CLAY

consists of hydrated silicate of aluminium, with small proportions of the silicates of iron, calcium, magnesium, pota ium, and sodium. Of the chief kinds of clay porcelai/nrclay is the purest and besides that there is potter's clay, pipe-clay, and; fire-clay. Loam is day mixed with sand. The best wheats in Britain and the European Continent are grown on calcareous clay, as also are the finest fruits and flowers. No soil is really fertile without it