cemented together, another row is added above, in such a
manner that the same interval may be observed, and that the beams may
not touch one another, but equal spaces intervening, each row of beams
is kept firmly in its place by a row of stones. In this manner the whole
wall is consolidated, until the regular height of the wall be completed.
This work, with respect to appearance and variety, is not unsightly,
owing to the alternate rows of beams and stones, which preserve their
order in right lines; and, besides, it possesses great advantages as
regards utility and the defence of cities; for the stone protects it
from fire, and the wood from the battering ram, since it [the wood]
being mortised in the inside with rows of beams, generally forty feet
each in length, can neither be broken through nor torn asunder.

XXIV.--The siege having been impeded by so many disadvantages, the
soldiers, although they were retarded during the whole time, by the mud,
cold, and constant showers, yet by their incessant labour overcame all
these obstacles, and in twenty-five days raised a mound three hundred
and thirty feet broad and eighty feet high. When it almost touched the
enemy's walls, and Caesar, according to his usual custom, kept watch at
the work, and encouraged the soldiers not to discontinue the work for a
moment: a little before the third watch they discovered that the mound
was sinking, since the enemy had set it on fire by a mine; and at the
same time a shout was raised along the entire wall, and a sally was made
from two gates on each side of the turrets. Some at a distance were
casting torches and dry wood from the wall on the mound, others were
pouring on it pitch, and other materials, by which the flame might be
excited, so that a plan could hardly be formed, as to where they should
first run to the defence, or to what part aid should be brought.
However, as two legions always kept guard before the camp by Caesar's
orders, and several of them were at stated times at the work, measures
were promptly taken, that some should oppose the sallying party, others
draw back the towers and make a cut in the rampart; and moreover, that
the whole army should hasten from the camp to extinguish the flames.

XXV.--When the battle was going on in every direction, the rest of the
night being now spent, and fresh hopes of victory always arose before
the enemy: the more so on this account because they saw the coverings of
our towers burnt