a name given by the French engineers to a kind of mortar, which they use in raising the foundations of masonry under water. It consists of twelve parts of pozzolana or Dutch tarrafs, fix of good sand, nine of unslaked lime, thirteen of stone splinters about the size of an egg, and three of tile-dust or cinders, or scales of iron out of a forge; this being well worked together, is left to stand for about 24 hours, or till it becomes so hard as not to be separated without a pick-axe.