HEADQUARTERS YAZOO EXPEDITION,
Five miles from Greenwood, March 15, 1863-9 p. m.

MY DEAR RAWLINS: We are no nearer Greenwood than when I wrote you night before last. We didn't attack yesterday, because the gunboats had not finished their repairs, and put it off to-day out of respect for the Sabbath; but to-morrow it is arranged to try it again, though I am not over-sanguine of success, since I can see a disposition on the part of the Navy to keep from a close and desperate engagement. I've talked with them all and tried to give them backbone, but they are not confident. Smith, you doubtless have understood by this time, I don't regard as the equal of Lord Nelson. Walker and Foster, of the De Kalb and Chillicothe, are good men, and will cheerfully do what they are ordered, but both think of Commodore Smith just as I do. I don't hesitate to say that, although the rebels got ahead of us in obstructing the Pass, and thereby kept us back ten days, and although we were furnished with miserable old transports and a new element of delay introduced, Commodore Smith is entirely responsible for the detention at this point and the consequent failure of the expedition, and responsible for no other reason than his timid and slow movements. When the iron- clads started into the Pass, I urged with all the force I could the absolute necessity of sending them, the rams, and two mosquitoes forward with all possible dispatch. Both Foster and Walker and General Ross agreed with this plan. Had this been done, they could have reached the mouth of the Tallahatchee in four days, I think, and even less. I'll bet my life I could have brought them to this point in three days; but grant that it would have required five days, that would have brought them to this place on the 1st of March, two whole weeks ago, at which time no heavy guns were here. The rifle did not arrive till about ten days ago. This we have from reliable authority.

I haven't time to tell you all the details of our operations here; but in the gunboat engagements they have suffered pretty heavily from the effects of the heavy rifle. At the distance of 1,100 yards the shots from this gun have battered and hammered the armored crafts sadly; they have not penetrated, but come so near that there is no fun in it. The Chillicothe is an inglorious failure; the wooden backing to her armor is of only 9-inch pine, and shivers into pieces every time the plating is struck; her bolt-work flies off at a terrible rate. If she is hit half as many times to-morrow at close range as she has been at long, she'll be in a sad condition. The De Kalb stands it well as long as she is square to the from, though her side do not fare so well. Add to all this, these gentlemen have ammunition for only two hours' fighting.

I have erected a battery on shore only 700 yards from the rebel fort, and have two 30-pounder Parrotts and one 8-inch ship gun in position to assist the Navy, but have only an average of 50 or 60 rounds for them. In addition to this, it is intended to embark one brigade on the lightdraught gunboats, and in case the rebel batteries are silenced, they will be landed at the fort to assault it and attack the rebel infantry if it should stand.

The latter part of the programme cannot be carried out unless the battery is completely disabled, so that we can run down and break up the raft that lies just above the fort.

The old steamship Star of the WEST is sunk just below the raft, across the stream, and they have the John Walsh close to the same place, either ready to sink or use as a boarding craft and ram. We have captured several prisoners, but can learn nothing of the rebel force,