Major-General Ulysses S. Grant to Acting Rear Admiral David D. Porter, June 21, 1863

Head Quarters Dept of the Tennessee        

Near Vicksburg June 21st 1863

Admiral D. D. Porter Comdg Miss Squadron.

Admiral:—

Information received from Vicksburg last night confirms your theory of the probable method Pemberton will take for escaping in the last extremity. One of our Pickets and one of the enemy by mutual consent laid down their arms, met half way and had a long conversation. The rebel said that our cannonading killed and wounded a great many in the rifle pits, otherwise done no great damage. They fully counted upon an assault as being intended and were prepared for it. Finding that no assault was made, the feelings of the troops was canvassed to see if they could be got out to attack the Yankees They not only declined this, but those on the right and left almost mutinied because their officers would not surrender. They were only reassured and persuaded to continue on duty by being told that they had provisions enough on hand to last seven days. In that time they would have 2000 boats finished, and they could make their escape by the river. The rebel said they were tearing down houses to get the material out of which to build boats. I will direct Mower (Gen) to keep a strong Picket in the river in front of Vicksburg at night, to place his battery behind the levees or hold it in some good position to be used if an attempt should be made to escape in that way. If possible fix up Material to light and illuminate the river should a large number of boats attempt to cross. I will direct Gen Mower to call on you, and consult as to the best plan for defeating this method of escape. You will find Gen Mower an intelligent and gallant officer, capable of carrying out any plan that may be adopted

Very truly your Obt Servt

U. S. Grant 

Maj. Genl.

SOURCE: John Y. Simon, Editor, The Papers of Ulysses S. Grant, Volume 8, p. 398-9