Chapter XV: Part 15

_Seasoning Stone._--Stone freshly quarried is full of sap, and thus
admits of being easily worked. On being exposed to the air the sap
dries out, and the stone becomes much harder in consequence. For this
reason, and because carriage charges are lessened by the smaller bulk
of the worked stone as compared with the rough block, the stone for a
building is often specified to be quarry-worked. Vitruvius recommended
that stone should be quarried in summer when driest, and that it
should be seasoned by being allowed to lie two years before being
used, so as to allow the natural sap to evaporate. In the erection of
St Paul's Cathedral, Sir Christopher Wren required that the stone
after being quarried should be exposed for three years on the
sea-beach before its introduction into the building.

The regular and determined form of bricks makes it to a large extent a
matter of practice to enable a man to become a good bricklayer, but
beyond these a continual exercise of judgment is required of the
workman in stone, who has for the most part to deal with masses of all
forms and of all sizes.

_Setting Stones._--All beds and joints should be truly worked and
perfectly level. If the surface be convex it will give rise to wide
unsightly joints; if concave the weight thrown on the stone will rest
on the edges and probably cause them to "flush" or break off and
disfigure the work. Large stones are placed in position with the aid
of hoisting appliances and should be tried in position before being
finally set. Great care should be taken to avoid fracturing or
chipping the stone in the process of handling, as it is impossible to
make good such damage. All stratified stones--and this includes by far
the largest proportion of building stones--when set in a level
position should be laid on their natural bed, i.e. with their laminae
horizontal. The greatest strength of a stone is obtained when the
laminae lie at right angles to the pressure placed upon it. In the
case of arches these layers should be parallel with the centre line of
the voussoirs and at right angles to the face of the arch. For
cornices (except the corner-stones) and work of a like nature, the
stone is set with the laminae on edge and perpendicular to the face of
the work. With many stones it is easy to determine the bed by
moistening with water, when the laminae will become apparent. Some
stones, however, it is impossible to read in this way, and it is
therefore advisable to have them marked in the quarry. A horizontal
line in a quarry does not in all cases give the proper bed of the
stone, for since the deposits were made ages ago natural upheavals
have possibly occurred to alter the "lie" of the material.

For the shafts of columns especially it is necessary to have the
layers horizontally placed, and a stone should be selected from a
quarry with a bed of the required depth. An example of the omission of
this precaution is visible in the arcading of the Royal Courts of
Justice, London, where the small shafts of the front arcade in red
sandstone have been turned with the laminae in a vertical position,
with the result that nearly every shaft is flaking away or is cracked.

_Use of Mortar._--See BRICKWORK. Of whatever quality the stone may be
of which a wall is built, it should consist as much of stone and as
little of mortar as possible. Only fine mortar is admissible if we are
to obtain as thin joints as possible. The joints should be well raked
out and pointed in Portland cement mortar. This applies only to some
sandstones, as marbles and many limestones are stained by the use of
Portland cement. For these a special cement must be employed, composed
of plaster of Paris, lime, and marble or stone-dust.

_Bonding._--Bond (see BRICKWORK) is of not less importance in stone
walling than in brickwork. In ashlar-work the work is bonded
uniformly, the joints being kept perpendicularly one over the other;
but in rubble-work, instead of making the joints recur one over the
other in alternate courses they should be carefully made to lock, so
as to give the strength of two or three courses or layers between a
joint in one course and the joint that next occurs vertically above it
in another course. In the through or transverse bonding of a wall a
good proportion of header stones running about two-thirds of the
distance through the width of the wall should be provided to bind the
whole structure together. The use of through stones, i.e. stones
running through the whole thickness of the wall from front to back, is
not to be recommended. Such stones are liable to fracture and convey
damp to the internal face.

_Slip Joints._--As with brickwork so in masonry great care must be
exercised to prevent the different parts of a building settling
unequally. When two portions of a building differing considerably in
height come together, it is usual to employ a slip or housed joint
instead of bonding the walls into each other. This arrangement allows
the heavier work to settle to a greater extent than the low portion
without causing any defect in the stones.

_Footings._--The footings of stone walls should consist of large
stones of even thickness proportionate to their length; if possible
they should be the full breadth in one piece. Each course should be
well bedded and levelled.

_Walling._--There are broadly speaking two classes of stone walling:
rubble and ashlar. Rubble walls are built of stones more or less
irregular in shape and size and coarsely jointed. Ashlar walls are
constructed of carefully worked blocks of regular dimensions and set
with fine joints.

_Random Rubble_ (fig. 3) is the roughest form of stonework. It is
built with irregular pieces of stone usually less than 9 in. thick,
loosely packed without much regard to courses, the interstices between
the large stones being occupied by small ones, the remaining crevices
filled up with mortar. Bond stones or headers should be used
frequently in every course. This form of walling is much used in stone
districts for boundary walls and is often set dry without mortar. For
this work the mason uses no tool but the trowel to lay on the mortar,
the scabbling hammer to break off the most repulsive irregularities
from the stone, and the plumb-rule to keep his work perpendicular.

_Coursed Rubble_ (fig. 4) is levelled up in courses 12 or 18 in. deep,
the depth varying in different courses according to the sizes of the
stones. The stones are dressed by the workman before he begins
building, to obtain a fairly level bed and perpendicular face.

_Irregularly Coursed Squared Rubble_ is a development of uncoursed
random rubble, the stones in this case being squared with the hammer
and roughly faced up with the axe. The courses jump abruptly from one
level to another as the sizes of the blocks demand; the interstices
are filled in with small pieces of stone called "snecks."

