HDQRS. DEPT. OF Mississippi AND EASTERN LOUISIANA, Jackson, March 14, 1863.

General JOSEPH E. Johnston,
Commanding Chattanooga:

GENERAL: Your letter of the 11th instant, from Mobile, has just one of which [the lower] completely enfilades it. The range, however, is long, 1 7/8 miles, but effective. The battery consists of one 10-inch columbiad, one 10-inch mortar, and a 30-pounder Parrott. The upper battery, range 1 3/4 miles, consists of one 10-inch columbiad and one Whitworth; a 7-inch Blakely also bears on mouth of canal, but at still longer range.

I am now fortifying Grand Gulf and mounting two 8-inch naval guns, a banded 32-pounder rifled, and two 32s, rifled but not banded. The three first-named guns belong to the Navy Department, and were intended for boat building at Shreveport, La., as transportation by land to Port Hudson for these guns was impossible from the condition of the roads, and, as navigation by Mississippi River was uncertain and dangerous, I took temporary possession of them, notifying the Department of the fact. The Secretary of War, though blaming my action as unauthorized, has allowed their retention, and will endeavor to supply the navy with others. I think it hardly necessary to say that the apparent probability of success with the canal made it necessary to establish another battery below, and that the mouth of Big Black, from its relation to Vicksburg, induced the selection of Grand Gulf. Ellis' Cliff, 18 miles below Natchez, per se, has superior advantages for locating a battery, but has no connection with Vicksburg. The dredge-boats [two] have advanced only one-FIFTH the length of the canal. Spade works is stopped for the present. I begin to hope it may prove a failure.

The high water has driven within the last few days a large part of the transport fleet, with many troops, higher up the river, but to what point has not yet been reported. River falling slowly. General Gardner, at Port Hudson, estimates Banks' forces at Baton Rouge at least 30,000. Farragut, with Essex, Richmond, Hartford, Monongahela, Pensacola, and Tennessee, and a large number of mortar-boats, below. Banks made a forward movement with a part of his army on the 11th by three roads, but has not advanced since.

I have telegraphed you to-day and yesterday as to operations on Tallahatchee. Some eight or nine gunboats, two of them iron-clad, and about seventeen or twenty transports, after cutting through nearly a mile of solid Tallahatchee, on the 11th with iron-clads, and were repulsed; one boat considerably damaged. On yesterday they renewed the attack with great vigor, and continued it until after sunset, from ten to sixteen heavy boat guns, and from a mortar and two guns on land. We lost several men, and a 11-inch shell passed through 16 feet earth and a bale of cotton, blowing up the magazine of one Whitworth gun; this the only damage.

General Loring, in command, telegraphs cartridges were being prepared for the gun, and notified me of arrival of ammunition for heavy guns. He says loss of the enemy must have been very great. Our shot struck constantly, scattering burning cotton. I think Colonel - can hold the place. It is located on a narrow neck 6 miles above Greenwood.

A raft and steamboats sunk obstruct the river opposite the fort.