522 BRICK 



to crack ; and even if they should not bo sufficiently large to do this in drying, during 

 tho firing of the bricks there is a still further contraction of tho clay, and an expan- 

 sion of the stone from tho heat to which it is subjected, and the result is generally a 

 faulty or broken brick, and on being drawn from the kilns, the bricks are found to bo 

 imperfect. 



The clay, being sufficiently kneaded, it is brought to the bench of tho moulder, 

 who works it into a mould made of wood or iron, and strikes off the superfluous 

 matter. The bricks are next delivered from tho mould, and ranged on tho ground ; 

 and when they have acquired sufficient firmness to bear handling, they are dressed 

 with a knife, and stacked or built up in long dwarf walls, thatched over, and left to 

 dry. An able workman will make, by hand, 5,000 bricks in a day. 



The different kinds of bricks made in England are principally place bricks, grey and 

 red stocks, marl facing bricks, and cutting bricks. The place bricks and stocks are used 

 in common walling. Tho marls are made in the neighbourhood of London, and used 

 in the outside of buildings, they are very beautiful bricks, of a fine yellow colour, 

 hard, and well burnt, and, in every respect, superior to the stocks. The finest kind 

 of marl and red bricks, called cutting bricks, are used in the arches over windows and 

 doors, being rubbed to a centre, and gauged to a height. 



Bricks, in this country, are generally baked either in a clamp or in a kiln. The 

 latter is the preferable method, as less waste arises, less fuel is consumed, and the 

 bricks are sooner burnt. The kiln is usually 13 feet long, by lOAfeet wide, and about 

 12 feet in height. The walls are one foot two inches thick, carried up a little out of 

 the perpendicular, inclined towards each other at the top. Tho bricks are placed on 

 flat arches, having holes left in them resembling lattice- work ; the kiln is then covered 

 with pieces of tiles and bricks, and some wood put in, to dry them with a gentle 

 fire. 



This continues two or three days before they are ready for burning, which is known 

 by the smoke turning from a darkish colour to semi-transparency. The mouth or 

 mouths of the kiln are now dammed up with a shinlog, which consists of pieces of 

 bricks piled one upon another, and closed with wet brick earth, leaving above it just 

 room sufficient to receive a fagot. The fagots are made of furze, heath, brake, fern, 

 &c., and tho kiln is supplied with these until its arches look white, and the firo 

 appears at the top ; upon which the fire is slackened for an hour, and the kiln allowed 

 gradually to cool. This heating and cooling is repeated until the bricks are thoroughly 

 burnt, which is generally done in 48 hours. One of these kilns will hold about 

 20,000 bricks. 



Clamps are also in common use. They are made of the bricks themselves, and 

 generally of an oblong form. The foundation is laid with place brick, or the driest 

 of those just made, and then the bricks to be burnt are built up, tier upon tier, as 

 high as the clamp is meant to be, with two or three inches of breeze or cinders 

 strewed between each layer of bricks, and the whole covered with a thick stratum of 

 breeze. The fire-place is perpendicular, about three feet high, and generally placed 

 at the west end ; and the flues are formed by gathering or arching the bricks over, so 

 as to leave a space between each of nearly a brick wide. Tho flues run straight 

 through the clamp, and are filled with wood, coals, and breeze, pressed closely to- 

 gether. If the bricks are to be burnt off quickly, which may be done in 20 or 30 days, 

 according as the weather may suit, tho flues should be only at about six feet distance ; 

 but if there be no immediate hurry, they may be placed nine feet asunder, and tho 

 clamp left to burn off slowly. 



The following remark* by Mr. H. Chamberlain, on the drying of bricks, have an 

 especial value from the great experience of that gentleman, and his careful observation 

 of all the conditions upon which the preparation of a good brick depends. 



' The drying of bricks ready for burning is a matter of groat importance, and re- 

 quires more attention than it generally receives. From hand-made bricks we have to 

 evaporate some 25 per cent, of water before it is safe to burn them. In a work re- 

 quiring the make of 20,000 bricks per day, we have to evaporate more than 20 tons 

 of water every 24 hours. Hand-made bricks lose in drying about one-fourth of their 

 weight, and in drying and burning about one-third. The average of machine bricks 

 those made of tho stiff plastic clay do not lose more than half the above amount 

 from evaporation, and are, therefore, of much greater specific gravity than hand-made 

 ones. 



' The artificial drying of bricks is carried on throughout the year uninterruptedly in 

 sheds having tho floor heated by fires ; but this can only be effected in districts where 

 coal is cheap. Tho floors of these sheds are a series of tunnels or flues running 

 through tho shod longitudinally. At the lower end is a pit, in which are the furnaces 

 the fire travels up the flues under the floor of the shed, giving off its heat by tho way, 

 and the smoke escapes at tho upper end, through a series of (generally three or four) 



