Could Demosthenes succeed in storming this outwork, and in reëstablishing the Athenian troops on the high ground, he might fairly hope to be able to resume the circumvallation of the city and become the conqueror of Syracuse; for when once the besiegers' lines were completed, the number of the troops with which Gylippus had garrisoned the place would only tend to exhaust the stores of provisions and accelerate its downfall.

On reconnoitring the situation of the city, finding that the enemy were panic-stricken, because the cavalry in which they placed their chief reliance were beaten, he encouraged his men to endure the toil, and began to draw a line of circumvallation round Alesia.

When the enemy perceived this, their boldness increased, as usually happens, from the fears of others; and, having attacked his camp by night, when open force availed little, they drew lines of circumvallation around it on the following day.

The circumvallation in its best preserved places is now from seven to ten feet high.