CHAMBERS'S INFORMATION FOR THE PEOPLE. 



expose the masses to the mellowing action of the 

 winter air and frost. The next process is temper- 

 ing the clay, that is, preparing it in the form of a 

 homogeneous paste for the moulder. This is still 

 effected in many districts by hand, turning it over 

 and over, and treading it with horses or men. In 

 the improved processes, tempering is effected by 

 the use of revolving rollers, between which the 

 clay is passed ; or by what is termed a pug-mill. 

 This consists of an upright conical tub, the small 

 end downwards ; in which a shaft, fitted with 

 projecting knives or cutters, is made to revolve 

 by horse-power. The knives knead and cut the 

 clay, and force it through the bottom of the mill, 

 where it is cut into lumps, and laid aside till 



Fig. i. 



required. Fig. I shews an improved form of pug- 

 mill, known as Clayton's Archimedean knife pug- 

 mill. Great care is taken at the outset to free the 

 clay from all stones, pebbles, &c. ; the presence of 

 one of which, even of small dimensions, will cause 

 the brick to crack in drying. 



The next process is the moulding. The mould 

 consists of a frame the size of the brick, without 

 top or bottom, as aa, 

 fig. 2. In the improved 

 form of solid bricks, 

 indentations, as c, are 

 made in the upper and 

 under faces of the 

 brick (b, fig. 2). These 

 form a 'key' to the 

 mortar, securing effi- 

 cient bond. To form 

 this indentation, pro- 

 jections are made in the bottom of the mould and 

 in the top. The moulder works at a bench ; and 

 his art consists in dashing in a lump of the 

 tempered clay so as completely to fill up the 

 mould, the superfluous clay being dexterously 

 taken off with what is called the strike. To pre- 

 vent the clay adhering to the mould, it is either 

 dipped in water, or sprinkled with sand : if the 

 latter, it is termed ' pallet-moulding ; ' if the former, 

 ' slop-moulding.' In slop-moulding, two moulds 

 are required, ' as the mould with its newly made 

 brick is carried off by the attendant boy to the 

 drying-ground, where the brick is deposited, the 



354 



Fig. 2. 



moulder the while forming another brick in a 

 second mould, which is finished by the time the 

 boy returns with the first. 



In pallet-moulding, one mould alone is used, 

 the bricks being turned out on a pallet when made, 

 and taken by the boy in a hack-barrow to the 

 drying-floor. By slop-moulding, a man can make 

 10,000 per week ; while by pallet-moulding, he 

 can make as many as 36,000 ; in the latter case, 

 however, the moulder has an assistant. 



The next process, or that of drying, is one 

 which requires considerable attention. ' The great 

 point,' says Mr Dobson, ' to be aimed at is to pro- 

 tect them against sun, wind, rain, and frost, and 

 to allow each brick to dry uniformly from the 

 face to the heart.' The drying is sometimes 

 effected under cover ; but more frequently the 

 ' hacks ' are built in the open air, and covered 

 with various substances, as straw, tarpaulin, &c. 



The last process is the burning, which is per- 

 formed either in kilns or in clamps the latter 

 being large square piles of bricks skilfully built 

 up, with layers of fuel between, called breeze, and 

 also with flues filled with coal, cinders, and wood, 

 to facilitate still more the process of combustion. 

 Baking in kilns, however, is preferable, as there 

 is not only less waste, and less fuel consumed, 

 but the bricks are sooner ready for the market. 

 'The kiln/ says Dr Ure, 'is usually 13 feet long 

 by 10^ feet wide, and about 12 feet in height. 

 The walls are one foot two inches thick, carried 

 up a little out of the perpendicular, inclining 

 towards each other at the top. The 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 con- 

 tinues two or three days before they are ready for 

 burning, which is known by the smoke turning 

 from a darkish colour to transparent. The mouth 

 or mouths of the kiln are now dammed up with 

 pieces of bricks piled one upon another, and closed 

 with wet brick-earth, leaving above it just /oom 

 sufficient to receive a fagot. The fagots are made 

 of furze, heath, brake, fern, &c. and the kiln is 

 supplied with these until its arches look white, 

 and the fire appears at the top ; upon which the 

 fire is slackened for an hour, and the kiln allowed 

 gradually to cool. This heating and cooling are 

 repeated until the bricks are thoroughly burned, 

 which is generally done in forty-eight hours. One 

 of these kilns will hold about 20,000 bricks.' 



Clamp-dried bricks require to be thoroughly 

 dried previous to burning. Where kilns are used, 

 the heat can be regulated so nicely that compara- 

 tively damp bricks may be put in, which are first 

 dried by a gentle heat. In the clamp, as the heat 

 is got up almost immediately, it would cause damp 

 bricks to fly in pieces. 



Slowly, machinery is superseding the hand- 

 making of bricks, and it is more than probable 

 that it would have completely done so long ere 

 this but for the trade combinations of the work- 

 men. Time, however, will bring this desirable 

 change about, and bricks will then be produced 

 at a cost far less than at present, and with extra- 

 ordinary rapidity and superior excellence. A 

 brick-making machine, made and worked by Mr 

 Platt of Oldham, turns out ready for the kilns 

 140,000 bricks per week. The principle of brick- 

 making by machinery differs considerably, from 





