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King's Colleye Chapel, Cambridge, has no side aisles, but in lieu of them are small chapels between the buttresses, which are not interrupted in their depth, their whole strength being requisite to maintain in equilibrio the highly wrought stone vault; this they have hitherto perfectly done, to the admiration of all who have studied its principles of construction. The chapel' is divided in its length into twelve equal divisions or severies, each of which is formed of four quadrants of a concave parabolic conoid standing on their apex, and is bounded by a main ribor arch of masonry which has its abutments secured by the weighty huttresses added to the outer walls. The width of each severy from centre to centre is 24 feet, the thickness of the buttresses being 3 feet 7 inches, and the length of the chapel between them 20 feet 6 inches; their depth is 13 feet 6 inches in the clear.
The transverse section shows more particularly the proportion of mass and void, which are here equal : the total extent or width from the face of one but. tress to that of the other is 84 feet, and the clear width 42 feet; the height from the pavement to the top of the stone vault is 80 feet 1 inch, though this varies from the pavement being out of the level; the thickness of the walls at top is 5 feet 7} inches; in it is a gallery 2 feet 14 inch wide, and 7 feet high, communicating entirely around the building.
The height of the cluster column, whose capital receives the points of the inverted cones, is 59 feet 3 inches, so that the arch, which is struck from four centres, does not rise more than 18 feet 6 inches, and the intersections take place at one quarter of the span when the height is 15 feet 6 inches: this arch or stone rib is 2 feet in depth and 18 inches in breadth, formed of twelve voussoirs on each side, the joints radiating to the centres respectively; it abuts at its extremities against the ponderous buttresses, and remains steadfast and immovable, dividing, as before stated, the vault into several severies.
The plan of the main piers shows that there has been no after-thought grafted upon the original design, which, in all probability, was commenced soon after the year 1446, as we find that a stone quarry at Haselwode, and another at Huddlestone, in Yorkshire, were granted, for the works to be carried on here. The stone roof does not appear to have been commenced till about 1512, the indenture concerning it bearing date the fourth Fig. 1307. KING'S COLLEGE CHAPEL. year of King Henry VIII. ; in this document Thomas Larke is called the “surveyor," John Wastell the “master mason,” and Henry Semerk one of the “wardens," the two latter agreeing to set up a sufficient vawte, according to a plat signed ; the stone to be from the Weldon quarries : the contracting parties were also to provide“ lyme, scaffoldyng, cinctores, moles, ordinaunces,” and “ every other thyng required for the same vawting : the timbers
of two severies of the “great scaffolding" were given them for the removal of the whole ; and they were to have the uses of all “ gynnes, whels, cables, hobynatts, saws, &c. ;” they were to pay for the stone, and to bave 1001. for each severy, or 12001. for the whole, money being advanced for wages as the works proceeded : the " chare roff,” as the vault is called was to be sufficiently buttressed, and the whole performed in a perfect manner.
The extreme width, measured from the face of one buttress to that of the other, is 84 feet, and from north to south, from the centre of one pier to that of the other, 24 feet; thus the area comprised in a severy, or space between two lines drawn through the centres of the buttresses on the plan, is 2016 feet, exactly double the area of one of the severies of St. George's Chapel, Windsor : the extreme width is the same, but the difference arises from the divisions in the one being double that of the other, as ineasured from east to
The area of the nave, 42 x 24
of the chapel on one side
ditto on the other of the walls on one side
ditto on the other Hence we have for the areas of the space or void on the plan 1680 feet, and for the walls and pier 336 feet, or one-sixth of the whole 2016 feet, similar proportions to those which we
Feet. 1008 336 336 168 168
shall afterwards find in St. George's Chapel, Windsor. In King's College the nave comprises half the entire area of a severy, and the remaining half is divided into three, one of which is given to each of the chapels, and the other divided between the points of support: in this beautiful building, with its majestically con. trived roof of stone, the lightest construction is adopted. The catenarian curve exhibits the direction of the thrust of the vault, which falls within the base.
The stone roof we are now examining differs somewhat from that of Henry VII.'s chapel at Westminster; the area of the points of support is only one-half of those in the latter elegant example; in no instance have we so much effect produced by the mason's art, with so small a quantity of material: it is evident that the gradual changes made in the architecture of the mediæval period led at last to the greatest perfection, beyond which it seems impossible for us to advance.
In selecting a style of any one period, it may be fairly asked whether the principles found in the latter, or the economy adopted in the con. structions of the 15th century, might not be applied to it, and the same effect produced,- the section of the chapter-house at Wells, for instance, lightened of half its material : undoubtedly it might, for the lofty pointed arch, not having the thrust which the latter, struck from four centres, had, would exert less thrust, and be in favour of such a change.
But at the present day, when copies are rigidly made of the finest examples of each style, it would seem a bold innovation to suggest such an adoption; still it might be introduced, and probably would have been, had the freemasons continued an operative fraternity, and been required to build in the Lancet or other style, which superseded it. The same decora
Fig. 1309. VAULTING OP KING'S COLLEGE CHAPEL. tions an ) form of arch may be used in the later styles as in the earlier, as far as construction is concerned, and we have evidence of sufficient strength in the example before us; the principles are the same in each, though they may differ in form ; there would be no more difficulty in transforming one style to that of another, than was experienced by William of Wykeham, when he changed the Saxon nave of Winchester to the Perpendicular.
