On Thursday, the 11th of April, a boat was seen approaching the work, with Colonel Chesnut, Colonel Chisholm and Captain Lee, aids to General Beauregard. They handed Major Anderson a communication from General Beauregard, which was a summons to evacuate the fort. It was to this effect: that the Confederate authorities had refrained from any hostile act against Fort Sumter in anticipation that the government of the United States would withdraw its troops from that fort; that it appeared probable at one time that this would have been done, but that the authorities of the Confederate States could no longer refrain from taking possession of a fort that commanded the entrance to one of their principal harbors, and that the order to evacuate the fort was now made upon the following terms: The troops to be allowed to carry with them their arms, all personal baggage and company property of every description, and the flag which had been maintained with so much fortitude, might be saluted when hauled down. Major Anderson replied, that his word of honor, and the duty he owed to his government, forbade his compliance with the demand. These gentlemen then left the fort, displaying a _red_ flag. At half-past 1 A. M., on Friday, a boat containing Colonel Chesnut, Captain Lee and Colonel Roger A. Pryor, approached the work with a communication from General Beauregard, making inquiry as to what day Major Anderson would evacuate the work, and asking if he would agree not to open his batteries unless Fort Sumter was fired upon. Suspecting from the urgency of this midnight negotiation, some strong necessity on the part of his opponent, but convinced that an evacuation would be inevitable, Major Anderson made a written reply, stating that he would evacuate the fort at noon, on the 15th, provided he did not receive supplies or controlling instructions from his government to the contrary. That he would not open his batteries unless the flag of his country was fired upon, or unless some hostile intention on the part of the Confederate forces should be manifested. Being in hourly expectation of the arrival of a United States fleet with reinforcements off the harbor, and urged to instant action by dispatches from Montgomery, General Beauregard had prepared his messengers for this answer. Anderson’s communication was handed to Colonel Chesnut shortly after 3 o’clock, who, after a short consultation with the officers who had accompanied him, handed a communication to Major Anderson, and said, “General Beauregard will open his batteries in one hour from this time, sir.” Major Anderson looked at his watch, and said, “It is half-past three. I understand you, sir, then, that your batteries will open in an hour from this time?” Colonel Chesnut replied, “Yes, sir, in one hour.” They then retired. FORTIFICATIONS IN CHARLESTON HARBOR.