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 sorae- 
^ times 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 garri- 
soned with troops ; and not far from these was a watch-tower, or light- 
house, 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 