For _Coursed Squared Rubble_ the stone is faced in a similar manner
and set in courses, the depth of each course being made up of one or
more stones.

In _Regular Coursed Rubble_ all the stones in one course are of the
same height.

_Block-in-course_ is the name applied to a form of stone walling that
has some of the characteristics of ashlar but the execution of which
is much rougher. The courses are usually less than 12 in. high. It is
much used by engineers for waterside and railway work where a good
appearance is desired.

The _Angles_ or _Quoins_ of rubble-work are always carefully and
precisely worked and serve as a gauge for the rest of the walling.
Frequently the quoins and jambs are executed in ashlar, which gives a
neat and finished appearance and adds strength to the work.

The name _Ashlar_ is given, without regard to the finish of the face
of the stone, to walling composed of stones carefully dressed, from 12
to 18 in. deep, the mortar joints being about an eighth of an inch or
less in thickness. No stone except the hardest should exceed in length
three times its depth when required to resist a heavy load and its
breadth should be from one and a half to three times its depth. The
hardest stone may have a length equal to four or perhaps five times
its depth and a width three times its depth. The face of ashlar-work
may be plain and level, or have rebated, chamfered, or moulded joints.

Backing to Stonework.

The great cost of this form of stonework renders the employment of a
backing of an inferior nature very general. This backing varies
according to the district in which the building operations are being
carried on, being rubble stonework in stone districts and brick or
concrete elsewhere, the whole being thoroughly tied together both
transversely and longitudinally with bondstones. In England a stone
much used for backing ashlar and Kentish rag rubble-work is a soft
sandstone called "hassock." In the districts where it is quarried it
is much cheaper than brickwork. (For brickbacking see BRICKWORK.)
Ashlar facing usually varies from 4 to 9 in. in thickness. The work
must not be all of one thickness, but should vary in order that
effective bond with the backing may be obtained. If the work is in
courses of uneven depth the narrow courses are made of the greater
thickness and the deep courses are narrow. It is sometimes necessary
to secure the stone facing back with iron ties, but this should be
avoided wherever possible, as they are liable to rust and split the
stonework. When it is necessary to use them they should be covered
with some protective coating. The use of a backing to a stone wall,
besides lessening the cost, gives a more equable temperature inside
the building and prevents the transmission of wet by capillary
attraction to the interior, which would take place if single stones
were used for the entire thickness.

All work of this description must be executed in Portland cement,
mortar of good strength, to avoid as much as possible the unequal
settlement of the deep courses of stone facing and the narrower
courses of the brick or rough stone backing. If the backing is of
brick it should never be less than 9 in. thick, and whether of stone
or brick it should be levelled up in courses of the same thickness as
the ashlar.

Walling.

There are many different sorts of walling, or modes of structure,
arising from the nature of the materials available in various
localities. That is perhaps of most frequent occurrence in which
either squared, broken, or round flints are used. This, when executed
with care, has a distinctly decorative appearance. To give stability
to the structure, lacing courses of tiles, bricks or dressed stones
are introduced, and brick or stone piers are built at intervals, thus
forming a flint panelled wall. The quoins, too, in this type of wall
are formed in dressed stone or brick work.

Uncoursed rubble built with irregular blocks of ragstone, an
unstratified rock quarried in Kent, is in great favour for facing the
external walls of churches and similar works (fig. 5).

_Pointing._--As with brickwork this is generally done when the work is
completed and before the scaffolding is removed. Suitable weather
should be chosen, for if the weather be either frosty or too hot the
pointing will suffer. The joints are raked out to a depth of half an
inch or more, well wetted, and then refilled with a fine mortar
composed specially to resist the action of the weather. This is
finished flat or compressed with a special tool to a shaped joint, the
usual forms of which are shown in fig. 6.

_Stonewash._--To give a uniform appearance to the stonework and
preserve the finished face until a hardened skin has formed, it is
usual to coat the surface of exposed masonry with a protective
compound of ordinary limewhite with a little size mixed in it, or a
special mixture of stone-dust, lime, salt, whiting and size with a
little ochre to tone it down. After six months or more the work is
cleaned down with water and stiff bristle or wire brushes. Sometimes
muriatic acid much diluted with water is used.

_Technical Terms._--Of the following technical terms, many will be
found embodied in the drawing of a gable wall (fig. 7), which shows
the manner and position in which many different members are used.

_Apex Stone._--The topmost stone of a gable forming a finial for the
two sloping sides; it is sometimes termed a "saddle" (fig. 7).

_Blocking Course,_ a heavy course of stone above a cornice to form a
parapet and weigh down the back of the cornice (fig. 8).

_Bed._--The _bed_ surface upon which a stone is set or bedded should
be worked truly level in every part. Many workmen to form a neat thin
joint with a minimum amount of labour hollow the bed and thus when the
stone is set all weight is thrown upon the edges with the frequent
result that these are crushed.

_Coping._--The _coping_ or _capping_ stones are placed on the top of
walls not covered by a roof, spanning their entire width and throwing
off the rain and snow, thus keeping the interior of the wall dry. The
fewer the number of joints the better the security, and for this
reason it is well to form copings with as long stones as possible. To
throw water off clear, and prevent it from running down the face of
the wall, the coping should project an inch or two on each side and
have a throat worked on the under-side of the projections (fig. 7).

_Cornice,_ a projecting course of moulded stone crowning a structure,
forming a cap or finish and serving to throw any wet clear of the
walls. A deep drip should always be worked in the upper members of a
cornice to prevent the rain trickling down and disfiguring the face of
the moulding and the wall below (fig. 8).

