midnight
`` Fifty miles to the south of us , on the other side of the Tagus , is the army of General Clausel . His camp is situated near a peak named the Sierra d'Ossa . On the summit of this peak is a beacon , and by this beacon he has a picket . It is agreed between us that when at midnight he shall see our signal-fire he shall light his own as an answer , and shall then at once fall back upon the main army . If he does not start at once I must go without him . For two days I have endeavoured to send him his message . It must reach him to-day , or his army will be left behind and destroyed . ''