[Illustration: St. Faith’s Chapel, Westminster Abbey. View looking
west.]
placed side by side, one apparently the square, and the other of the
narrowest proportions; and in the outer vestibule beautiful miniature
vaulting, on minute columns, and with the segmental arch; while in St.
Faith’s Chapel, hard by, we have an excellent example of the sexpartite
vault (Figs. 379, 380). Parts of the aisles, too, are remarkable for the
subdivision of their bays by transverse arches of the double orders of
mouldings, giving a great nobleness and strength to their effect; and
all these varieties are carried out with admirable detail and studied
art.
It would lead me into too great length if I were to go into the moulding
of the ribs, their combinations where grouping and intersecting one
another in the springers, and the mode in which the shafts are arranged
for their support. My illustrations will, however, do much to explain
this. I must not omit to mention that in French buildings, and
frequently in the earlier English specimens, the plans of the abaci of
these shafts assume both forms and positions indicating the general
section and the directions of the ribs they carry,[59] and that this is
even shared by the _bases_; showing that the vaulting was the _very
first_ thing thought of and designed; and that, from the very floor of
the building, it influenced the general design. This was lost in England
by the introduction of the circular abacus.
I have hitherto dwelt wholly upon vaulting which has none but what I
have termed _functional_ ribs; that is to say, such as have a specific
utility, as transverse ribs to mark the boundaries of the bays, and to
strengthen the vault in its main span; diagonal ribs to fortify the
angles of intersection; and wall-ribs to support the vaulting surfaces
at their junction with the walls; and occasionally ridge ribs, though
these more properly belong to the succeeding stage. The next stage in
the history of vaulting is that in which other than merely functional
ribs are made use of--intermediate ribs, in fact, to subdivide the
spaces between those used during the previous period.
[Illustration: Fig. 381.]
[Illustration: Fig. 382.]
In square vaulting, _one_ such additional rib is more usually introduced
in each space (Fig. 381). In very oblong vaults _two_, and even _three_,
were often introduced in the side spaces, though only one in the middle
spaces (Fig. 382). It is clear that this addition necessitates the use
of ridge ribs, as, without them, the point at which the intermediate
ribs meet at their apex would want abutment. So reasonable, indeed, was
this motive, that we often find the ridge rib to have been omitted
between the intermediate ribs and the wall ribs, because there its use
ceases.
One thing which followed the use of these additional ribs was the
curious serrated plan of the filling in. The oblique position of these
ribs would, if the plan of the filling in remained unaltered, cause the
fillet or reveal of the rib nearly to vanish on one side, and to become
very wide on the other. This led them to change the plan.
On looking at the top surface of vaulting where the ribs are visible, it
is at once seen that this was also necessitated by a structural cause,
as without it the filling in would not rest well upon the ribs (Fig.
383).
[Illustration: Fig. 383.]
[Illustration: Fig. 384.--Westminster Abbey. Vaulting west of the
crossing.]
No better specimen of this form of vaulting can be referred to than that
of the presbytery at Ely, built about 1240 to 1250, and the four bays
immediately to the west of the crossing in Westminster Abbey, erected by
Edward I. about 1280 to 1300 (Fig. 384). The latter is the more perfect,
as having level ridges; the former, curiously enough, having ridges to
the side cells which rise from the intersection towards the walls. I may
mention that it is very common for vaulting with intermediate ribs to
have ridges rising rapidly towards the central boss.
The use of these additional ribs became, from the latter part of the
thirteenth century, rather the rule than the exception.
I may mention early specimens of it at Chester, both in the
Chapter-house (Fig. 385) and in the Lady Chapel, the latter with raised
ridges; but in each the addition being only in the side cells. The
Chapter-house at Wells has the intermediate ribs added throughout to
those of the more normal examples at Westminster and Salisbury, giving
its vaulting a peculiarly full and rich, though rather crowded, effect.
Bosses are usually introduced at all points of meeting, adding greatly
to the richness of the whole.
[Illustration: Fig. 385.--Chapter-house, Chester Cathedral.]
