32. 鳥集者虛也夜呼者恐也
If birds gather on any spot, it is unoccupied.
A useful fact to bear in mind when, for instance, as Ch‘ên Hao says, the enemy has secretly abandoned his camp.
Clamour by night betokens nervousness.
Owing to false alarms; or, as Tu Mu explains it: 恐懼不安故夜呼以自壯也 “Fear makes men restless; so they fall to shouting at night in order to keep up their courage.” The T‘ung Tien inserts 喧 before 呼.
33. 軍擾者將不重也旌旗動者亂也吏怒者倦也
If there is disturbance in the camp, the general’s authority is weak. If the banners and flags are shifted about, sedition is afoot.
The T‘ung Tien and Yü Lan omit 旌.
If the officers are angry, it means that the men are weary.
And therefore, as Capt. Calthrop says, slow to obey. Tu Yu understands the sentence differently: “If all the officers of an army are angry with their general, it means that they are broken with fatigue” [owing to the exertions which he has demanded from them].