HEADQUARTERS SIXTEENTH ARMY CORPS, Memphis, Tenn., April 10, 1863.

Brigadier General W. S. SMITH, La Grange, Tenn.:

The time for our projected cavalry movement is rapidly approaching. General Dodge, in connection with General Rosecrans, is about to move on Tuscumbia. After taking that place, Rosecrans' cavalry will move rapidly to break the Georgia Central Railroad, under cover of my infantry brigade at Tuscumbia, and the Marine Brigade, of Ellet, now on their way to report to Dodge.

As soon as this movement is inaugurated, and the attention of the enemy drawn to that part of our line, your three regiments of cavalry will strike out by the way of Pontotoc, breaking off right and left, cutting both roads, destroying the wires, burning provisions, and doing all the mischief they can, while one regiment ranges straight down to Selma or Meridian, breaking the east and WEST road thoroughly, and sweeping back by Alabama. Rosecrans' cavalry will return through North Alabama, and thus cut the road from Corinth a SECOND time.

My present advices from Rosecrans are that about Wednesday of next week it will be necessary for Dodge to move. I shall, therefore, expect your cavalry to be got into the best order possible, both by grooming and care and by rest and feed. Let no exertion be spared in this matter. I hope to have horses; if not, and there are supplies of horses in Grierson's regiment or Prince's, have them appraised and bought in for the United States, and turned over to the SECOND Iowa. Let no horses be sold or sent out of the command.

I shall send the Seventh Kansas on Sunday to Corinth. I have now 100 horses from them, and want 60 more. I have telegraphed for Grierson to return at once, and expect him before Wednesday. Let the horses be all carefully shod.

Final instructions as to the course, &c., will reach you in time.

As this, if accomplished, will be a great thing, I am specially desirous that nothing interfere with the proper execution so far as the meanill admit. The corresponding movements from this place and Germantown will be directed by myself.

Chalmers has only about 1,800 men and one battery; no infantry. They are at Panola and Coldwater, near Senatobia. I have requested Prentiss to throw a force in his rear from Helena. Hope he will do it.

Your obedient servant,
S. A. HURLBUT.

FLAG-SHIP AUTOCRAT, Off Cairo, April 10, 1863.

Honorable E. M. STANTON:

SIR: I have the honor to inform you that the ram Switzerland passed the Warrenton batteries on the night of the 30th [25th] of March, and joined Admiral Farragut below. She was thoroughly repaired and in good condition. The Lancaster was the poorest boat in the ram fleet, and was very rotten. I trust that it will not be regarded as a reckless adventure sending these boats past the Vicksburg batteries, when it is remembered that they were the best that I could command, and the great importance to the country if the passage was successfully made be considered. The force under Admiral Farragut, in my judgment, was very inadequate for the duty he had to perform, and I feel satisfied of my success in getting one boat through to his support. The Switzerland is now commanded by Lieutenant Colonel John A. Ellet, and I shall confidently