Though I have called these ribs _non-functional_, such is the case only
in a limited sense, for, though not necessary, they nevertheless do
their work: they divide and strengthen the vaulting spaces, and tend to
do away with the necessity (if such may be supposed to exist) for any
great thickness of filling in. They form, in fact, a stone framework or
centering, with frequent supports on which the vaulting permanently
rests. Nearly the whole of Exeter Cathedral is groined in this manner,
and excellent specimens, though of rather late date, may be seen in the
west and south walks of the cloisters of Westminster Abbey, and in the
two vestibules through which the cloister is approached. These have the
advantage of close proximity to the eye, which enables one to study them
with facility.
The next step in the history of vaulting may be said to be wholly
decorative in its motive. It is the addition of short cross ribs between
those already described, and arranged in patterns, such as stars, etc.,
round the central bosses, adding much to the complexity and ornamental
character of the vault, and making a farther increase to the number of
the bosses.
Wonderful skill is often evinced in the arrangement of these patterns,
which, traversing the changing planes or surfaces of the vaulting,
produce in the perspective an extraordinary diversity of effect. These
ribs have received from Professor Willis the name of “Liernes,” a term
given by Philibert de l’Orme to the ridge-ribs (perhaps in common with
these), but, as we are short of an English name for these cross-ribs, it
comes in conveniently to our aid. The term means, I believe, in
carpentry, a short joist or rail, serving as a tie to steady other
timbers, which is very appropriate to its use (real or apparent) in
vaulting.
We have a few excellent specimens of this class of vaulting in London;
more particularly that of St. Stephen’s crypt, and of a bay of the
cloisters opposite the entrance to the Chapter-house, both erected in
the first half of the fourteenth century.
In the former, both the intermediate ribs and the liernes are very
subservient in size to the main ribs; which gives an excellent effect:
indeed, I know of no work more studious in design and detail than that
piece of vaulting.
The vaulting of three bays of the eastern limb of Ely Cathedral, built
by Alan de Walsingham at about the same period, is also of excellent
design, as is that of the chancel of Nantwich Church in Cheshire.
I am imitating the last-named to a certain extent in timber in the
vaulting of the nave of Chester Cathedral, where, though the springers
exist, the vaulting has never been completed.
Liernes are not placed at right angles to the surface of the vaulting,
but in a vertical plane; perhaps from the facility it affords for
setting them out on the ground plan.
We find the same cause regulating the geometrical system adopted for
setting out the stones forming the bosses, which had also to contain a
short piece of the impinging ribs. Professor Willis, in his admirable
papers on vaulting, gives in minute detail the method adopted, showing
that, to facilitate the operation, they made the upper surface of the
boss-stone _horizontal_, to serve as a sort of drawing-board on which to
draw the plan of the intersecting ribs. I have tested this in several
instances. In the western part of the nave at Westminster, there being
no outer thickness of stone vaulting, the boss-stones appear, and their
surfaces are horizontal. On sweeping away the accumulation of dust and
rubbish which covers them, I found, sure enough, the centre and side
lines of all the ribs carefully drawn upon them.
In the lierne vaulting at Ely, though there has been an outer thickness
of stonework, it was cleared away in the last century for the sake of
lightness, so that the boss-stones, once concealed, are now visible. On
clearing them from obstructions, I again found, as at Westminster, the
lines of the ribs (here much more complex), carefully set out upon the
top of the stones. Each of these little stone tables, in fact, has drawn
out upon it the bit of the full-size plan of the vaulting which its
surface would contain.
The lierne vaulting, though commencing as early as the first quarter of
the fourteenth century, was so popular as to be continued throughout the
remaining periods of Gothic architecture, used side by side, and often
in union with other and later systems. The same was naturally the case
with ordinary rib vaulting, so that in later times we have at least
_three_ systems used contemporaneously.
I know of no specimens of lierne vaulting more charming than what we see
in the oriels of the halls of Crosby Hall (Fig. 386), and Eltham Palace
(Fig. 387), two sister works, unquestionably the work of the same
architect, in the reign of Edward IV. They are of different plans. The
one consists of five sides of an octagon, the other of a double square.