_Corbel,_ a stone built into a wall and projecting to form a
cantilever, supporting a load beyond the face of the wall. It is
frequently richly ornamented by carving (fig. 7).

_Skew Corbel,_ a stone placed at the base of the sloping side of a
gable wall to resist any sliding tendency of the sloping coping.
Stones placed for a similar purpose at intervals along the sloping
side, tailing into the wall, are termed "kneelers" and have the
section of the coping worked upon them (fig. 7).

_Corbel Table,_ a lino of small corbels placed at short distances
apart supporting a parapet or arcade. This forms an ornamental feature
which was much employed in early Gothic times. It probably originates
from the machicolations of ancient fortresses.

_Dressings,_ the finished stones of window and door jambs and quoins.
For example, a "brick building with stone dressings" would have brick
walls with stone door and window jambs, heads and sills, and perhaps
also stone quoins (fig. 7).

_Diaper,_ a square pattern formed on the face of the stonework by
means of stones of different colours and varieties or by patterns
carved on the surface (fig. 7).

_Finial,_ a finishing ornament applied usually to a gable end (fig.
7).

_Gablet,_ small gable-shaped carved panels frequently used in Gothic
stonework for apex stones, and in spires, &c.

_Gargoyle,_ a detail, not often met with in modern work, which
consists of a waterspout projecting so as to throw the rain-water from
the gutters clear of the walls. In early work it was often carved into
grotesque shapes of animal and other forms.

_Galleting._--The joints of rubble are sometimes enriched by having
small pebbles or chips of flint pressed into the mortar whilst green.
The joints are then said to be "galleted."

_Jamb._--Window and door jambs should always be of dressed stone, both
on account of the extra strength thus gained and in order to give a
finish to the work. The stones are laid alternately as stretchers and
headers; the former are called outbands, the latter inbands (fig. 7).

_Label Moulding,_ a projecting course of stone running round an arch.
When not very large it is sometimes cut on the voussoirs, but is
usually made a separate course of stone. Often, and especially in the
case of door openings, a small sinking is worked on the top surface of
the moulding to form a gutter which leads to the sides any water that
trickles down the face of the wall.

_Lacing Stone._--This is placed as a voussoir in brick arches of wide
span, and serves to bond or lace several courses together (see
BRICKWORK).

_Lacing Course,_ a course of dressed stone, bricks or tiles, run at
intervals in a wall of rubble or flint masonry to impart strength and
tie the whole together (fig. 7).

_Long and Short Work,_ a typical Saxon method of arranging quoin
stones, flat slabs and long narrow vertical stones being placed
alternately. Earls Barton church in Northamptonshire is an example of
their use in old work. In modern work long and short work, sometimes
termed "block and start," is little used (fig. 7).

_Parapet,_ a fence wall at the top of a wall at the eaves of the roof.
The gutter lies behind, and waterways are formed through the parapet
wall for the escape of the rain-water.

_Plinth,_ a projecting base to a wall serving to give an appearance of
stability to the work.

_Quoin,_ the angle at the junction of two walls. Quoins are often
executed in dressed stone (fig. 7).

_Rag-bolt,_ the end of an iron bolt when required to be let into stone
is roughed or ragged. A dovetailed mortise is prepared in the stone
and the ragged end of the bolt placed in this, and the mortise filled
in with molten lead or sand and sulphur (fig. 9).

_Sill,_ the stone which forms a finish to the wall at the bottom of an
opening. Sills should always be weathered, slightly in the case of
door sills, more sharply for windows, and throated on the under side
to throw off the wet. The weathering is not carried through the whole
length of the sill, but a stool is left on at each end to form a
square end for building in (fig. 7).

_String Courses,_ horizontal bands of stone, either projecting beyond
or flush with the face of the wall and often moulded or carved. They
are frequently continuations of the sills or head lines of windows
(figs. 5 and 7).

_Scontion._--In a thick wall the dressed stones forming the inside
angles of the jamb of a window or door opening are termed scontions.

_Spalls,_ small pieces chipped off whilst working a stone.

_Templates,_ slabs of hard stone set in a wall to take the ends of a
beam or girder so as to distribute the load over a larger area of the
wall.

_Tympanum,_ the triangular filling of masonry in a pediment between
the cornices, or between the horizontal head of a window or door and
the under-side of the relieving arch above it. It is often panelled or
enriched with carved ornament (fig. 7).

_Throat,_ a groove worked on the under-side of projecting external
members to intercept rain-water and cause it to drop off the member
clear of the work beneath (fig. 8).

_Weathering._--The surface of an exposed stone is weathered when it is
worked to a slope so as to throw off the water. Cornices, copings,
sills and string courses should all be so weathered.

_Voussoirs,_ the wedge-shaped blocks of which an arch is built up.

_Methods of finishing Face of Stones._--The _self face_ or _quarry
face_ is the natural surface formed when the stone is detached from
the mass in the quarry or when a stone is split.

_Saw-face,_ the surface formed by sawing.

_Hammer-dressed, Rock-faced, or Pitch-faced._--This face is used for
ashlar-work, usually with a chisel-draughted margin around each block.
It gives a very massive and solid appearance to the lower storeys of
masonry buildings, and is formed with little labour, and is therefore
the cheapest face to adopt for ashlar-work (fig. 7).

