524 BRICK 



kilns may be economised and a great outlay saved in steam-pipes, boilers, and 

 attention. It must not be forgotten, also, that so largo an atmospheric condensor as 

 the steam-chamber is not heated without a considerable expenditure in fuel. This 

 drying by steam is a great stride in advance of the old fiued shed ; but practical men 

 must see the immense loss incurred constantly from this source of the spent heat of the 

 burning kilns, and that by economising it, an immense saving will be effected in the 

 manufacture. The kilns are constructed as near the lower end of these chambers as 

 convenient." 



A kiln for attaining tho object of the one built in 1846 by Mr. Chamberlain is 

 worked at Epson; but with this difference, that the smoke is consumed. Tho 

 drying shed is kept quite close, that tho hot flues may raise the temperature 

 so high as to dry the ware. In this kiln the heated gases escape from tho top, after 

 passing up through tho ware, into flues, and are carried to the ground, and 

 thence into the drying shed, which is a very large construction in proportion 

 to the size of the kiln, and ' holds nearly sufficient ware to fill four kilns. In 

 this shed the heat passes up a hollow wall, about six feet high, and after running 

 through the length of the shed on one side, returns down similar flues on the opposite 

 side of the shed, and is again carried to the kiln, through the bottom of which it passes 

 in two close flues between the three kiln-furnaces, with the exception of small aper- 

 tures, through which the heat enters to consume the smoke. From these return flues 

 the spent gases rise up a shaft at. the end of the kiln. One result of carrying these 

 return flues through the kiln, is the attaining a great draft or suction in the flues to 

 carry off vapour. 



The common brick kiln is a rectangular building, generally open, but sometimes 

 arched over. In the side walls and opposite to each other, are built fireplaces, or 

 holes for the insertion of the fuel. The furnaces are formed in the setting of the 

 kiln with unburnt bricks, and above these the kiln is filled as above described. In 

 these kilns, from the raw ware forming the furnace, the flash of the flame, from the 

 fires of the walk, too often vitrefies and destroys the nearest bricks. In the open 

 kiln, as the fire or heat reaches to the top, the fireman soils or earths it down, which 

 throws the draft to another part more backward ; and, as it continues to rise, he pro- 

 ceeds with this operation until all the top is earthed in ; he then continues the firing 

 until the whole has sunk, by the contraction of the clay in the fire, to the desired 

 depth. The fire-holes are then stopped up with mud, and the kiln is left to cool 

 gradually. If the air were admitted too rapidly while the kiln was at this intense 

 heat, it would cause bricks, made with strong clays, to fly to pieces like glass ; it is, 

 in fact, the process of annealing, Cooling too quickly also affects, in many clays, 

 the colour of the bricks. 



Temporary kilns are constructed in the country, with unburnt bricks, and called 

 clamps. In Staffordshire, the bricks are burnt in small round kilns, called ovens 

 which hold from 7,000 to 8,000 bricks each ; these are burnt from fire in tho walls 

 round the ovens, and tho raw ware is set in, so as to form a flue from each fire, to 

 direct the flame to the centre. These ovens burn very quickly, and a most intense 

 heat can be obtained in them. Mr. Chamberlain must be again quoted on tho burn- 

 ing of bricks : 



'I will now more fully describe a principle of burning which I have had in 

 practice for the last six years, and which I can therefore recommend with great con- 

 fidence. The great object in brick-making is to attain a sufficient heat to thoroughly 

 burn the ware with as small a consumption of coal as possible ; and with nearly an 

 equal distribution of the heat over all parts, so that the whole of the ware, being 

 subjected to the same temperature, may contract equally in bulk, and be of one 

 uniform colour throughout. The advantage is also gained of burning in much less 

 time than in the old kilns, which, on an average, took a week ; and the management 

 is so simplified that a^y man, even though not at all conversant with the manufacture, 

 after he has soon one kiln burnt, will be able to manage another ; and the last, though 

 not least, advantage is, that of delivering up to us the waste heat at the ground level, 

 or under the floor of the kiln, to be used in drying the green ware, or in partially 

 burning the next kiln. 



' Hitherto the heat has been applied by a series of fireplaces, or flues and openings 

 round the kiln, each exposed to the influence of the atmosphere ; and in boisterous 

 weather it is very difficult to keep the heat at all regular, the consequence of which 

 is, the unequal burning we often see. The improvements sought by experimentalists 

 have been the burning the goods equally, and, at the same time, more economically. 

 These are obtained by the patent kilns, as improved by Mr. Eobert Scrivener, of 

 Shelton, in the Staffordshire Potteries. The plan is both simple and effective, and is 

 as follows : A furnace is constructed in the centre of the kiln, much below tho floor 

 level, and BO built that the heat can be directed to any part of the Mln at the pleasure 



