Numbers 2. Reports of Captain Miles D. McAlester, Corps of Engineers, U. S. Army, Chief Engineer.

OFFICE OF CHIEF ENGINEER, MILITARY DIVISION OF WEST MISSISSIPPI,

New Orleans, August 17, 1864.

GENERAL: Presuming that accounts of any tests applied to the efficiency of our sea-coast fortifications to fulfill their objects interest you, I will give you a brief one of the passage of Fort Morgan by Admiral Farragut on the 5th instant.

The armament of the fort, according to our best information, consists of 10-inch columbiads and 7-inch Brooke rifles bearing upon the water; some of the land guns are probably lighter. There appears to be a good provision of traverses on the terre-plein. The rebels have added a battery of ten or twelve guns of the above- named calibers, outside the fort proper, placing it upon the beach in front of the curtain, which bears directly across the channel (nearly west). Another battery of nearly the same strength they have placed on the beach farther to (enfilades) the channel after it changes its course to nearly northwest. The inference can be fairly drawn that on these, the two strongest water fronts, and the only ones originally designed to mount guns in casemate, the casemates have been closed or masked, since the embrasures were not high enough to clear the guns mounted on the beach in front, as above described. The information we have corroborates this inference. I regret that I cannot state the precise number and caliber of guns bearing upon the different portions of the channel. The number on the two principal water fronts is probably about thirty each of the above-named calibers, and on the front, looking on the channel approach, about fifteen, all 7-inch rifles.

The entire fleet off Mobile consisted of four monitors and twenty- six wooden ships. Of these all but twelve wooden ships started for the bay; these twelve were left for the purposes of blockade and external co-operation. My sketch herewith will give you very clearly the admiral's dispositions for the passage, which were ingenious and strategic. The object in lashing by twos was to diminish the chances of sinking or abandonment-one of a couple being struck, for example, so as to sink her, the other would float her up, or if her machinery were disabled, her consort would take here through. The intervals were determined (for the wooden ships) by the consideration that as one couple turned at B (see sketch) upon the new course, so as to be exposed to the raking fire of the fort, the next succeeding couple would be throwing its broadsides of grape and canister into the raking batteries. In lashing a side- wheel with a screw accidents from the fouling of the latter by ropes, nets, &c., were avoided, since the side-wheel, not easily fouled, could carry its consort through. The total broadside of the passing fleet available against the fort was about seventy-five guns. The monitors could use their guns during the approach. The Brooklyn had four bow guns, and the other wooden ships one or two bow guns each, giving a total fire of about thirty guns available against the fort from the fleet during its approach. The night and morning were all that could be expected or hoped for. A tolerably stiff breeze from the WEST blew directly into the face of the fort. Many a hear on our side sent up a prayer of thanksgiving for that breeze, a and doubtless many