_Broached and Pointed Work._--This face is also generally used with a
chisel-draughted margin. The stone as left from the scabbling hammer
at the quarry has its rocky face worked down to an approximate level
by the point. In broached work the grooves made by the tool are
continuous, often running obliquely across the face of the block. In
pointed work the lines are not continuous; the surface is rough or
fine pointed according as the point is used over every inch or
half-inch of the stone. The point is used more upon hard stones than
soft ones (fig. 7).

_Tooth-chiselled Work._--The cheapest method of dressing soft stones
is by the toothed chisel which gives a surface very much like the
pointed work of hard stones.

_Droved Work._--This surface is obtained with a chisel about two and a
half inches wide, no attempt being made to keep the cuts in continuous
lines.

_Tooled Work_ is somewhat similar to droved work and is done with a
flat chisel, the edge of which is about four inches wide, care being
taken to make the cuts in continuous lines across the width of the
stone.

_Combed or Dragged Work._--For soft stones the steel comb or drag is
often employed to remove all irregularities from the face and thus
form a fine surface. These tools are specially useful for moulded
work, as they are formed to fit a variety of curves.

_Rubbed Work._--For this finish the surface of the stone is previously
brought with the chisel to a level and approximately smooth face, and
then the surface is rubbed until it is quite smooth with a piece of
grit stone aided by fine sand and water as a lubricant. Marbles are
polished by being rubbed with gritstone, then with pumice, and lastly
with emery powder.

Besides these, the most usual methods of finishing the faces of
stonework, there are several kinds of surface formed with hammers or
axes of various descriptions. These types of hammers are more used on
the continent of Europe and in America perhaps than in England, but
they deserve notice here.

The _toothed axe_ has its edges divided into teeth, fine or coarse
according to the work to be done. It is used to reduce the face of
limestones and sandstones to a condition ready for the chisel. The
_bush hammer_ has a heavy square-shaped double-faced head, upon which
are cut projecting pyramidal points. It is used to form a surface full
of little holes, and with it the face of sand and limestones may be
brought to a somewhat ornamental finish. The _patent hammer_ is used
on granite and other hard rocks, which have been first dressed to a
medium surface with the point. The fineness of the result is
determined by the number of blades in the hammer, and the work is said
to be "six," "eight" or "ten-cut" work according to the number of
blades inserted or bolted in the hammer head. The _crandall_ has an
iron handle slotted at one end with a hole 3/8 in. wide and 3 in.
long. In this slot are fixed by a key ten or eleven double-headed
points of ¼ in. square steel about 9 in. long. It is used for
finishing sandstone and soft stones after the surface has been
levelled down with the axe or chisel. It gives a fine pebbly sparkling
appearance.

There are several methods of finishing stone which involve a great
deal of labour and are therefore expensive to work, but which result
in imparting a very stiff and unnatural appearance to the masonry.

_Vermiculated Work._--This is formed by carving a number of curling
worm-like lines over the face of the block, sinking in between the
worms to a depth of a fourth of an inch. The surface of the strings is
worked smooth, and the sinkings are pock-marked with a pointed tool
(fig. 7).

_Furrowed Work._--In this face the stone is cut with a chisel into a
number of small parallel grooves or furrows (fig. 7).

_Reticulated Face_ is a finish somewhat similar to vermiculated work,
but the divisions are more nearly squares.

_Face Joints of Ashlar._--The face joints of ashlar stonework are
often sunk or rebated to form what are termed rusticated joints;
sometimes the angles of each block are moulded or chamfered to give
relief to the surface or to show a massive effect (fig. 7).

_Joints in Stonework._--The joints between one block of stone and
another are formed in many ways by cramps, dowels and joggles of
various descriptions.

Cramps.

The stones of copings, cornices and works of a similar nature, are
often tied together with metal cramps to check any tendency for the
stones to separate under the force of the wind (figs. 10 and 11).
Cramps are made of iron (plain or galvanized), copper or gun-metal, of
varying sections and lengths to suit the work. A typical cramp would
be about 9 in. long, 1 or 1½ in. wide, and from ¼ to ½ in. thick, and
turned down about 1½ in. at each end. A dovetailed mortise is formed
at a suitable point in each of the stones to be joined and connected
by a chase. The cramp is placed in this channel with its turned-down
ends in the mortises, and it is then fixed with molten lead, sulphur
and sand, or Portland cement. Lead shrinks on cooling, and if used at
all should be well caulked when cold. Double dovetailed slate cramps
bedded in Portland cement are occasionally used (fig. 11).

Dowels.

Dowels are used for connecting stones where the use of cramps would be
impracticable, as in the joints of window mullions, the shafts of
small columns, and in similar works (figs. 7, 8 and 20). Dowels for
bed and side joints may be used. They are of slate, metal, or
sometimes of hard wood.

Joggles.

There are many ways of making a joggle joint. The joggle may be worked
on one of the stones so as to fit into a groove in the adjoining
stone, or grooves may be cut in both the stones and an independent
joggle of slate, pebbles, or Portland cement fitted, the joggle being
really a kind of dowel. The pebble joggle joint is formed with the aid
of pebbles as small dowels fitted into mortises in the jointing faces
of two stones and set with Portland cement; but joggles of slate have
generally taken the place of pebbles. Portland cement joggles are
formed by pouring cement grout into a vertical or oblique mortise
formed by cutting a groove in each of the joining surfaces of the
stones. What is known as a he-and-she joggle, worked on the edges of
the stones themselves, is shown in fig. 13.

Plugs or dowels of lead are formed by pouring molten lead through a
channel into dovetailed mortises in each stone (figs. 14 and 15). When
cold the metal is caulked to compress it tightly into the holes.