The latter is on the system I have mentioned as having its central
compartment raised like a square dome, to allow of the passage of the
arch by which it opens into the hall. Both are carried out with the
depressed arch belonging to their late period, and are treated with
exquisite care and taste.
At Gloucester, in the choir, and Winchester, in the nave, this manner of
vaulting assumes a very peculiar form; the side cells falling in at a
low level, as what are called “_Welsh_” groins, leaving a width of
barrel-vault above, which is richly decorated by surface ribs and
liernes.
[Illustration: Fig. 386.--Oriel, Crosby Hall, London.]
That at Gloucester is a work of extraordinary magnificence. Its great
specialty lies in its having two sets of diagonal ribs (Fig. 388), the
one on the ordinary system, the other comprising two bays each, and by
their intersection defining the position of the “_Welsh_” groins. Thus
the whole of the ordinary diagonal ribs, and half of the others, become
mere ornamented mouldings on the surface of the barrel-vault, while to
them is added a vast network of liernes, cutting it into an infinity of
panels, whose angles are marked by a perfect army of carved bosses. The
same was imitated at a later period in the Lady Chapel.
[Illustration: Fig. 387.--Oriel, Eltham Palace, Kent.]
[Illustration: Fig. 388.--Gloucester Cathedral. Choir Vaulting.]
In many cases, as in the western portals at Winchester, the upper
portion of the groining assumes forms in which the lines of the true
ribs seem almost forgotten. This is done to a very vicious extent in the
choir at Wells. I may mention, as a late example of this manner of
vaulting, an exquisitely beautiful chamber adjoining the cloister at
Windsor.
During this period two practices crept into use, to which it is not easy
to assign precise dates, but which worked great changes in the art of
vaulting. The one is the use--especially at first for diagonal ribs--of
a curve drawn from two centres, which gradually brought down the arches
to excessively low proportions. The other practice was the use of
portions of the same curve for several, or even all, of the ribs, either
throughout their height, or at least for their lower part. The
first-named custom was very natural in cases where the height of the
vaults was limited by circumstances, as in St. Stephen’s crypt. The
diagonal ribs here were struck from three centres to the double rib, and
in the next ribs from two to each single rib, and were also slightly
segmental; that is to say, that they made an angle with the vertical
line. They may be said to be a sort of imitation of the ellipse, as also
is the case with the diagonals in the vaulting of the south and west
cloisters at Westminster.
The other practice (_i.e._ the repetition of the same curve for
different ribs) is very curious and important in its results. It
influenced in an extraordinary degree the _plan_ of the vaulting at its
intermediate heights. Professor Willis has called special attention to
these half-height plans, as a matter of much importance to the effect.
If vaulting were carried out on perfect theoretical principles, and with
the level ridge, these plans would be _rectangular_. The mere
substitution of circular curves, unless made a little segmental, softens
the angle of the square, while any modification of these curves produces
its effect, one way or another, on this half-height plan. Professor
Willis has illustrated this in a very interesting manner from the
variations found in the cloisters at Norwich; a work generally of
uniform design, but which, having been carried out at several different
periods, the habits of the masons had undergone changes which produced
very curious effects in this respect.
I may mention that where the ribs are of the same curve the ridges
cannot be level; but that the use of the two-centred curve enabled them
to repeat the same curve, for the springers, but slightly to change it
above by varying the position of the centre, from which the upper part
of the curve is struck, so as to make the ridges level where it was
desired.
This tendency to the repetition of the same curve led to the development
of a most remarkable variety in vaulting, which especially characterised
its later history in this country. I allude to that extraordinary form
known as _Fan_ vaulting.
It is self-evident that if a number of ribs of equal curvature spring at
equal angles from a single pillar, the plan of the vault at any level
will be a circle or a portion of a circle; and that they may be bounded
at the level of their apex, or at any other level, by a circular
moulding, forming the whole into a figure which I have had occasion to
mention as having been generated at a very different date and from
another cause, in the Norman vaulting of the circular Chapter-house at
Worcester,[60] a figure which I have defined as a concave-sided conoid,
and likened to the flower of a convolvulus.
