in Natural History, a species of clay, of a grayish ash-coloured brown, in all degrees from very pale to almost black, and it has generally something of a greenish cast. It is very hard and firm, of a compact texture, of a tough and somewhat dusty surface that adheres slightly to the tongue. It is very soft to the touch, not staining the hands, nor breaking easily between the fingers. It has a little harshness between the teeth, and melts freely in the mouth. Thrown into water, it makes no ebullition or hissing; but swells gradually in bulk, and falls into a fine soft powder. It makes no effervescence with aquafortis.

The greatest quantity and the finest earth of this kind in the world, is dug in the pits at Wavendon, near Woburn in Bedfordshire. The strata in these pits lie thus: From the surface to the depth of fix feet, there are several layers or beds of sand, all reddish, but some lighter coloured than others. Under these there is a thin stratum of a sand-flone, which they break through, and then there is the fuller's earth. The upper stratum of this is about a foot thick: the workmen call it cledge, and throw it aside as useless; being commonly fouled with the sand which originally covered it, and which infinuates itself a good way into it. After this, they come to the fine fuller's earth for sale, which lies to the depth of eight feet more. The matter of this is divided into several layers, there being commonly about a foot and a half between one horizontal fissure and another. Of these several layers, the upper half, where the earth breaks itself, is tinged red; which seems to be owing to the running of the water upon it from among the sands above; some of which are probably of a ferruginous nature, or have ferruginous matter among them. This reddish fuller's earth the workmen call crop; and between the cledge and this there is a thin stratum of matter, of less than an inch, which in taste, colour, and external appearance, resembles the terra Japonica of the shops. The lower half of the strata of fuller's earth they call wall-earth. This is untinged with the red colour of the other, and seems the most proper for fulling. Under the fuller's earth there is a stratum of white and coarse stone about two feet thick. They seldom dig through this; but if they do, they find more strata of sand.

This earth is of great use in scouring cloths, stuffs, &c. imbibing all the grease and oil used in preparing, dressing, dressing, &c. of the wool; for which reason it is made a contraband commodity, and is not to be exported under the penalty of 1s. for every pound weight. See FULLING.

FULLER'S Weed, or Teazle. See DIPSAUCUS, BOTANY Index.