Either a conquered enemy or the chief of a wild tribe (in conspiracy with the conqueror) may inform the besieged: "With the intention of escaping from a disease, or from the attack in his weak point by his enemy in the rear, or from a rebellion in his army, the conqueror seems to be thinking of going elsewhere, abandoning the siege." When the enemy is made to believe this, the conqueror may set fire to his camp and retire. Then the enemy coming out may be hemmed . . . as before.