back to front, and must have backs." Her Majesty's Commissioners for building new churches allow 20 inches by 34 inches for each sitting; free seats 20 inches by 27 inches, and 14 inches for children. Benches for free sittings are to be 3 feet, 4 feet 6 inches, or 6 feet long. The allowance made for each sitting in St. Paul's Cathedral is, as nearly as possible, 20 inches by 33 inches. From 4 to 5 square feet of floor is not too much space to be calculated for each person, allowing for gangways, communion table, &c.

2192c. Cloisters, porches, canopies, over-doors, stall-work, lych-gates, windows, staircases, bell-wheels and carriages, luffer or louvre boards, fencing, screens, pulpits, desks, lecterns, chests, tables, cum multis aliis, are amongst the many other productions of the joiner, being far too numerous to be described in detail herein.

FORMATION OF BODIES BY JOINING THEM WITH GLUE.

2193. The way in which bodies are glued up together for different purposes will be given below, and with them will close this section.

2194. Fig. 789. shows at A a section of two boards glued up edge to edge. At B the face of the same is seen. C shows the section of two boards glued edge to edge, each piece being grooved, and a tongue inserted at their junction. By similar means a board may be increased to any width, be the pieces whereof it is composed ever so narrow. D shows two boards fixed at right angles, the edge of one being glued on the side of the other. A block for the purpose of strengthening the joint is fitted and glued to the interior side.

2195. Fig. 790. A is a section of two boards to be joined at an oblique angle. They are mitred and glued together with a block at the angle. B shows the inner sides of the boards so fixed. It is by repeating this operation that columns are glued up. 2196. Fig. 791. A is the section of an architrave.

The moulding is usually, if not

always, glued to the board; the vertical line therefore, showing the extreme boundary of

the moulded part, is the sec- A

tion of the piece to be glued, B is the face of the architrave, C and D a section and front of it before it is moulded, E a section of it with the button and nail to show the way in which the two parts are glued together, and F shows the back of the architrave with the buttons which are used for the purpose of bringing the two sur

faces to be glued together in contact, till after they are set and fully held together, being knocked off when the glue has become hard, and then the moulding shown at A and B is stuck.

courses, where the vertical joints are made to break, as seen in the elevation A. 2198. In fig. 793. is exhibited the mode in which veneers are glued together for the purpose of forming cylindrical surfaces. Brackets with their faces upwards are nailed to

a board. Their ends are perpendicular, and a cavity is left between them sufficient to receive the veneers and wedges. In A the thin part in the form of an are shows the veneers as in the state of glueing, the wedges being on the convex side. B is a section of the board and bracket. The work when putting together should be dry and warm, and the glue should be hot. When this last has set hard, the wedges must be slackened, and the

veneers, which now form a solid, taken out.

2199. Fig. 794. is a strong method of forming a concave surface by laying the veneer upon a cylinder, and backing it with blocks in the form of bricks, which are glued to the convex side of the veneers and to each other. The fibres of the blocks are to be as nearly as possible parallel to the fibres of the veneers. A is the section of the cylinder veneer and blocks, and B shows the convex side of the blocks.

2200. Fig. 795. is another mode of glueing veneers together with cross pieces screwed to a cylinder, the veneers being placed between the former and the latter.

2201. In fig. 796. is shown the method of glueing up columns in pieces, which here are eight in number, each being glued to the other after the manner of fig. 790. The workman should be careful to keep the joints out of the flutes, when the columns are to be fluted, by which the substance will be more likely to prevent the joints giving way. A is a section of the column at top, and B at the bottom. After glueing together, the octagons and mitres should be correctly laid down for the true formation of the joints. In B are shown two bevels, one

for trying the mitres. and the other for trying the work when put together.

2202. Fig. 797. is the mode of glueing up the base of a column. It is formed in three courses, the pieces in each of which are made to break joint over one another. The horizontal joints of the courses must be so adjusted as to fall at the junction of two mouldings, forming a

Fig. 798.

re-entering angle. After the glue is set quite hard, the rough base is sent to the turner, by whom it is reduced into the required profile. The fibres of the wood should lie horizontally, in which direction the work

Fig. 799

will stand much better than when they are vertical. A is the plan of the base inverted, and B is the elevation.

2203. The formation of a modern Ionic capital is given in fig. 798., wherein A is the plan inverted, showing the method of placing the blocks; and B is the elevation.

2204. Fig. 799. is the method of glueing up for the leaves of the Corinthian capital, A is the plan inverted, and B is the elevation. The abacus is glued up in the same manner as in the preceding example.

2205. Fig. 800. exhibits the mode of forming a cylindrical surface without veneers, by means of equidistant parallel grooves, A is the elevation, and B the plan.

