the army could
not retire into some city, it was compelled to live in the camp, which
was arranged and fortified according to a uniform plan, so that every
company and individual had a place assigned. We cannot tell when this
practice of intrenchment began; it was matured gradually, like all other
things pertaining to all arts. The system was probably brought to
perfection during the wars with Hannibal. Skill in the choice of ground,
giving facilities for attack and defence, and for procuring water and
other necessities, was of great account with the generals. An area of
about five thousand square feet was allowed for a company of infantry,
and ten thousand feet for a troop of thirty dragoons. The form of a camp
was an exact square, the length of each side being two thousand and
seventeen feet; there was a space of two hundred feet between the
ramparts and the tents to facilitate the marching in and out of
soldiers, and to guard the cattle and booty; the principal street was
one hundred feet wide, and was called Principia. The defences of the
camp consisted of a ditch, the earth from which was thrown inward, and
of strong palisades of wooden stakes driven into the top of the
earthwork so formed; the ditch was sometimes fifteen feet deep, and the
_vallum_, or rampart, ten feet in height. When the army encamped for the
first time the tribunes administered an oath to each individual,
including slaves, to the effect that they would steal nothing out of the
camp. Every morning at daybreak the centurions and the equites presented
themselves before the tents of the tribunes, and the tribunes in like
manner presented themselves before the praetorian, to learn the orders
of the consuls, which through the centurions were communicated to the
soldiers. Four companies took charge of the principal street, to see
that it was properly cleaned and watered; one company took charge of the
tent of the tribune; a strong guard attended to the horses, and another
of fifty men stood beside the tent of the general, that he might be
protected from open danger and secret treachery. The _velites_ mounted
guard the whole night and day along the whole extent of the vallum, and
each gate was guarded by ten men; the _equites_ were intrusted with the
duty of acting as sentinels during the night, and most ingenious
measures were adopted to secure their watchfulness and fidelity. The
watchword for the night was given by the commander-in-chief. "On the
fi