand that, whatever strength or stability was gained by the curve on theoutsideof the gable, exactly so much is lost by curves on theinside. The natural tendency of such an arch to dissolution by its own mere weight renders it a feature of detestable ugliness, wherever it occurs on a large scale. It is eminently characteristic of Tudor work, and it is the profile of the Chinese roof (I say on a large scale, because this as well as all other capricious arches, may be made secure by their masonry when small, but not otherwise). Some allowable modifications of it will be noticed in the chapter on Roofs.
§XVII. There is only one more form of arch which we have to notice. When the last described arch is used, not as the principal arrangement, but as a mere heading to a common pointed arch, we have the formc,Fig. XXXIII.Now this is better than the entirely reversed arch for two reasons; first, less of the line is weakened by reversing; secondly, the double curve has a very high æsthetic value, not existing in the mere segments of circles. For these reasons arches of this kind are not only admissible, but even of great desirableness, when their scale and masonry render them secure, but above a certain scale they are altogether barbarous; and, with the reversedTudor arch, wantonly employed, are the characteristics of the worst and meanest schools of architecture, past or present.
This double curve is called the Ogee; it is the profile of many German leaden roofs, of many Turkish domes (there more excusable, because associated and in sympathy with exquisitely managed arches of the same line in the walls below), of Tudor turrets, as in Henry the Seventh’s Chapel, and it is at the bottom or top of sundry other blunders all over the world.
§XVIII. The varieties of the ogee curve are infinite, as the reversed portion of it may be engrafted on every other form of arch, horseshoe, round, or pointed. Whatever is generally worthy of note in these varieties, and in other arches of caprice, we shall best discover by examining their masonry; for it is by their good masonry only that they are rendered either stable or beautiful. To this question, then, let us address ourselves.
§I.Onthe subject of the stability of arches, volumes have been written and volumes more are required. The reader will not, therefore, expect from me any very complete explanation of its conditions within the limits of a single chapter. But that which is necessary for him to know is very simple and very easy; and yet, I believe, some part of it is very little known, or noticed.
We must first have a clear idea of what is meant by an arch. It is a curvedshellof firm materials, on whose back a burden is to be laid ofloosematerials. So far as the materials above it arenot loose, but themselves hold together, the opening below is not an arch, but anexcavation. Note this difference very carefully. If the King of Sardinia tunnels through the Mont Cenis, as he proposes, he will not require to build a brick arch under his tunnel to carry the weight of the Mont Cenis: that would need scientific masonry indeed. The Mont Cenis will carry itself, by its own cohesion, and a succession of invisible granite arches, rather larger than the tunnel. But when Mr. Brunel tunnelled the Thames bottom, he needed to build a brick arch to carry the six or seven feet of mud and the weight of water above. That is a type of all arches proper.
§II. Now arches, in practice, partake of the nature of the two. So far as their masonry above is Mont-Cenisian, that is to say, colossal in comparison of them, and granitic, so that the arch is a mere hole in the rock substance of it, the form of the arch is of no consequence whatever: it may be rounded,or lozenged, or ogee’d, or anything else; and in the noblest architecture there is alwayssomecharacter of this kind given to the masonry. It is independent enough not to care about the holes cut in it, and does not subside into them like sand. But the theory of arches does not presume on any such condition of things; it allows itself only the shell of the arch proper; the vertebræ, carrying their marrow of resistance; and, above this shell, it assumes the wall to be in a state of flux, bearing down on the arch, like water or sand, with its whole weight. And farther, the problem which is to be solved by the arch builder is not merely to carry this weight, but to carry it with the least thickness of shell. It is easy to carry it by continually thickening your voussoirs: if you have six feet depth of sand or gravel to carry, and you choose to employ granite voussoirs six feet thick, no question but your arch is safe enough. But it is perhaps somewhat too costly: the thing to be done is to carry the sand or gravel with brick voussoirs, six inches thick, or, at any rate, with the least thickness of voussoir which will be safe; and to do this requires peculiar arrangement of the lines of the arch. There are many arrangements, useful all in their way, but we have only to do, in the best architecture, with the simplest and most easily understood. We have first to note those which regard the actual shell of the arch, and then we shall give a few examples of the superseding of such expedients by Mont-Cenisian masonry.
