Mobile Bay lies like a great bell open to the south--a bell that is thirty miles long, fifteen wide at the mouth, and six at the head. It is a shoal-water bay, save for a rather deep hole (twenty-one feet) just within; the two sandy islands that stretch out from either side across its mouth almost meet. That is to say, they reach within 2,000 yards of each other, and between them lies the entrance to the channel. In these days a wide ditch carries twenty-three feet of water from the deep hole inside the islands clear to the town of Mobile; but at the time of the Civil War that had not been dredged, and the water shelved gradually from the ripples at the beach to twelve feet at the centre line above the hole. There was a bar outside; but ships drawing twenty feet of water could pass. The main point of land at the entrance to Mobile Bay lay on the east, and was called Mobile Point. On the west lay Dauphin Island, and the water between this island and the mainland was and is called Mississippi Sound--a stretch of shoal water that gives inland navigation to New Orleans. The Confederate defences, ashore and afloat in 1864, are described by Mahan as follows: “The entrance from the Gulf was guarded by two works, Fort Morgan on Mobile Point, and Fort Gaines on Dauphin Island. The approach by Mississippi Sound was covered by Fort Powell, a small earthwork on Tower Island, commanding the channel which gave the most water, known as Grant’s Pass. Gaines was too far distant from the main ship channel to count for much in the plans of the fleet. It was a pentagonal work mounting in barbette three X-inch columbiads, five 32-, two 24-, and two 18-pounder smooth-bore guns, and four rifled 32-pounders; besides these it had eleven 24-pounder howitzers for siege and for flank defence. In Fort Powell there were one X-inch, two VIII-inch and one 32-pounder smooth-bore and two VII-inch Brooke rifles; these bore on the sound and channels, but the rear of the fort toward the bay was yet unfinished and nearly unarmed. The third and principal work, Fort Morgan, was much more formidable. It was five-sided, and built to carry guns both in barbette and casemates; but when seized by the Confederates the embrasures of the curtains facing the channel were masked and a heavy exterior water battery was thrown up before the northwest curtain. The armament at this time cannot be given with absolute certainty. The official reports of the United States engineer and ordnance officers, made after the surrender, differ materially, but from a comparison between them and other statements the following estimate has been made: Main fort, seven X-inch, three VIII-inch and twenty-two 32-pounder smooth-bore guns, and two VIII-inch, two 6.5-inch and four 5.82-inch rifles. In the water battery there were four X-inch and one VIII-inch columbiads and two 6.5-inch rifles. Of the above, ten X-inch, three VIII-inch, sixteen 32-pounders and all the rifles, except