The saddle joint is used for cornices, and is formed when a portion of
the stone next the joint is left raised so as to guide rain-water away
from the joint (fig. 8).

Two forms of rebated joints for stone copings and roofs are common. In
one form (shown in fig. 7) the stones forming the coping are thicker
at their lower and rebated edge than at the top plain edge, giving a
stepped surface. The other form has a level surface and the stone is
of the same thickness throughout and worked to a rebate on top and
bottom edges. In laying stone roofs the joints are usually lapped over
with an upper slab of stone.

_Joints in Spires._--Four forms of jointing for the battering
stonework of spires are shown in fig. 16. A is a plain horizontal
joint. B is a similar joint formed at right angles to the face of the
work. This is the most economical form of joint, the stone being cut
with its sides square with each other; but if the mortar in the joint
decay moisture is allowed to penetrate. With these forms dowelling is
frequently necessary for greater stability. The joints C and D are
more elaborate and much more expensive on account of the extra labour
involved in working and fitting.

Where a concentrated weight is carried by piers or columns the bed
joints are in many cases formed without the use of mortar, a thin
sheet of milled lead being placed between the blocks of stone to fill
up any slight inequalities.

_Moulded Work._--The working of mouldings in stone is an important
part of the mason's craft, and forms a costly item in the erection of
a stone structure. Much skill and care is required to retain the
arrises sharp and the curved members of accurate and proportionate
outline. As in the case of wood mouldings, machinery now plays an
important part in the preparation of stone moulded work. The process
of working a stone by hand labour is as follows: The profile of the
moulding is marked on to a zinc template on opposite ends of the stone
to be worked; a short portion, an inch or two in length termed a
"draught," is at each end worked to the required section. The
remaining portion is then proceeded with, the craftsman continually
checking the accuracy of his work with a straight-edge and zinc
templates. A stone to be moulded by machinery is fixed to a moving
table placed under a shaped tool which is fixed in an immovable
portion of the machine, and is so adjusted as to cut or chip off a
small layer of stone. Each time the stone passes under the cutter it
is automatically moved a trifle nearer, and thus it gradually reduces
the stone until the required shape is attained.

_Iron in Stonework._--The use of iron dowels or cramps in stonework,
unless entirely and permanently protected from oxidation is attended
by the gravest risks; for upon the expansion of the iron by rusting
the stone may split, and perhaps bring about a more or less serious
failure in that portion of the building. A case in point is that of
the church of St Mary-le-Strand, London, where the ashlar facing was
secured to the backing with iron cramps; these were inefficiently
protected from damp, with the result that many of the blocks have been
split in consequence of rusting. John Smeaton in his Eddystone
Lighthouse used dowels of Purbeck marble.

_Stone Arches._--Stone arches are very frequently used both in stone
and brick buildings. (For general definitions and terms see
BRICKWORK.) They may be built in a great variety of styles, either
flat, segmental, circular, elliptical or pointed. Each block or
voussoir should be cut to fit exactly in its appointed place, the
joints being made as fine as possible. The joints should radiate from
the centre from which the soffit or intrados is struck, or in the case
of an elliptical arch they should be at right angles to a tangent
drawn to the intrados at that point. The extrados or back of the arch
is usually concentric with the intrados, but is sometimes made thicker
in one portion than in another; thus the arch may be deeper at the
crown than at the sides, or at the sides than in the centre. In some
cases two or more voussoirs are of one stone, having a false joint cut
in the centre; this is economical, and in some cases adds to the
stability of the arch. Generally the arch is divided into an uneven
number of voussoirs so as to give a keystone, the voussoirs being laid
from each side of the keystone and fitting exactly in the centre of
the arch. The keystone is not a necessity, arches being frequently
formed with an even number of voussoirs; some architects hold that the
danger of the voussoirs cracking is thereby lessened. Where lintels
are used in a stone wall over openings of small span it is usual to
build a relieving arch above to take the superincumbent weight of
masonry; or the same purpose may be effected in walls of ashlar by a
flat relieving or "save" arch, formed in the next course of three
stones above the lintel, the tapering keystone resting between the two
side stones which are tailed well into the wall.

In very many cases it is desired to form square heads to openings of
greater span than it is convenient to obtain lintels for in one piece,
and some form of flat arch must therefore be adopted. The voussoirs
are connected by joggles worked on their joints, as in fig. 17. The
weight of the superimposed wall is taken by a lintel with relieving
arch above at the back of the arch.

Arches built to an elliptical form when used for large spans (if of
flat curve they should bridge over 8 ft. or 10 ft.) are liable if
heavily loaded to fail by the voussoirs at the centre being forced
down, or else to burst up at the haunches. With arches of this
description there is a large amount of outward thrust, and abutments
of ample strength must be placed to receive the springers.

_Stone Tracery._--The designs of Gothic and other tracery stonework
are almost infinite, and there are many methods, ingenious and
otherwise, of setting out such work. Nearly all diagrams of
construction are planned on the principle of geometrical
intersections. In the example illustrated in fig. 18 the method of
setting out and finishing the design is very clearly shown, together
with the best positions for the joints of the various parts. The
jointing is a matter which must be carefully considered in order to
avoid any waste of stone and labour. It will be observed that the
right-hand side of the elevation shows the method of setting out the
tracery by the centre lines of the various intersecting branches, the
other half giving the completed design with the cusping drawn in and
the positions of joints. All the upper construction of windows and
doors and of aisle arches should be protected from superincumbent
pressure by strong relieving arches above the labels, as shown in the
figure, which should be worked with the ordinary masonry, and so set
that the weight above should avoid pressure on the fair work, which
would be liable to flush or otherwise destroy the joints of the
tracery.