[Illustration: Fig. 389.]
[Illustration: Fig. 390.]
Now, the vaulting of any space, if set out in square compartments, and
having ribs of similar curvature and at equal distances, may be formed
into a number of portions of this figure by merely drawing semicircles
and quadrants, as the case may be, from apex to apex of the surrounding
arches (Fig. 389).
A remainder of the ordinary vaulting, with rising ridges, exists,
however, above this extemporised fan, and the whole has to be dealt with
artistically on a system suited to the new form.
The general idea of such treatment of a fan or conoid may be said to be
parallel to that of a circular or rose window. The ribs are viewed as
radiating mullions, and are made to multiply in number as the circle
expands, and usually to terminate round the outer boundary with a series
of tracery forms like the heads of two-light windows. A good rose-window
of late date, if imagined to be elastic, and drawn out from its centre
into a conoidal form, would make a good compartment of fan groining; or
a groining fan compressed into a plane would make a good rose-window.
The interstices between the fans are filled up in various ways; either
by circles of somewhat similar design, which sometimes drop down in
little pendent fans, like stalactites from the roof of a cavern; or with
a number of circles fitted together; or by continuing the diagonal ribs
to their intersection with the ridges, and filling in the triangular
spaces with tracery.
It is not, however, essential that the compartments so dealt with should
be _square_ in plan. If _oblong_, the semicircles or quadrants are drawn
from the apex of the narrower and lower arches; and from the same
centres portions of circles are drawn from the apex of the wider and
higher arches, assuming the form of an additional or outer zone of a
rose-window, and intersecting on the line of the cross ridges, and thus
forming a portion cut out of a great fan (Fig. 390). Or the roof may be
described as being formed of very large fans intersecting one another.
Such is the famous roof of King’s College Chapel, at Cambridge, but the
frustums of fans are there bisected by vast transverse ribs, which were,
no doubt, required for strength, owing to the great scale of the
vaulting (Fig. 391).
[Illustration: Fig. 391. King’s College, Cambridge.]
The earliest instance which is known of fan vaulting is in the cloisters
at Gloucester, dating from the beginning of the fifteenth century;
indeed, Professor Willis thinks the invention due to a school of masons
there. It, contrary to the usual practice, is formed with simple arches,
instead of four centres. Each fan has but the transverse and wall ribs
at its springing. At the next stage it forms the diagonal, then two
intermediate ribs, and finally four more on each side of the transverse
rib, and ends in little two-light window-like heads, while the space
above is filled with four large cusped arches, and as many pear-shaped
figures (Fig. 392).
[Illustration: Fig. 392.--Cloisters, Gloucester Cathedral.]
The limits of my lecture will not permit me to follow up this part of my
subject as its importance demands; and my means of producing
illustrations (for which I have heartily to thank several zealous and
talented gentlemen engaged in my office, as well as one of my sons) have
exhausted themselves before this laborious phase is reached.
I have already referred to the Gloucester cloisters and King’s College
Chapel.
The central compartment or crossing of St. George’s, Windsor, is a most
magnificent treatment of an oblong space. The aisles of the same chapel,
with the smaller chapels adjoining, are charming examples, as are the
aisles and small chapels of Henry VII.’s Chapel, and the cloisters of
St. Stephen’s, Westminster. Bath Abbey and Sherborne Minster are thus
vaulted, and a whole century later, appearing long after date, comes the
beautiful ceiling of the staircase to the hall at Christ Church, Oxford
(Fig. 393), a square space groined on a central pillar (Fig. 394).
[Illustration: Fig. 393. Ceiling of the Staircase to the Hall, Christ
Church, Oxford.]
[Illustration: Fig. 394.]
In the construction of the vaulting of these later periods, we have a
curious instance of the manner in which extremes meet. In the earliest
specimens of vaulting, all the strength lies in the vaulting surface
itself. As time went on, ribs were introduced, one after another, to
strengthen and support it, till at length they amounted to a permanent
framework of stone, centering on which the vaulting surface lay.
