As the reader will remember, a chart of the mouth of the Mississippi is marvellously like a picture of the roots of a crooked tree. The waters divide into three main channels, with a host of offshoots. To effectually close all the entrances to the river it was necessary only to anchor the squadron in the river itself above the point where it was split up, and this was done. There were no Confederate forts near the anchorage, and the officers and men, so far as is known, possessed their souls in peace until the month of October. Meantime the Confederates had been working against very great difficulties to prepare a squadron fit to clear the river. They had incidentally striven to get a steamer called the _McRae_ in commission for a cruiser, but had failed in making her machinery work well, and she was relegated to the work of harbor defence. [Illustration: Passes of the Mississippi. _From “The Navy in the Civil War.”_] The work of shipbuilding was done under the eyes of a commission that included Capt. L. Rousseau, Commander E. Farrand, and Lieut. Robert J. Chapman, of the Confederate navy, all of whom had been reared in the government navy. Capt. George N. Hollins, formerly of the American navy, was assigned to command the fleet when built. By the first of October, four river steamers had been converted into the semblance of gunboats by adding timbers so that they could carry eight or nine guns. They were called the _Polk_, the _Ivy_, the _Livingston_, and the _Maurepas_. A merchant steamer with a bark rig became the _McRae_. To this was added a most remarkable vessel--the first of her class, the ironclad ram _Manassas_. The _Manassas_ was originally the double-screw tug _Enoch Train_, of Boston. She was 128 feet long, twenty-six wide, and when loaded she drew thirteen feet of water. She was, in short, a tug of the first class in size. Capt. John A. Stevenson, of New Orleans, undertook the contract of making a ram of this vessel for a company of capitalists who determined to use her, privateer-fashion, against the government blockaders immediately after the Confederate Congress enacted a law on May 21, 1861, binding the Confederate treasury to pay to the destroyers twenty per cent. of the value of any government ships that might be destroyed by volunteers. The tug was cut down almost to the water, first of all, and then her bow was filled in solid with timbers for a space of twenty feet abaft the stem. A deck in the shape of half of a long, sharp egg was built over her, twelve-inch oak timbers being used for the purpose. Of course, all the woodwork was thoroughly bolted. Then the bow and the rounded deck were everywhere plated with flat bar-iron one and a half inches thick. There was one gun-port forward, where a sixty-eight-pounder was mounted, but for some fault of construction they were not able to use it at first.