BRICK 525 



of the fireman. First, the heat is directed up a tube in tho centre to the top of the 

 oven or kiln, and, as there is no escape allowed to take place there, it is drawn down 

 through the goods by the aid of flues in connection with a chimney. Thus, all tho 

 caloric generated in the furnace is made use of, and, being central, is equally diffused 

 throughout the mass ; but, towards the bottom, or over the exit flues, the ware would 

 not be suflicionly burnt without reversing the order of firing. In order to meet this 

 requirement there is a series of flues under the bottom, upon which the goods are 

 placed, with small regulators at the end of each ; these regulators, when drawn back, 

 allow the fire to pass under the bottom, and to rise up among the goods which are not 

 sufficiently fired, and thus the burning is completed. By means of these regulators 

 the heat may be obtained exactly the same throughout ; there is, therefore, a greater 

 degree of certainty in firing, and a considerable saving of fuel, 'with the entire con- 

 sumption of the smoke. From the fire or draught being under command, so as to be 

 allowed either to ascend or descend through the ware during the time of burning or 

 cooling, the waste caloric can be economised and directed through the adjoining kiln 

 in order to partially burn it, or be used in drying of the raw wares on flues or in 

 chambers. I have found the saving of fuel in these kilns, over the common kiln, 

 50 per cent. ; and to give an indea of the facility with which they can be worked, it 

 is common for my men to fill the kiln, burn, cool, and discharge it in six days.' 

 See KILN. 



In France attempts were long ago made to substitute animals and machines for the 

 treading of men's feet in the clay kneading pit ; but it was found that their schemes 

 could not replace, with advantage, human labour where it is so cheap, particularly for 

 separating the stones and heterogeneous matter, from the loam. The more it is 

 worked, the denser, more uniform, and more durable, the bricks which are made of 

 it. A good French workman, in a day's labour of 12 or 13 hours, it has been said, 

 is able to mould from 9,000 to 10,000 bricks, 9 inches long, t\ inches broad, and 2J 

 thick ; but he must have good assistants under him. In many brick-works near 

 Paris, screw presses are now used for consolidating the bricks and paving tiles in 

 their moulds. M. Molerat employed the hydraulic press for the purpose of con- 

 densing pulverised clay, which, after baking, formed beautiful bricks ; but the process 

 was too tedious and costly. An ingenious contrivance for moulding bricks mechani- 

 cally is said to be employed near Washington, in America. This machine moulds 

 30,000 in a day's work of 12 hours, with the help of one torse, yoked to a gin- 

 wheel, and the bricks are so dry when discharged from their moulds, as to be ready 

 for immediate burning. The machine is described, with figures, in the ' Bulletin de 

 la Soci&e" d'Encouragement,' for 1819. 



Mechanical Brick Moulding. Messrs. Lyne and Stainford obtained, in August 

 1825, a patent for a machine for making a considerable number of bricks at one 

 operation. It consists, in the first place, of a cylindrical pug-mill of the kind usually 

 employed for comminuting clay for bricks and tiles, furnished with rotatory knifes, 

 or cutters, for breaking the lumps and mixing the clay with the other materials of 

 which bricks are commonly made. Secondly, of two movable moulds, in each of 

 which fifteen bricks are made at once ; these moulds being made to travel to and fro 

 in the machine for the purpose of being alternately brought under the pug-mill to 

 be filled with the clay, and then removed to situations where plungers are enabled 

 to act upon them. Thirdly, in a contrivance by which the plungers are made to 

 descend, for the purpose of compressing the material and discharging it from the 

 mould in the form of bricks. Fourthly, in tho method of constructing and working 

 trucks which carry the receiving boards, and conduct the bricks away as they are 

 formed. 



Fig. 254 exhibits the general construction of the apparatus ; both ends of which 

 being exactly similar, little more than half the machine is represented, a is the 

 cylindrical pug-mill, shown partly in section, which is supplied with the clay and 

 other materials from a hopper above ; b b are the rotatory knives or cutters, which 

 are attached to the vertical shaft, and, being placed obliquely, press the clay down 

 towards the bottom of the cylinder, in the act of breaking and mixing it as the shaft 

 revolves. The lower part or the cylinder is opened ; and immediately under it the 

 mould is placed in which the bricks are to be formed. These moulds run to and 

 fro upon ledges in the side frames of the machine ; one of the moulds only can be 

 shown by dots in the figure, tho side rail intervening : they are situated at c c, 

 and are formed of bars of iron crossing each other, and encompassed with a frame. 

 The mould resembles an ordinary sash window in its form, being divided into 

 rectangular compartments (fifteen are proposed in each) of the dimensions of the 

 intended bricks, but sufficiently deep to allow the material, after being considerably 



gessed in the mould, to leave it, when discharged, of the usual thickness of a common 

 ick. 



