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.