FICTILE MANUFACTURES. 



the beginning, from that employed in the old and 

 rude hand process. 



The clay is brought as nearly dry as possible to 

 the machine, and fed into large hoppers, and is 

 made to pass through fluted rollers, which, whilst 

 allowing the semi-plastic material to pass between 

 them, reject all but very small stones. It is then 

 carried through long drying-cylinders by Archi- 

 medean screws, the drying being effected by a 

 powerful blast of air through the cylinders, of 

 which there are two. At the end of the first, 

 opposite to where the material entered, is another 

 set of revolving rollers, which reduce the now 

 drier lumps of clay into very small lumps, re- 

 jecting stones which were small enough to pass 

 the first set : elevators lift it to the second drying- 

 machine, after passing through which, it drops 

 on to a kind of iron mechanical sieve, which nibs 

 it into small grains, and rejects every fragment 

 of stone which has escaped the other means of 

 removal. It now passes, by means of a set of 

 elevators, to a mill, which rapidly grinds it into 

 a fine powder, and sends it down the wooden feed- 

 pipes to the moulds : a jet of steam, however, 

 meets it on its way down, so as slightly to moisten 

 it before it reaches the moulds, which are of iron, 

 and of the same size laterally as the bricks, but 

 are much deeper vertically, so as to receive 

 enough of the powdered clay to form a brick when 

 the moulds are filled. Plungers of iron come 

 down and press the powder into a compact hard 

 brick, ready to be conveyed immediately to the kiln 

 for burning. The various contrivances connected 

 with this machinery are simple, but ingenious : 

 each operation of the plungers forms two bricks, 

 the moulds being in pairs ; and although, from the 

 length of the drying-cylinders (60 feet each), the 

 machine occupies great space, yet the process is 

 so regular, that, with a proper supply of clay, the 

 moulding of the bricks at the end is very rapid 

 and regular. The bricks made by the machine 

 are truer, harder, and heavier than those made by 

 hand. There is reason to believe that they will 

 also prove more durable. 



Tiles are prepared much in the same way as 

 bricks ; only, from their being thinner, and of 

 a more intricate form, they require to be made 

 of finer and tougher materials, and are always 

 burned in kilns. They are of different kinds, 

 according to the use to which they are applied 

 as plain and pan tiles, ridge tiles, &c. In fig. 2, 

 d shews the form of the mould for a ' pan-tile.' 



Drain tiles and tubes are always made by 

 machine : the former are of a horse-shoe shape, 

 and are made by rolling out the clay into sheets 

 between two cylinders, and thereafter cutting out 

 the necessary oblong parts, and bending them 

 into the proper shape by an ingenious assemblage 

 of endless chains, levers, pulleys, &c. The tubes 

 are made by pressing clay 

 from a cylinder through 

 dies of the size and shape 

 of the tube wanted, the 

 cutting off of the lengths 

 being also effected by 

 the machine. Hollow 

 bricks, now so much used, 

 are also made by machin- 

 ery. In fig. 3 we give 

 diagrams of the dies used 

 for forming various hollow articles : a is the die 



Fig- 3- 



for the hollow brick shewn in perspective at e , a 

 die for a circular drain-tube ; c, a die for a drain- 

 tube with flat bottom; and d, a die for a form 

 of hollow earthenware brick used for fire-proof 

 staircases. In all these, the clay is forced through 

 the spaces represented white; the shaded parts 

 being the iron portion of the dies. A very great 

 variety of machines have been introduced for this 

 branch of the earthenware manufacture. 



For architectural decorations, figures, vases, &c, 

 on a large scale, known by the name of terra-cotta 

 literally, baked clay various kinds of clay are 

 used, but in this country those chiefly from the 

 coal-measures. These are worked into a homo- 

 geneous paste, which is modelled or cast into the 

 figure required, then slowly dried in the air, and 

 ultimately fired to a proper hardness in a proper 

 kiln. Tobacco-pipes are made of a finely ground 

 white plastic clay, called pipe-clay, chiefly found 

 near Wareham in Dorsetshire. This clay being 

 worked into paste and dough, in the same man- 

 ner as the finer sorts of potters' stuff, is next 

 rolled into cylinders for the stems, and into balls 

 for the bowls. These are then pressed to the 

 desired form in metallic moulds, and pierced with 

 a wire ; dried for a day or two, scraped, polished, 

 and dipped ; and ultimately fired in a baking-kiln 

 for ten or twelve hours. A clever workman, aided 

 by a boy, can easily make from five to six gross 

 of plain pipes per day. For Meerschaum, see 

 USEFUL MINERALS. 



Pottery, 



or the art of making vessels for use out of 

 ordinary clay, was probably the earliest effort at 

 artistic manufacture made by man. From plaster- 

 ing clay on his rude hut, he would learn much of 

 its qualities, and could hardly fail to see that it 

 could be of use to him if moulded into forms 

 which would hold water, or in which he could 

 cook his food. At first, there is no doubt such 

 rude vessels were simply moulded by hand, and 

 sun-dried ; but in time, the perishability of these 

 vessels would lead to their being fire-burned in- 

 stead, and durability would be thus attained. 

 But as great a revolution would be accomplished 

 when the difficulty of turning so soft a material 

 round at the same time the hand was fashioning 

 it into shape, led to the adoption of a disk of 

 wood on a pivot, probably at first placed in a 

 hole in the ground, and so introduced the idea of 

 the potter's throwing-wheel, the most simple, and, 

 for the purpose, the most effective machine in use. 

 It is now placed on a bench, for greater con- 

 venience, and turned by a wheel and band, as in 

 fig. 5 ; but in other respects it has hardly been 

 altered since its original invention. 



The next great stage in the manufacture of 

 pottery was the discovery of the art of applying 

 a vitreous glaze over its surface, and thus render- 

 ing it more impervious to moisture, and also more 

 beautiful. This is of great antiquity, and so is 

 the art of enamelling pottery : the latter was 

 extensively practised by the ancient Egyptians 

 and Assyrians ; whilst the former is constantly 

 met with in the remains of the earliest and best 

 periods of Greek and Roman pottery. Some of the 

 enamels and glazes used by the ancients are of so 

 fine a quality that they are even now unsurpassed. 

 For a long time, during the decline and fall of 



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