APPENDIX.

XIX for forming the foundations of the walls of theatres. The walls should then be built upon these foundations with squared blocks of considerable length, so that the stones between these blocks, which extend across the wall, may be bound firmly together. The space inclosed by the walls may be filled in with rubble, or stone-work, and be made so firm that a tower may be erected upon it. The mole being completed, (continues our author) the docks should be built facing the north ; because the greater heat of a southern aspect occasions a more rapid decay, and engenders and nourishes moths, ship-worms, and other noxious insects. Timber should, at the same time, be used as sparingly as possible in works of this kind, that they may not be liable to accidents by fire *.

Harbours f of this kind were usually built in a semicircular form, with arms of great length extended into the sea ; these were soraetimes called from their resemblance to crabs’ claws Cicero terms them cornua (horns). (Epist. ad Attic, lib. ix. ep. 19.)

For the better security of the ships within the harbour, it was usual to draw strong chains or booms across the entrance, and to defend them with large pales, fortified against the water with pitch.

On both sides of the mole were strong towers, which were garrisoned with troops ; and not far from these was a watch-tower, or lighthouse, called Pharos, which name belonged originally to a little island in the mouth of the Nile, where the first of these towers was built, but was afterwards naturalized both in Greece and at Rome.

In the innermost part of the harbour vessels were often sufiered to lie unmoored, whereas in other parts of the port, which were not so well secured, they were either chained to the land, or obliged to lie at anchor. This portion of the harbour was divided into several partitions by walls, constructed for the most part with stone, within * See Wilkins’s Vitruvius.

t The following remarks on the ports and vessels of the ancients are drawn from the Archaeologia of Potter ; and we have thought it not irrelevant to the subject to bring them together on the present occasion, t Diodorus, lib. xii.

c 2