On the section shown at fig. 1308. a line is drawn exhibiting the catenarian curve, for the purpose of showing that the abutment piers are set out in correspondence with its principles; it is not contended that a knowledge of this curve guided the freemasons in proportioning their piers, or that their flying buttresses were always placed within it; but it is singular that in those structures where their true position seems to have been decided, the catenarian passes through them.
Bath Abbey section (fig. 1319.) is an example which exhibits this most perfectly; and by a comparison of its section with that at Wells (fig. 1272.), it will be perceived that the struts are differently placed, and that the earlier example is defective : fig. 1298, represents Roslyn
Chapel, in which there is evidently some improvement; but at the time of its construction perfect knowledge on this subject had not been attained. In a catenarian chain formed of links of equal length, every side is a tangent to the curve, and the direction of each link is at right angles to it, acting in a direction perpendicular to the line it forms in the catenaria ; and hence its useful application to the science of construction. It is quite clear that wherever the curve passes through the section of a building, stability is obtained ; and where it does not, it is doubtful : certainly the best application of Aying buttresses is that which can be tested by this principle.
The main arches of the roof abut against the outer buttresses, and spring from a cluster of mouldings set round a circular pier; the situation of the small columns and hollows which decorate it being determined by the crossing of equilateral triangles. The ribs of each severy abut in the centre upon a circle 3 feet 6 inches in diameter, formed of two stones, and indicated by No. 1.: in the middle is a mortise-hole 9 inches square; No. 2. is in width 17 inches in the widest part; No. 3. is 2 feet 2 inches; No. 4., 3 feet 8 inches; No. 5., the same; No. 6., 3 feet 3 inches; No. 7. 4 feet 3 inches; No. 8., the same; No. 9., 3 feet 2 inches, and No. 10., which abuts against the outer wall, 4 feet.
By a reference to the plan on fig. 1312., it will be understood how the several rings of voussoirs which compose the quarter of the para. bolic conoid abut and are locked one into the other : the construction of this vault is somewhat similar to that adopted by Soufflout at the Church of St. Geneviève at Paris, although his manner of applying it materially
Fig. 1511, differs.
The buttress in the present Fig. 1310. KING'S COLLEGE CHAPEL: RIBS OY VAULT. example has an area of 56 feet, equal to that of the piers, to which it is attached; or the two piers and buttresses together have an area of 224 feet : it is curious to find that of the 336 feet before given to the points of support, one-sixth should be applied to the piers, one-sixth to the buttresses, and the other portion to the walls between; for 55 ft. 6 in. x 6=336 feet — the area of the points of support taken on both sides ; so equally are the parts even distributed.
When the Normans first used flying buttresses, as at the Cathedral at Chartres, the Abbaye aux Hommes at Caen, and several other buildings, they abutted them against the ordinary outside wall; but it was soon discovered that a greater resistance was necessary to oppose the thrust, and prevent the abutments from yielding. Salisbury Cathedral was probably one of the earliest where flying buttresses were used ; and the opinion of Sir Christopher Wren is worthy of quoting upon this subject, as it applies more particularly to the first constructed, and not so immediately to those erected in the fourteenth or fifteenth centuries. “ Almost all the cathedrals of the Gothic form are weak and defective in the poise of the vault of the aisles; as for the vaults of the nave, they are on both sides equally supported and propped up from spreading by the bowes or flying buttresses, which rise from the outward walls of the aisles: but for the vaults of the aisles, they are indeed supported on the outside by the buttresses ; but inwardly, they have no other stay but the pillars themselves, which, as they are usually proportioned, if they stood alone, without the weight above, could not resist the spreading of the aisles one minute : true, indeed, the great load above of the walls and vaulting of the nave should seem to confine the pillars
in their perpendicular station, that there should be no need of butment inwards, but esperience hath shown the contrary, and there is scarce any Gothic cathedral, that I have
KING'S COLLEGE CHAPEL : PIERS. seen at home or abroad, wherein I have not observed the pillars to yield and bend inwards from the weight of the vault of the aisle ; but this defect is the most conspicuous upon the angular pillars of the cross, for there not only the vault wants butment, but also the
KING'S COLLEGE OHAPEL: BUTTRESSES, ETC. angular arches that rest upon that pillar, and therefore both conspire to thrust it inwards towards the centre of the cross."
At King's College chapel, flying buttresses are dispensed with, and happily the knowledge of construction had arrived at such perfection, when its astonishing vault was projected, that we have no evidence whatever of its yielding in any part.
It may seem extraordinary that the Pointed style made so little progress in Italy, the Byzantine being always preferred: the architects of that country were probably unwilling to relinquish a mode of construction so economical, half only of the material employed in the lightest, and a quarter in the earliest of the Gothic style, being required for the basilica : for example, where 100 rods of stonework would be used in the latter, 200 would be necessary for the style practised at King's College, St. George's Chapel, and Bath Abbey Church, and 400 for that of the Chapter-house at Wells; this result would lead to the conclusion, that no style is so well adapted for the wants of the present day as the Byzantine.