in natural history, a soft, greyish, brown, dense, and heavy marle: when dry, it is of a greyish 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 rough 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 aqua fortis.

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