COALBROOKDALE BRICK, TILE, AND TERRA COTTA WORKS.
Under the management of Mr. John Fox the clay-works of the Coalbrookdale Company have become so expanded and improved, that they now form an important department of the Company’s undertakings, and are at the present juncture, no doubt, among the more profitable of their industries. Since sanitary science has so successfully called public attention to the importance of the use of good bricks impervious to damp, the productions from these excellent coal-measure clays have been more in demand. Clays, as commonly understood, mean earth of sufficient ductility to allow of being kneaded into some useful shape or form, and rank as raw materials. Some are soft, others are indurated, or hard and rocky; but all have in one sense been prepared by certain poundings, grindings, washings, and mixings, carried on by Nature on a larger scale than that on which they are now still further fitted for use. They differ in quality, in degree of fineness, and in colour, and show certain relationships by which it is clear that they are descended from sand, just as sands are descended from a hardy race of pebbles, which in turn bear close relationship to rocks, from which undoubtedly they have been derived. Surface clays used for making inferior bricks and tiles, whose earthy odour gives evidence of alumina, are generally derived from red sandstone rocks, ground down into mud by the machinery of waves or streams whilst our deeper coal-measures clunches, and clays were originally the sediment thrown by rivers at their embouchures into inland lakes or seas, and are usually much more free from lime, iron, grit, and other foreign substances and impurities.
When brought to the surface, these clays are hard as a rock. Formerly they were allowed to lie during the winter to weather, as it is called; and a statute now obsolete required, under a heavy penalty, that bricks should not be made unless the clay for making them had been turned over at intervals, three times at least before the first of March. But brickmakers, not having patience to wait for the action of the weather, have invented machinery to do the work, and the clay is taken direct from the pit to be crushed by iron rollers, and then conveyed by coarse canvas-screens to tanks to be moistened, and afterwards to the pug mill. This is an upright cylinder, with a revolving vertical shaft, fitted up with horizontal knives following each other at an angle so as to cut, amalgamate, and temper the material, and which also acts as a screw to deliver it.
Ornamental bricks of elaborate design for architectural purposes require more delicate manipulation, and the clays for these undergo a more careful preparation. Machines in some instances are used, which take the clay, temper, thoroughly amalgamate it, and convert it into the finished article, and at the brick-yards of the Coalbrookdale Company presses have been erected by which bricks may be stamped at once from the semi-dry clay.
This company, too, have been at great pains to turn their clays to account by copying the Italian and Lombard style of making bricks of various forms and colours; and the buildings erected with these bricks, and others, with white facings of the same material, of which the present Literary and Scientific Institute is an example, possess great architectural beauty. Still further examples of the æsthetic treatment of these admirable clays were made a short time ago by Monsieur Kremer, who modelled and prepared at the company’s Lightmoor clay works, in relief, and on a large scale, an historical subject, connected with Scottish history in the time of King James, as a facade for a house in London; also some noble groups, life size, of figures representing the four seasons, for a gentleman’s grounds and park near London. The reader may judge of the adaptability of these clays for such purposes by inspecting a group of a similar kind in front of the Institute.
We exhibited ourselves in 1851 specimens of these and other coal-measure clays, with articles manufactured from them on both sides the river, and we had the satisfaction of hearing from distinguished judges, familiar with their merits, such as presidents of foreign Academics of Science, speak of them as superior to any they had ever seen. [306]
