Bricks have always the shape of parallelopipeds of three unequal dimensions bearing a certain relation to one another. Ancient bricks were larger than those of the present day and their dimensions did not bear the same relation to one another. At the present time the width is generally about half the length, and the thickness about half the width.

The latter dimension should not exceed .12 m., so that one may take up in the hand a brick laid flat; the thickness does not exceed .07 m. on account of drying, which would be too slow, and scarcely ever is less than .05 m., except in special cases.

The object of the relation between the length and breadth of bricks is to facilitate dressing. Brick walls, in fact, are divided into partitions, the thickness of which varies from that of one brick laid on edge or flat in the direction of the width or length, the junction being crossed, and walls of one or several bricks' breadth: a brick and a half, two bricks and a half, etc.

These methods of dressing make the work easier and increase the solidity of the masonry; they can only give good results with a brick of very regular shape, especially as regards thickness, for the layers must be of the same height.

The table below gives the dimensions of the principal types employed in different countries.

The dimensions given are those most generally found, but special bricks are manufactured for special uses. For example, some have only half the usual length, and are: .11 x . 11 x .06; they are used for making joints without having to cut a brick in two; others have only half the usual thickness (.22 x .11 x .03), and are used for cellar partitions or to make up a difference of level; and finally, the bricks called "closoirs," .22 x .055 x .055, have only half the breadth of ordinary bricks. When the bricks are less than .055 m. thick they are called "briquettes." Briquettes exist of 2, 3, 4, and 5 centimetres in thickness. The brick-maker may of course manufacture any brick which lightens labour, and builders often find it advantageous to use it, even when more expensive, to avoid the always burdensome expense of cutting, and to improve the workmanship.

 Dimensions in Centimetres. Price per 1000. Remarks. Name of Country. Length. Breadth. Thickness. Cubic Content. France Marseilles brick . 21.5 IO.5 5-7 I2IO-1694 (1) In Paris, the bricks of .055 are reserved for facades, and the thicker ones for interiors. In certain buildings, briquettes of less than .05 thickness are used. Clinkers are used for paving yards and stables. Burgundy „ 22 II 5.5 1331 Paris ,, 22 II 6-7 I452-1694 Type Union Cera-mique 22 IO.5 5.5 I270 „ NorthernArchitects 22 10.5 6 1386 ,, Clinkers 16 6 4 384 Germany ,, Normal 25 12 6.5 1950 England ,, Minimum . 23.6 11.5 7.6 2040 The cubic content of the mortar used in brick masonry varies from 10 to so per cent, of the total volume, according to the care used in making the joints. ,, Maximum . 25.4 12.4 7.6 2390 Austria „ Normal 25 12 6.5 I950 Belgium ,, Kleynestern 3.5 5 3.5 6l ,, Derdeling . 15 7.3 3.8 416 „ Papesteen . 18 8.5 4.5 688 „ Klampstebi. 19 9 4.7 761 ,, Gand . 22 11 6 1452 Holland .... 26 12 5.4 1684 Switzerland, Normal type 25 12 6.5 1950 United States . . . 19.5 9.8 5 980

(1) Below are some catalogue prices; they are capable of reduction, and are for goods taken at the factory.

 Weight. Price. Burgundy Montchanin 2.7 k. 60 fr. stamped. Perrusson... 65 fr. „ Champagne Gilardoni freres 2.5 k. 35 fr. hand-made. 40 fr. die-made. Normandy Argences 1.9k. 48 fr. ordinary. 55 fr. stamped. Rouen (no reduction) 2.5 k. 21 fr. hand-made. 28 fr. stamped. Paris Brault... 2.6 k. 55 fr. stamped. Muller... 2.5k. 50 fr. ,. Radot .... 2.6 k. 60 fr ,,

## Shapes

Ordinary bricks, as we have stated, are in the form of parallelopipeds with the dimensions above shown, but for special purposes bricks of special shapes are made, and the principal examples of these are shown in Figs. 234 to 257.

The ordinary shape (Fig. 234) is naturally the one most generally used. Conical bricks called "coin" (Fig. 235) are used for arches whose surface is solely formed of ends; for those into which only sides enter, bricks called "couteau" are taken (Fig. 236).

For the beginning of arches the bricks have only one inclined face. This inclination of the faces bears a relation to the radius of the arch.

The outside embrasures of doors and even of windows are made with bricks one edge of which is more or less rounded (Figs. 239, 254).

For entrance pillars, or to decorate the coping of a wall, bricks are used having one (Fig. 237) or two corners (Fig. 238) cut.

Bricks with moulded profiles (Figs. 240 to 250) are used in coping enclosure walls, in house cornices, garden borders, etc.

The masonary of wells or fully arched vaults requires to be economical and well made, bricks of the arched shape shown in Fig- 253.

For large factory chimneys, bricks are used of the shape of that in Fig. 257. Finally, paving bricks have hollows or ribs on their surface to prevent slipping in walking on them (Figs. 251, 252).

The manufacture of these bricks is performed in the same way as that of ordinary bricks, the dies having the shape required; the bricks are most frequently stamped with presses whose moulds are of the desired size and shape. Each kind of brick therefore requires a special die and mould which can only be used for that class of brick. If, then, the manufacturer has a certain number of types, he must have a considerable stock of apparatus which is only used to make annually a limited number of bricks. The amortisation, interest, and maintenance of this stock will raise the cost of these special bricks all the more, as the consumption of them is small.

Figs. 234 to 257. Bricks of Various Shapes.