attack is made by land and sea. Still it may be doubted whether the enemy can immediately spare the number of troops from his armies in the North and West for the attack here, and as the possession of this city would give him moral rather than military advantages in the prosecution of the war, it may well be relieved that our greatest danger lies in a naval attack by his iron-clad fleet, so soon as it can be prepared for service. The means of defense which we have against such an attack are well known to the commanding general. Our fortifications, strengthened and increased as they have been, are formidable, and may suffice against an attack of wooden vessels. Against iron-clad vessels, however, the case is different. If they succeed in making a rendezvous inside the bar it is probable that they can at once run past the forts and open fire on the city. The means which first occur for preventing their passage, obstructing the passage between Forts Sumter and Moultrie, have been tried, and I regret to say that up to this time have not succeeded. Something of the same kind was tried when I was in command and held for a while in the position where parts of the lately constructed boom are now lying, but the same obstacles were encountered in making the obstructions permanent. I had determined to give up the lower position and obstruct the upper channels between the shoals, nearer the city, where the force of the tide is much less and where the holding ground is good and secure. That we may have the benefit of obstructions to some extent I would recommend that when those having the matter in charge are satisfied that the lower boom is impracticable the material may be used for blocking the harbor in the channels between Fort Johnson and the Middle Ground, between Middle Ground and Crab Bank and Hog Island Channel, near Sullivan's Island. This would delay the enemy under fire of the outer forts and be of some utility. I fear that laying it in sections or placing it in any way between Sumter and Moultrie will be absolutely useless.

Preparations for explosive obstructions in the channels, I understand, are in progress, but I have not learned of their having been so far advanced as to assist in the defense of the harbor. The main defense at the command of the military authorities, therefore, consists in the forts and batteries around the harbor.

Requisitions have been made by the commanding general for an additional supply of heavy ordnance, comprising some fifty heavy guns, with their proper ammunition. I believe the requisitions have been approved at Richmond, and that they will be supplied so far as the means at the command of the Government will admit. These, however, are limited and transportation slow. I do not think it of any use to make requisition for material until those requisitions are filled. It will of course be advisable to strengthen even then; for delay, if accorded us, will of course strengthen the enemy also.

I will briefly notice the works for the defense of the harbor and state what additional force is, in my opinion, necessary, and what disposition of means at hand and already acquired would be advisable.

Morris Island: The work extending across the island at a distance of about 2,400 yards from Fort Sumter protects the island to the southward, and will while held effectually prevent the erection of batteries against that castle. It has five guns mounted and two others waiting for carriages. The garrison consists of two companies of artillery and Colonel R. F. Graham's regiment of infantry. The position, in my opinion, requires an addition of two or more long-range guns to enable the garrison to reach transports lying inside the bar. It also requires a light battery of four pieces. The garrison, with the addition of one company