_Carving._--Stone carving is a craft quite apart from the work of the
ordinary stonemason, and like carving in wood needs an artistic
feeling and special training. Carving-stone should be of fine grain
and sufficiently soft to admit of easy working. The Bath stones in
England and the Caen stone of France are largely used for internal
work, but if for the exterior they should be treated with some
chemical preservative. Carving is frequently done after the stone is
built into position, the face being left rough--"boasted"--and
projecting sufficiently for the intended design.

See E. Viollet-le-Duc, _Dictionnaire raisonné de l'architecture
française_; W. R. Purchase, _Practical Masonry_; J. O. Baker, _A
Treatise on Masonry Construction_; C. F. Mitchell, _Brickwork and
Masonry_; W. Diack, _The Art of Masonry in Britain_. (J. Bt.)

FOOTNOTE:

[1] The English word "mason" is from the French, which appears in the
two forms, _machun_ and _masson_ (from the last comes the modern Fr.
form _maçon_, which means indifferently a bricklayer or mason). In O.
H. Ger. the word is _mezzo_, which survives in the German for a
stone-mason, _Steinmetz_. The med. Lat. form, _machio_, was connected
with _machina_--obviously a guess. The Low Lat., _macheria_ or
_maceria_ (see Du Cange, _Glossarium_, s.v. _macio_), a wall, has
been suggested as showing some connexion. Some popular Lat. form as
_macio_ or _mattio_ is probably the origin. No Teut. word, according
to the _New English Dictionary_, except that which appears in
"mattock," seems to have any bearing on the ultimate origin.

MASPERO, GASTON CAMILLE CHARLES (1846- ), French Egyptologist, was born in Paris on the 23rd of June 1846, his parents being of Lombard origin. While at school he showed a special taste for history, and when fourteen years old was already interested in hieroglyphic writing. It was not until his second year at the École Normale in 1867 that Maspero met with an Egyptologist in the person of Mariette, who was then in Paris as commissioner for the Egyptian section of the exhibition. Mariette gave him two newly discovered hieroglyphic texts of considerable difficulty to study, and, self-taught, the young scholar produced translations of them in less than a fortnight, a great feat in those days when Egyptology was still almost in its infancy. The publication of these in the same year established his reputation. A short time was spent in assisting a gentleman in Peru, who was seeking to prove an Aryan affinity for the dialects spoken by the Indians of that country, to publish his researches; but in 1868 Maspero was back in France at more profitable work. In 1869 he became a teacher (_répétiteur_) of Egyptian language and archaeology at the École des Hautes Études; in 1874 he was appointed to the chair of Champollion at the Collège de France.

In November 1880 Professor Maspero went to Egypt as head of an archaeological mission despatched thither by the French government, which ultimately developed into the well-equipped Institut Français de l'Archéologie Oriental. This was but a few months before the death of Mariette, whom Maspero then succeeded as director-general of excavations and of the antiquities of Egypt. He held this post till June 1886; in these five years he had organized the mission, and his labours for the Bulak museum and for archaeology had been early rewarded by the discovery of the great cache of royal mummies at Deir el-Bahri in July 1881. Maspero now resumed his professorial duties in Paris until 1899, when he returned to Egypt in his old capacity as director-general of the department of antiquities. He found the collections in the Cairo Museum enormously increased, and he superintended their removal from Gizeh to the new quarters at Kasr en-Nil in 1902. The vast catalogue of the collections made rapid progress under Maspero's direction. Twenty-four volumes or sections were already published in 1909. The repairs and clearances at the temple of Karnak, begun in his previous tenure of office, led to the most remarkable discoveries in later years (see KARNAK), during which a vast amount of excavation and exploration has been carried on also by unofficial but authorized explorers of many nationalities.

Among his best-known publications are the large _Histoire ancienne des
peuples de l'Orient classique_ (3 vols., Paris, 1895-1897, translated
into English by Mrs McClure for the S.P.C.K.), displaying the history
of the whole of the nearer East from the beginnings to the conquest by
Alexander; a smaller _Histoire des peuples de l'Orient_, 1 vol., of
the same scope, which has passed through six editions from 1875 to
1904; _Études de mythologie et d'archéologie égyptiennes_ (Paris,
1893, &c.), a collection of reviews and essays originally published in
various journals, and especially important as contributions to the
study of Egyptian religion; _L'Archéologie égyptienne_ (latest ed.,
1907), of which several editions have been published in English. He
also established the journal _Recueil de travaux relatifs à la
philologie et à l'archéologie égyptiennes et assyriennes_; the
_Bibliothèque égyptologique_, in which the scattered essays of the
French Egyptologists are collected, with biographies, &c.; and the
_Annales du service des antiquités de l'Égypte_, a repository for
reports on official excavations, &c.

Maspero also wrote: _Les Inscriptions des pyramides de Saqqaroh_
(Paris, 1894); _Les Momies royales de Deir el-Baharî_ (Paris, 1889);
_Les Contes populaires de l'Égypte ancienne_ (3rd ed., Paris, 1906);
_Causeries d'Égypte_ (1907), translated by Elizabeth Lee as _New Light
on Ancient Egypt_ (1908).