2206. Fig. 801. exhibits the method of covering a conic body. It is, in fact, no more than covering the frustum of a cone, and is accomplished by two concentric arcs terminated at the ends by the radii. The radius of the one arc

is the whole slant side of the cone, that of the other

is the slant side of the part cut off.
the grooves are directed to the centre,
with slips of wood glued as before.
shown by the circle ABC. The arc HI must be
equal to the circumference ABC.

2207. Fig. 802. shows the same thing for a smaller segment.

2208. Fig. 803. shows the manner of glueing up a globe or sphere by the same method. A is the face of the piece; B the edge showing the depth of the grooves; C shows the mould for forming the riece to the true curvature; and D the faces of two pieces put together.

D

Fig. 806.

SECT. VI.

SLATING.

2209. An account of the materials used by the slater has been detailed in Chap. II. Sect. IX. The tools used by this artificer are the scantle, which is a gauge by which slates are regulated to their proper length; the trowel; the hammer; the zaz, an instrument for cutting the slates; a small handpick; and a hod and a board for mortar. The zax is an instrument made of tempered iron, about 16 inches long and 2 inches wide, like a large knife bent a little at one end, with a wooden handle at the other, and having a projecting piece of iron on its back, drawn to a sharp point, to make holes in the slates for the nails, the other side being used to chip and cut the slates to their required size, as when brought from the quarry they are not sufficiently square and cleaned for the slater's use. The places for the nail holes are marked usually on the slate where they have to be punched, with a gauge, and then the iron of the zar is struck through the slate. Each slate has two holes; large slates require three. A better mode of obtaining the place for the holes is to mark a plank with two small pieces of wood across it, at the distance required; the position is thus shown at once.

2210. Slating is laid in inclined courses, beginning from the eaves and working upwards, the courses nearest the ridge of the roof being less in width than those below. The lap of one slate over another is called its bond, and it is the distance between the nail of the under slate and the lower end of the upper slate. The bed of a slate is its under side, and the upper side is called its back. The part of each course which is exposed to the weather is called its gauge, bare, or margin. The slates are nailed to close or open boarding, lying on the back of the rafters, with nails, which should be of copper or zinc. If iron nails are used they should be well painted. The operation of cutting or paring the side and bottom edges of the slates is called trimming them; but the head of the slate is never cut. In that part the holes were formerly pierced by which the nails pass to the boarding. This boarding (or sarking, as it is called in the north of Great Britain) is usually inch to 1 inches thick, rough, of equal thickness, and well secured to the common rafters. A good practice obtains of bedding slates in mortar, on boarding, which gives them a sound bearing, especially if the roof will have to stand much wear from persons passing along the gutters, or over the ridge, for repairs or other purposes.

2210a. Another method of forming a roof, as lately employed by some architects, consists in slating on boards fixed to purlin-rafters, without any common rafters, as shown in figs. 695a. and 697. The purlins are placed somewhat closer than when rafters are used; the boards are 1 inches thick, usually placed diagonally. It makes very sound work, and saves height, where that may be an object. Another method, as noticed in par. 2285a., is to nail the boarding on to common rafters laid as purlins, as shown in figs. 695 and 696.

22106. The common method of slating is to nail the slates to laths or battens, as in tiling, but a house so done is more liable to be affected with the various changes from heat to cold than by the other system. These laths are cut to boards of 20, 25, 30 or 36. Thus a board 12 × 9 × 3, cut 3 deep and 4 flat, equals 1 board 20. If cut 4 deep and 4 flat, equals 1 board 25. If cut 4 deep and 5 flat, equals 1 board 30. If cut 5 deep and 5 flat, equals 1 board 36. Slating laid on battens, at places on the sea coast, and as usual in work in Ireland, is either wholly "rendered" with lime and hair on the under side, or only the under edges and laths are thus secured. Without this precaution the slates rattle, and the driving winds get under them, tending to strip the roofs. Rendering properly done, lasts as long as the slates exist in a perfect state.

2210c. Open or ventilated slating, which is nearly equally as waterproof as the usual method of slating, will save one third of the quantity per square.

2210d. Felt. Slate is also laid on felt, on 3-inch boarding. Croggon's patent asphalte roofing felt is impervious to rain, snow, and frost, and is a non-conductor. From its anticorrosive properties, it is of service when placed between iron and wood and between metals. It is manufactured of any required length, by 32 inches wide. There is some risk of dry rot occurring, however, by using it thus; the better plan is to lay the felt on boards, and then to batten for the slates over the felt, so as to leave an air space between the felt and the slates. Its general weight is about 42 lbs. per square. Patent asphaltic roofing felt is about in. thick; slaters' or sarking felt is about in. thick, as is also inodorous felt. Fibrous asphalte or foundation felt is suggested for preventing damp rising when placed above the footings of a wall; but it has some disadvantages. Nonconducting dry hair felt, in sheets 34 inches by 20 inches, is also obtainable in long lengths.