§III. What we have to say will apply to all arches, but the central pointed arch is the best for general illustration. Leta,Plate III., be the shell of a pointed arch with loose loading above; and suppose you find that shell not quite thick enough; and that the weight bears too heavily on the top of the arch, and is likely to break it in: you proceed to thicken your shell, but need you thicken it all equally? Not so; you would only waste your good voussoirs. If you have any common sense you will thicken it at the top, where a Mylodon’s skull is thickened for the same purpose (and some human skulls, I fancy), as atb. The pebbles and gravel above will now shootoff it right and left, as the bullets do off a cuirassier’s breastplate, and will have no chance of beating it in.
If still it be not strong enough, a farther addition may be made, as atc, now thickening the voussoirs a little at the base also. But as this may perhaps throw the arch inconveniently high, or occasion a waste of voussoirs at the top, we may employ another expedient.
§IV. I imagine the reader’s common sense, if not his previous knowledge, will enable him to understand that if the arch ata,Plate III., burstinat the top, it must burstoutat the sides. Set up two pieces of pasteboard, edge to edge, and press them down with your hand, and you will see them bend out at the sides. Therefore, if you can keep the arch from starting out at the pointsp,p, itcannotcurve in at the top, put what weight on it you will, unless by sheer crushing of the stones to fragments.
§V. Now you may keep the arch from starting out atpby loading it atp, putting more weight upon it and against it at that point; and this, in practice, is the way it is usually done. But we assume at present that the weight above is sand or water, quite unmanageable, not to be directed to the points we choose; and in practice, it may sometimes happen that we cannot put weight upon the arch atp. We may perhaps want an opening above it, or it may be at the side of the building, and many other circumstances may occur to hinder us.
§VI. But if we are not sure that we can put weight above it, we are perfectly sure that we can hang weight under it. You may always thicken your shell inside, and put the weight upon it as atx x, ind,Plate III.Not much chance of its bursting out atp, now, is there?
§VII. Whenever, therefore, an arch has to bear vertical pressure, it will bear it better when its shell is shaped as atbord, than as ata: banddare, therefore, the types of arches built to resist vertical pressure, all over the world, and from the beginning of architecture to its end. None others can be compared with them: all are imperfect except these.
The added projections atx x, ind, are calledCusps, and they are the very soul and life of the best northern Gothic; yet never thoroughly understood nor found in perfection, except in Italy, the northern builders working often, even in the best times, with the vulgar form ata.
The form atbis rarely found in the north: its perfection is in the Lombardic Gothic; and branches of it, good and bad according to their use, occur in Saracenic work.
§VIII. The true and perfect cusp is single only. But it was probably invented (by the Arabs?) not as a constructive, but a decorative feature, in pure fantasy; and in early northern work it is only the application to the arch of the foliation, so called, of penetrated spaces in stone surfaces, already enough explained in the “Seven Lamps,” Chap. III., p. 85et seq.It is degraded in dignity, and loses its usefulness, exactly in proportion to its multiplication on the arch. In later architecture, especially English Tudor, it is sunk into dotage, and becomes a simple excrescence, a bit of stone pinched up out of the arch, as a cook pinches the paste at the edge of a pie.
§IX. The depth and place of the cusp, that is to say, its exact application to the shoulder of the curve of the arch, varies with the direction of the weight to be sustained. I have spent more than a month, and that in hard work too, in merely trying to get the forms of cusps into perfect order: whereby the reader may guess that I have not space to go into the subject now; but I shall hereafter give a few of the leading and most perfect examples, with their measures and masonry.
§X. The reader now understands all that he need about the shell of the arch, considered as an united piece of stone.
He has next to consider the shape of the voussoirs. This, as much as is required, he will be able best to comprehend by a few examples; by which I shall be able also to illustrate, or rather which will force me to illustrate, some of the methods of Mont-Cenisian masonry, which were to be the second part of our subject.
§XI. 1 and 2,Plate IV., are two cornices; 1 from St. Antonio, Padua; 2, from the Cathedral of Sens. I want themfor cornices; but I have put them in this plate because, though their arches are filled up behind, and are in fact mere blocks of stone with arches cut into their faces, they illustrate the constant masonry of small arches, both in Italian and Northern Romanesque, but especially Italian, each arch being cut out of its own proper block of stone: this is Mont-Cenisian enough, on a small scale.