MASS (O.E. _maesse_; Fr. _messe_; Ger. _Messe_; Ital. _messa_; from eccl. Lat. _missa_), a name for the Christian eucharistic service, practically confined since the Reformation to that of the Roman Catholic Church. The various orders for the celebration of Mass are dealt with under LITURGY; a detailed account of the Roman order is given under MISSAL; and the general development of the eucharistic service, including the Mass, is described in the article EUCHARIST. The present article is confined (1) to the consideration of certain special meanings which have become attached to the word Mass and are the subject of somewhat acute controversy, (2) to the Mass in music.

The origin of the word _missa_, as applied to the Eucharist, is obscure. The first to discuss the matter is Isidore of Seville (_Etym._ vi. 19), who mentions an "evening office" (_officium vespertinum_), a "morning office" (_officium matutinum_), and an office called _missa_. Of the latter he says: "Missa tempore sacrificii est, quando catechumeni foras mittuntur, clamante levita 'si quis catechumenus remansit, exeat foras.' Et inde 'missa,' quia sacramentis altaris interesse non possunt, qui nondum regenerati sunt" ("The _missa_ is at the time of the sacrifice, when the catechumens are sent out, the deacon crying, 'If any catechumen remain, let him go forth.'" Hence _missa_, because those who are as yet unregenerate--i.e. unbaptized--may not be present at the sacraments of the altar). This derivation of the word Mass, which would connect it with the special formula of dismissal still preserved in the Roman liturgy--_Ite, missa est_--once generally accepted, is now disputed. It is pointed out that the word _missa_ long continued to be applied to any church service, and more particularly to the lections (see Du Cange for numerous examples), and it is held that such services received their name of _missal_ from the solemn form of dismissal with which it was customary to conclude them; thus, in the 4th century _Pilgrimage of Etheria_ (_Silvia_) the word _missa_ is used indiscriminately of the Eucharist, other services, and the ceremony of dismissal. F. Kattenbusch (Herzog-Hauck, _Realencyklop. s._ "Messe") ingeniously, but with little evidence, suggests that the word may have had a double origin and meaning: (1) in the sense of _dimissio_, "dismissal"; (2) in that of _commissio_, "commission," "official duty," i.e. the exact Latin equivalent of the Greek [Greek: leitourgia] (see LITURGY), and hence the conflicting use of the term. It is, however, far more probable that it was a general term that gradually became crystallized as applying to that service in which the dismissal represented a more solemn function. In the narrower sense of "Mass" it is first found in St Ambrose (_Ep._ 20, 4, ed. Ballerini): "Missam facere coepi. Dum offero ..." which evidently identifies the _missa_ with the sacrifice. It continued, however, to be used loosely, though its tendency to become proper only to the principal Christian service is clear from a passage in the 12th homily of Caesarius, bishop of Arles (d. 542): "If you will diligently attend, you will recognize that _missae_ are not celebrated when the divine readings are recited in the church, but when gifts are offered and the Body and Blood of the Lord are consecrated." The complete service (_missa ad integrum_), the bishop goes on to say, cannot be had at home by reading and prayer, but only in the house of God, where, besides the Eucharist, "the divine word is preached and the blessing is given to the people."

Whatever its origin, the word Mass had by the time of the Reformation been long applied only to the Eucharist; and, though in itself a perfectly colourless term, and used as such during the earlier stages of the 16th century controversies concerning the Eucharist, it soon became identified with that sacrificial aspect of the sacrament of the altar which it was the chief object of the Reformers to overthrow. In England, so late as the first Prayer-book of Edward VI., it remained one of the official designations of the Eucharist, which is there described as "The Supper of the Lorde and holy Communion, commonly called the Masse." This, however, like the service itself, represented a compromise which the more extreme reformers would not tolerate, and in the second Prayer-book, together with such language in the canon as might imply the doctrine of transubstantiation and of the sacrifice, the word Mass also disappears. That this abolition of the word Mass, as implying the offering of Christ's Body and Blood by the priest for the living and the dead was deliberate is clear from the language of those who were chiefly responsible for the change. Bishops Ridley and Latimer, the two most conspicuous champions of "the new religion," denounced "the Mass" with unmeasured violence; Latimer said of "Mistress Missa" that "the devil hath brought her in again"; Ridley said: "I do not take the Mass as it is at this day for the communion of the Church, but for a popish device," &c. (_Works_, ed. Parker Soc., pp. 121, 120), and again: "In the stead of the Lord's holy table they give the people, with much solemn disguising, a thing which they call their mass; but in deed and in truth it is a very masking and mockery of the true Supper of the Lord, or rather I may call it a crafty juggling, whereby these false thieves and jugglers have bewitched the minds of the simple people ... unto pernicious idolatory" (ib. p. 409). This language is reflected in the 31st of the Articles of Religion of the Church of England: "Wherefore the sacrifices of Masses, in which it was commonly said that the Priest did offer Christ for the quick and the dead, to have remission of pain and guilt, were blasphemous fables and dangerous deceits." Clearly the word Mass had ceased to be a colourless term generally applicable to the eucharistic service; it was, in fact, not only proscribed officially, but in the common language of English people it passed entirely out of use except in the sense in which it is defined in Johnson's Dictionary, i.e. that of the "Service of the Romish Church at the celebration of the Eucharist." In connexion with the Catholic reaction in the Church of England, which had its origin in the "Oxford Movement" of the 19th century, efforts have been made by some of the clergy to reintroduce the term "Mass" for the Holy Communion in the English Church.

See Du Cange, _Glossarium_, s.v. "Missa"; F. Kattenbusch in
Herzog-Hauck, _Realencyklopädie_ (ed. 1903), s.v. "Messe,
dogmengeschichtlich"; for the facts as to the use of the word "Mass"
at the time of the Reformation see the article by J. H. Round in the
_Nineteenth Century_ for May 1897. (W. A. P.)

