CHAP. IV. Of Sand.
THere are three sorts of Sand, that is to say, Pit-Sand, River-Sand, and Sea-Sand. Pit-Sand is of all the best, and is black, white, red, or cindry, which is a sort of earth burnt by fire inclosed in the Mountains, and digged up in Tuscany. There is also digged in Terra di Lavoro, in the Territories of Baia and Cuma, a Sand called by Vitruvius, Pozzolana, which suddenly knits together in water, and makes building very strong; it hath been found by long experience, that of all Pit-Sand, the white is the worse: And of River-Sand, that from the stream which is found in the falls of water is the best, because it is more purged. The Sea-Sand is worst of all, and black∣ens and shines like glass, but that is better which is nearest the shore, and bigger. The Pit-Sand, because 'tis sat and tough (but apt to cleave) is therefore used in Walls and long Vaults. The River-Sand is very good for the covering, or rough-casting of Walls. Sea-Sand, because 'tis soon wet and soon dry, and moulders away by reason of the Salt, therefore is unfit to bear weight. All Sand is best in its kind, if being squeezed and handled, it crackles; and if being put upon a white cloth, it neither stains nor leaves it foul: that is bad, which mingled with