Now, at length, time has its revenge, and the extreme multiplication of
ribs led to the loss of their uses; the whole, or nearly the whole,
being cut out of the same blocks with the panels; and thus the original
system was reverted to; the vaulting surface becoming again the entire
structure, and the ribs and panels simply cut as ornaments out of its
substance.
The most remarkable production of the fan system of vaulting is the
gorgeous central roof of Henry VII.’s Chapel, a work in which
ingenuity, perplexity, and beauty are united in the most wonderful
manner which can be conceived.
Though it stands quite alone in point of intricacy and magnificence, it
is not the first instance of the use of the peculiar system on which it
is founded. How Fuller could have attributed its origin to the foreign
studies of the King and Bishop Fox, it is difficult to conceive; for,
not only is fan groining itself a purely English invention, but the
special system of _this_ roof has, so far as I know, only English
prototypes.
The earliest of these is the vaulting of the Divinity School at
Oxford,[61] finished about 1480. This was subsequently imitated, though
with the loss of its leading principle, in the choir of the Cathedral
(then the Church of St. Fridewide’s Convent in the same city), a work
which, though popularly attributed to Wolsey, is probably of earlier
date.
I have often looked in vain for the leading principle on which this
wonderful work was designed. Its _construction_ is plain enough; the
difficulty is the ideal of its _design_. Like everything, however, which
is founded on reason, its idea once perceived, it becomes perfectly
simple, and one then only wonders where the difficulty lay.
It was simply as follows:--First imagine, for argument’s sake, that the
architect had intended to divide his space into three spans--a wide and
two narrow ones--like the Lady Chapel at Salisbury, or the crypt of the
Sainte Chapelle at Paris, supporting the vaulting on ranges of thin
pillars (Fig. 395). The setting out of the divisions was about the
following. The whole span being divided into five parts, two were given
to the width of a bay, one to the imaginary aisle, and three to the
central span. The vaulting of the aisles, then, would be in oblongs of
double their width _set lengthway_ of the building, and the central span
in oblongs half as long again as their width _set crossway_ to the
building.
[Illustration: Fig. 395.]
Let us apply to each the rule I have already laid down for the fan
vaulting of oblongs. Beginning with the ideal aisles, from the pillars
and responds and centres draw the lower circles of the fans reaching the
apex of the _narrower_ arches, and the upper circles reaching the apex
of the _wider_ arch (Fig. 396). This gives us an oblong fan vault in its
most normal form.
[Illustration: Fig. 396.]
Then do precisely the same with the wider or central span, and our space
is covered with oblong fan vaulting of the most usual kind. Now, as the
lower arch of the central span is identical with the higher arch of the
side spans, it follows that the fans in the sides (or aisles) are
continued and completed in the central vault, the lower arch of the
small vault being also continued round to complete the design. The
decoration of the smaller fans then is in _two_ stages, and that of the
larger ones in _three_; but, the design of both being continuous, the
one is only an extension of the other.
Had the architect stopped here, no system of vaulting, on the fan
principle, or space so divided, could be more systematic or more simple
in its ideal.
He had no thought, however, of stopping at so commonplace a stage, and
his pillars were designed only to do their work on paper, and then to be
erased. The columns were omitted, and their places supplied by pendants;
but, as such a roof could not stand for a moment, something must be done
to supply the support which the pillars would have afforded.
[Illustration: Fig. 397.--Henry VII’s Chapel, Westminster Abbey.]
This was effected by the introduction of strong transverse arches
crossing the whole chapel, and springing much lower than the vaulting
(Fig. 397). These crossed the narrower spans, striking arbitrarily into
their fans, and uniting themselves with the central vaulting. The
pendants are not to be looked upon as constructionally interfering with
these transverse arches, as they become, in fact, part of them, and the
arches may be supposed to pass through them in an imaginary line, so
that, as in the case of the Lady Chapel at Caudebec, the pendant is in
reality a voussoir, the greater portion of which hangs down below the
face of the vaulting; the small arches upwards towards the wall help to
strengthen and weight the transverse arches at their weakest part.
[Illustration: Fig. 398.--Divinity Schools, Oxford.