3 16

Roofing felt is specially prepared for hot climates. Non-conducting felt is formed entirely of hair, and is used for covering boilers. steam pipes, &c., for the purpose of preventing the radiation of heat. When applied to boilers, a cement of 2 parts of white lead, 1 parts of red lead, 4 parts of whiting, is mixed with boiled linseed oil; after being spread over the felt, the whole is patted down on the boiler, and in a short time the felt firmly adheres. No cement is needed for steam-pipes, the felt being wrapped round and secured by twine. Sheets of this felt are made 32 inches by 20 inches; and of the following weights:-No. 1, 16 oz.; No. 2, 24 oz.; No 3, 32 oz.; No 4, 40 oz.; No. 5, 48 oz. This dry hair or inodorous felt is also useful for deadening sound, by cutting it into 2 or 2 inch strips, and laying it on the joists under the floor boards; also as lining to walls and floors; and for lining iron houses to equalise the temperature.

2210e. Felt is also applied for forming roofs of temporary buildings. It has been suggested for permanent buildings, but to that employment of it we must withhold our approval. The rafters may be about 2 inches by 14 inches, placed 20 to 24 inches apart, laid at a pitch of 2 or 3 inches to the foot, and covered with 4-inch boarding. The felt is to be stretched tight, overlapping 1 inch at the joints, nailed with two-penny fine clout nails, first heated and cooled in grease, about 1 inches apart; copper nails are preferable. The whole roof is then to have a good coating of hot coal tar and lime, in the proportion of 2 gallons of the former to 6 pounds of the latter, well boiled together, put on with a common tar mop, and while it is soft some coarse sharp sand sifted over it. The gutters are made of two folds, cemented together with the boiling mixture. The coating to the roof must be renewed every fourth or fifth year, according to the climate. The felt is found to last better, if it be not made to adhere by any mixture to the boarding.

2210f. Felt for sheds, or occasional purposes, may be put up without boarding; the rafters in this case would not exceed 3 inches by 1 inches, placed at a distance of 30 inches apart. To prevent the felt bagging, battens, or slighter rafters, of about 2 inches by 1 inch, are placed between the others. To such roofs the felt must be laid from eaves to eaves, nailing through the overlap into the main rafter. The pitch of this roof should be about 6 inches to the foot. The "ventilated" slating will bear an economical contrast, provided the smaller size of slates be used, and is more durable.

2210g. Another modern material for roofing is Willesden paper and canvas. Two-ply paper used for underlining slates, tiles, leaky roofs; for interior lining; fixing against damp walls, under floors, and for interior decorations. It is waterproof, and does not smell. 100 square feet of it equals 164 lbs. The 1-ply paper is used for underlining, fixing against damp walls, waterproof wrapping, packing, stencil paper, &c. The canvas is water-repellant and rot-proof. The scrim is waterproof, and useful for shading green houses, ferneries, &c., and for fixing to damp walls to protect ornamental wall-papers.

2210h. Slating is sometimes laid lozengewise, but it is much less durable than when laid in the usual method. It is introduced for the sake of ornamental effect. The ends of the slates are also rounded, or cut angleways to a point, or the angles only cut off; 01, if the slates be of a small size, they are set angleways over courses with square ends. These are all shown in an excellent article in Viollet-le-Duc's Dictionnaire, s.v. Ardoise. Slating is also made to have a decorative effect by forming zigzag patterns with red coloured slates among blue slates; or a few courses of the one above a larger number of the other.

2210. James Wyatt, R.A., arranged a system for forming roofs with slate slabs without boarding or battens. In this the slates were all reduced to widths equal to the distance between centre and centre of the rafters. On the backs of these last they are screwed by two or three strong inch-and-half screws at each of their ends. Over the junctions of the slates, on the backs of the rafters, fillets of slates about two and a half or three inches wide, bedded in putty, are screwed down, to prevent the entrance of rain. The handsome regular appearance of this sort of slating gained it, at first much celebrity; but it was soon abandoned, on account of the disorder it is liable to sustain from the slightest partial settlement of the building, as well as from the constant dislodgment of the putty, upon which greatly depended its being impervious to rain.

2211. Subjoined is a succinct account of the different sorts of slates brought to the London market, and enumerated in the order of their goodness and value.

2211a. Westmoreland slates. These are from 3 feet 6 inches to 1 foot in length, and from 2 feet 6 inches to 1 foot in breadth. They should be nailed with not less than sixpenny and eight-penny copper or zinc nails (iron nails should never be used); and a ton in weight of sized slates will usually cover about two squares and a quarter. The weight of the coarsest Westmoreland is to that of common tiling as 36 to 54.

22116. Welsh rags are next in goodness, and are nearly of the same sizes as those last