MASS, IN MUSIC: 1. _Polyphonic Masses._--The composition of musical settings of the Mass plays a part in the history of music which is of special importance up to and including the 16th century. As an art-form the musical Mass is governed to a peculiar degree by the structure of its text. It so happens that the supremely important parts of the Mass are those which have the smallest number of words, namely the _Kyrie_, important as being the opening prayer; the _Sanctus_ and _Benedictus_, embodying the central acts and ideas of the service; and the _Agnus Dei_, the prayer with which it concludes. The 16th-century methods were specially fitted for highly developed music when words were few and embodied ideas of such important emotional significance or finality that they could be constantly repeated without losing force. Now the texts of the _Gloria_ and _Credo_ were more voluminous than any others which 16th-century composers attempted to handle in a continuous scheme. The practical limits of the church service made it impossible to break them up by setting each clause to a separate movement, a method by which 16th-century music composers contrived to set psalms and other long texts to compositions lasting an hour or longer. Accordingly, Palestrina and his great contemporaries and predecessors treated the _Gloria_ and _Credo_ in a style midway in polyphonic organization and rhythmic breadth between that of the elaborate motet (adopted in the _Sanctus_) and the homophonic reciting style of the Litany. The various ways in which this special style could be modified by the scale of the work, and contrasted with the broader and more elaborate parts, gave the Mass (even in its merely technical aspects) a range which made it to the 16th-century composer what the symphony is to the great instrumental classics. Moreover, as being inseparably associated with the highest act of worship, it inspired composers in direct proportion to their piety and depth of mind. Of course there were many false methods of attacking the art-problem, and many other relationships, true and false, between the complexity of the settings of the various parts of the Mass and of motets. The story of the action of the council of Trent on the subject of corruption of church music is told elsewhere (see MUSIC and PALESTRINA); and it has been recently paralleled by a decree of Pope Pius X., which has restored the 16th-century polyphonic Mass to a permanent place in the Roman Catholic Church music.

2. _Instrumental Masses in the Neapolitan Form._--The next definite stage in the musical history of the Mass was attained by the Neapolitan composers who were first to reach musical coherence after the monodic revolution at the beginning of the 17th century. The fruit of their efforts came to maturity in the Masses of Mozart and Haydn. By this time the resources of music were such that the long and varied text of the _Gloria_ and _Credo_ inevitably either overbalanced the scheme or met with an obviously perfunctory treatment. It is almost impossible, without asceticism of a radically inartistic kind, to treat with the resources of instrumental music and free harmony such passages as that from the _Crucifixus_ to the _Resurrexit_, without an emotional contrast which inevitably throws any natural treatment of the _Sanctus_ into the background, and makes the _Agnus Dei_ an inadequate conclusion to the musical scheme. So unfavourable were the conditions of 18th-century music for the formation of a good ecclesiastical style that only a very small proportion of Mozart's and Haydn's Mass music may be said to represent their ideas of religious music at all. The best features of their Masses are those that combine faithfulness to the Neapolitan forms with a contrapuntal richness such as no Neapolitan composer ever achieved. Thus Mozart's most perfect as well as most ecclesiastical example is his extremely terse Mass in F, written at the age of seventeen, which is scored simply for four-part chorus and solo voices accompanied by the organ with a largely independent bass and by two violins mostly in independent real parts. This scheme, with the addition of a pair of trumpets and drums and, occasionally, oboes, forms the normal orchestra of 18th-century Masses developed or degenerated from this model. Trombones often played with the three lower voices, a practice of high antiquity surviving from a time when there were soprano trombones or _cornetti_ (_Zincken_, a sort of treble _serpent_) to play with the sopranos.

3. _Symphonic Masses._--The enormous dramatic development in the symphonic music of Beethoven made the problem of the Mass with orchestral accompaniment almost insoluble. This makes it all the more remarkable that Beethoven's second and only important Mass (in D, _Op._ 123) is not only the most dramatic ever penned but is, perhaps, the last classical Mass that is thoughtfully based upon the liturgy, and is not a mere musical setting of what happens to be a liturgic text. It was intended for the installation of Beethoven's friend, the archduke Rudolph, as archbishop of Olmütz; and, though not ready until two years after that occasion, it shows the most careful consideration of the meaning of a church service, no doubt of altogether exceptional length and pomp, but by no means impossible for its unique occasion. Immense as was Beethoven's dramatic force, it was equalled by his power of sublime repose; and he was accordingly able once more to put the supreme moment of the music where the service requires it to be, viz. in the _Sanctus_ and _Benedictus_. In the _Agnus Dei_ the circumstances of the time gave him something special to say which has never so imperatively demanded utterance since. Europe had been shattered by the Napoleonic wars. Beethoven read the final prayer of the Mass as a "prayer for inward and outward peace," and, giving it that title, organized it on the basis of a contrast between terrible martial sounds and the triumph of peaceful themes, in a scheme none the less spiritual and sublime because those who first heard it had derived their notions of the horror of war from living in Vienna during its bombardment. Critics who have lived in London during the relief of Mafeking have blamed Beethoven for his realism.

Schubert's Masses show rather the influence of Beethoven's not very impressive first Mass, which they easily surpass in interest, though they rather pathetically show an ignorance of the meaning of the Latin words. The last two Masses are later than Beethoven's Mass in D and contain many remarkable passages. It is evident from them that a dramatic treatment of the _Agnus Dei_ was "in the air"; all the more so, since Schubert does not imitate Beethoven's realism.