most skilful investigations, and at once purchased an estate
near the sea in a healthy place, and asked the Senate and Roman people
for permission to remove the town. He constructed the walls and laid out
the house lots, granting one to each citizen for a mere trifle. This
done, he cut an opening from a lake into the sea, and thus made of the
lake a harbour for the town. The result is that now the people of Salpia
live on a healthy site and at a distance of only four miles from the old
town.

CHAPTER V

THE CITY WALLS

1. After insuring on these principles the healthfulness of the future
city, and selecting a neighbourhood that can supply plenty of food
stuffs to maintain the community, with good roads or else convenient
rivers or seaports affording easy means of transport to the city, the
next thing to do is to lay the foundations for the towers and walls. Dig
down to solid bottom, if it can be found, and lay them therein, going as
deep as the magnitude of the proposed work seems to require. They should
be much thicker than the part of the walls that will appear above
ground, and their structure should be as solid as it can possibly be
laid.

2. The towers must be projected beyond the line of wall, so that an
enemy wishing to approach the wall to carry it by assault may be exposed
to the fire of missiles on his open flank from the towers on his right
and left. Special pains should be taken that there be no easy avenue by
which to storm the wall. The roads should be encompassed at steep
points, and planned so as to approach the gates, not in a straight line,
but from the right to the left; for as a result of this, the right hand
side of the assailants, unprotected by their shields, will be next the
wall. Towns should be laid out not as an exact square nor with salient
angles, but in circular form, to give a view of the enemy from many
points. Defence is difficult where there are salient angles, because the
angle protects the enemy rather than the inhabitants.

3. The thickness of the wall should, in my opinion, be such that armed
men meeting on top of it may pass one another without interference. In
the thickness there should be set a very close succession of ties made
of charred olive wood, binding the two faces of the wall together like
pins, to give it lasting endurance. For that is a material which neither
decay, nor the weather, nor time can harm, but even though buried in the
earth or set in the wate