Pliny: Natural History, Vol. V

narrower mouth, but with the shaft expanding in the interior, as is the practice in mines. This is used chiefly in Britain. Its effect lasts for 80 years, and there is no recorded case of anyone having scattered it on the same land twice in their lifetime. A third kind of white marl is called glisomarga a mixture of fuller’s chalk and greasy earth; it is a more effective dressing for pasture than for corn, so that when a corn crop has been harvested, a very abundant crop of hay can be cut before the next sowing; however, while the corn is growing, the land does not produce any other plant. Its effect lasts 30 years; but if it is scattered too thickly, it chokes the soil just as Signinum a Roman plaster made of crushed pottery and lime does. For dove-coloured marl, the provinces of Gaul have a name in their own language, eglecopala a Celtic term for dove-coloured marl; it is extracted in blocks like stone and is split by the action of sun and frost so as to form extremely thin plates. This kind of marl is equally fertile. Farmers use sandy marl if no other is available, but they use it on damp soils even if another sort is available. The Ubii are the only race known to us who, while cultivating extremely fertile land, enrich it by digging up any earth from below three feet and spreading it on the land in a layer a foot thick; but the benefit of this top-dressing does not last longer than ten years. The Aedui and the Pictones have made their arable land extremely fertile by means of chalk, which is indeed also found to be most useful for olives and vines. But all marl should be thrown on the land after it has been ploughed, in order that its medicinal properties may be absorbed; and it requires a moderate amount of dung, as at first it is too rough and does not diffuse into the vegetation; otherwise, whatever

sort of soil it is, it will be harmed by the novelty, as it does not promote fertility even in the first year. It also makes a difference what sort of soil the marl is required for; the dry kind is better for a damp soil and the greasy kind for a dry soil, while either sort—chalk-marl or dove-marl—suits land of medium quality.