In 1724 Robert Redrich and Thomas Jones had a patent granted them for “a new art or method, as well for staining, veining, spotting, clouding, damasking, or otherwise imitating the various kinds of marble, porphyry, and other rich stones, and tortoiseshell, on wood, stone, and earthenware, and all and every such goods, wares, utensils, and things as are made, cut, or fashioned thereout, as for the making, marbling, veining, spotting, staining, clouding, and damasking any linen, silks, canvas, paper, and leather.” In 1726, and again in 1732, patents were taken out for methods of grinding flints, &c., which were of much importance. The first of these, by Thomas Benson, is described as “an engine or new method for the more expeditious working the said flint stone, whereby all the said hazards and inconveniences attending the same will effectually be prevented.” It is stated that in the making of “white pots,” flint stone is “the chief ingredient,” and that the method hitherto used in preparing it “has been by pounding or breaking it dry, and afterwards sifting it through fine lawns, which has proved very destructive to mankind;” and this invention is to obviate it, and is as follows:--The flint stones are first wetted, then crushed as fine as sand by two large wheels, of the bigness and shape of mill-stones, of iron, and made to turn upon the edges by the power of a water-wheel. This material is afterwards conveyed into large circular iron pans, “in which there are large iron balls, which, by the power of the water-wheel above named, are swiftly driven round: in a short time the operation is concluded, and by turning a tap the material empties itself into casks.” The next one, by the same Thomas Benson, taken out in 1732, was described as--