The silence of our guns in the presence of an assailing foe, disheartened our men for an instant, but they immediately betook themselves energetically to their task on the defences, though the enemy's shells exploded in every direction about them. On the 4th the Mexicans again resumed the fight and continued their vollies until midnight. At nine o'clock on that evening irregular discharges of musketry were heard in our rear apparently extending a mile up the river, and continuing until near the termination of the cannonade. Every soldier in the fort therefore stood to his arms all night long, manning each battery and point of defence in expectation of an assault from the forces that had crossed the river and filled the adjacent plains and thickets. But the anxious night passed without an attack at close quarters, and, at day-light, on the 5th, the enemy again commenced their fire from the distant batteries. The sound of war was gratifying to the Mexicans, but its conflicts were safer from behind the walls and parapets of their forts, with an intervening river, than in dangerous charges against the muzzles of our guns! As soon as the cannonade recommenced, it was immediately returned by a few discharges from the eighteen-pounders and six-pounder-howitzer; and the voice of our guns once more exhilarated the men, though their shots were ineffectual. Both batteries ceased firing simultaneously, and our indefatigable soldiers again set to work on the defences, completed the ramparts, and made rapid progress in the construction of a bomb-proof and traverse in rear of the postern. These were anxious days and hours for a garrison short of ammunition, assailed by an enemy equipped with every species of deadly missile, probably surrounded by superior numbers concealed on the left bank of the river, and yet forced to labor on the very fortifications which were to keep off the foe. During all this time, however, no one desponded. Day and night they toiled incessantly on the works amid the shower of shot and bombs, nor was a sound of sorrow heard within the little fort until its brave commander fell, mortally wounded by a shell, on the 6th of May. The game was kept up during all this day; mounted men were seen along the prairie, while infantry were noticed creeping through the thickets; but a few rounds of canister, from Bragg's battery, dispersed the assailants. About four o'clock of this day a white flag was observed at some old buildings in the rear of our work, and a parley was sounded by the enemy. Two officers were soon descried approaching us, and an equal number were despatched by Captain Hawkins, (who had succeeded Major Brown in the command of the fort,) to meet them within two hundred and fifty yards of our lines. A communication from General Arista was delivered by the herald, and the Mexicans were requested to retire a short distance and await the reply.