WAR DEPARTMENT, January 16, 1861.

Maj. ROBERT ANDERSON,
          First Artillery, Commanding Fort Sumter:

SIR: Your dispatch No. 17, covering your correspondence with the governor of South Carolina, has been received from the hand of Lieutenant Talbot. You rightly designate the firing into the Star of the West as "an act of war," and one which was actually committed without the slightest provocation. Had their act been perpetrated by a foreign nation, it would have been your imperative duty to have resented it with the whole force of your batteries. As, however, it was the work of the government of South Carolina, which is a member of this confederacy, and was prompted by the passions of a highly-inflamed population of citizens of the United States, your forbearance to return the fire is fully approved by the President. Unfortunately, the Government had not been able to make known to you that the Star of the West had sailed from New York for your relief, and hence, when she made her appearance in the harbor of Charleston, you did not feel the force of the obligation to protect her approach as you would naturally have done had this information reached you.

Your late dispatches, as well as the very intelligent statement of Lieutenant Talbot, have relieved the Government of the apprehensions previously entertained for your safety. In consequence, it is not its purpose at present to re-enforce you. The attempt to do so would, no doubt, be attended by a collision of arms and the effusion of blood--a national calamity which the President is most anxious, if possible, to avoid. You will, therefore, report frequently your condition, and the character and activity of the preparations, if any, which may be being made for an attack upon the fort, or for obstructing the Government in any endeavors it may make to strengthen your command.

Should your dispatches be of a nature too important to be intrusted to the mails, you will convey them by special messengers. Whenever, in your judgment, additional supplies or re-enforcements are necessary for your safety, or for a successful defense of the fort, you will at once communicate the fact to this Department, and a prompt and vigorous effort will be made to forward them.

Very respectfully, your obedient servant,

J. Holt