Appendix B: correspondence between General Halleck and General Meade, after the battle of Gettysburg, July 7-10, 1863, mentioned in letter of July 10, 1863. see page 133, Vol. II
President the following note, which I respectfully communicate.
Vicksburg surrendered to Genl. Grant on the 4th of July. Now, if Gen. Meade can complete this work, so gloriously prosecuted thus far, by the literal or substantial destruction of Lee's Army the rebellion will be over. Yours truly
Gettysburg, follow it up and give him another before he can cross the Potomac. When he crosses circumstances will determine whether it will be best to pursue him by the Shenandoah Valley or this side of Blue Ridge. There is strong evidence that he is short of Artillery ammunition and if vigorously pressed he must suffer.
Gen. Couch of 4.30 P. M. You are perfectly right. Push forward and fight Lee before he can cross the Potomac.
Williamsport. The opportunity to attack his divided forces should not be lost. The President is urgent and anxious that your Army should move against him by forced marches.
Gen'l Couch learns from scouts that the train is crossing at Williamsport very slowly. So long as the river is unfordable the enemy cannot cross. My cavalry report that they had a fight near Funkstown, through which they drove the enemy to Hagerstown, where a large infantry force was seen. From all I can gather the enemy extends from Hagerstown to Williamsport covering the march of their trains. Their cavalry and infantry pickets are advanced to the Hagerstown and Sharpsburg pike, on the general line of the Antietam. We hold Boonsboro, and our pickets, four miles in front, toward Hagerstown, are in contact with the enemy's pickets. My Army is assembling slowly; the rains of yesterday and last night have made all roads but pikes almost impassable. Artillery and wagons are stalled; it will take time to collect them together. A large portion of the men are barefooted. Shoes will arrive at Frederick today and will be issued as soon as possible. The spirit of the Army is high; the men are ready and willing to make any exertion to push forward. The very first moment I can get the different commands, the artillery and cavalry, properly supplied and in hand, I will move forward. Be assured I most earnestly desire to try the fortunes of war with the enemy on this side of the river, hoping, through Providence and the bravery of my men to settle the question, but I should be wrong not to frankly tell you of the difficulties encountered. I expect to find the enemy in a strong position, well covered with artillery, and I do not desire to imitate his example at Gettysburg and assault a position when the chances are so greatly against success. I wish in advance to moderate the expectation of those who, in ignorance of the difficulties to be encountered, may expect too much. All that I can do under the circumstances, I pledge this Army to do.
Funkstown and Williamsport. I have just received information  that he has driven in my cavalry force in front of Boonsboro. My Army is and has been making forced marches, short of rations and barefooted. Our Corps marched yesterday and last night over 30 miles. I take occasion to repeat that I will use my utmost efforts to push forward this Army.
Harpers Ferry that the enemy have been crossing for the last two days. It is also reported that they have a bridge across. If Lee's Army is divided by the river the importance of attacking the part on this side is incalculable—such an opportunity may never occur again. If on the contrary he has massed his whole force on the Antietam time must be taken to also concentrate your forces—Your opportunities for information are better than mine. Brig. Gen. Kelly was ordered some days ago to concentrate at Hancock and attack the enemy's right. Maj. Gen. Brooks is also moving from Pittsburgh to reinforce Kelly. All troops arriving from New York and Fort Monroe are sent directly to Harpers Ferry unless you order differently. You will have forces sufficient to render your victory certain. My only fear now is that the enemy may escape by crossing the river.
Boonsboro to Rohrersville. Two Corps will march without their artillery, the animals being completely exhausted, many falling on the road. The enemy's infantry were driven back yesterday evening from Boonsboro, or rather they retired on being pressed, towards Hagerstown. I am still under the impression that Lee's whole force is between Hagerstown and Williamsport, with an advance at Middleburg, on the road to Greencastle, observing Couch. The state of the river and the difficulty of crossing has rendered it imperative on him, to have his army, artillery and trains, ready to receive my attack. I propose to move on a line from Boonsboro towards the centre of the line from Hagerstown to Williamsport, my left flank looking to the river, and my right towards the mountains, keeping the road to Frederick in my rear and centre. I shall try to keep as concentrated as the roads by which I can move will admit, so that should the enemy attack, I can mass to meet him, and if he assumes the defensive, I can deploy as I think proper. I transmit a copy of dispatch sent to Gen. Smith at Waynesboro; one of like tenor was sent to Gen. Couch. The operations of both these officers should be made to conform to mine. They can readily ascertain my  progress from scouts and by the movements of the enemy; and if the forces under them are of any practical value, they could join my right flank and assist in the attack. My cavalry will be pushed to-day well to the front on the right and left, and I hope will collect information. It is with the greatest difficulty that I can obtain any reliable intelligence of the enemy. I send you a dispatch received this A. M. from Gen. Neill, in command of a brigade of infantry and one of cavalry, who followed the retreat of the enemy through Fairfield and effected a junction with Gen. Smith, at Waynesboro. A copy of my dispatch to Gen. Smith is also sent you. When I spoke of two Corps having to leave their batteries behind, I should have stated that they remained at Frederick to get new horses and shoe the others, and they will rejoin their Corps this P. M. The object of the remark was to show the delay. I think the decisive battle of the war will be fought in a few days; in view of its momentous consequences I desire to adopt such measures as, in my judgment, will tend to ensure success, even though these may be deemed tardy. 11.30 A. M.—A deserter has just been brought within our lines, who reported the enemy's army all between Hagerstown and Williamsport; that they have brought up a bridge from Winchester, which is now thrown across at Williamsport; that they are using this bridge, not to cross their forces, but to bring over supplies; that the men are in fine spirits, and the talk among them is, they mean to try it again. This deserter says he belongs to the artillery of Stuart's command. I send the information for what it is worth.
Lee's army will fight north of the Potomac seems reliable. In that case you will want all your forces in hand. Kelley is collecting at Hancock. I have directed him to push forward, so as to take part in the coming battle. Brooks' militia refused to cross the Pennsylvania line. Everything I can get here will be pushed on to Harper's Ferry, from which place you can call them in to your left. Do not be influenced by any dispatch from here against your own judgment. Regard them as suggestions only. Our information here is not always correct. Take any horses or supplies you can find in the country. They can be settled for afterward. Would it not be well to fortify the Hagerstown Gap, through the South Mountain as a part of the support?
Harpers Ferry unless you wish otherwise. I shall do everything in my power to reinforce you. I fully appreciate the importance of the coming battle.
Potomac, near Falling Water, through Downsville to Funkstown and to the northeast of Hagerstown, Ewell's Corps being to the northeast of Hagerstown, Longstreet's at Funkstown and A. P. Hill's on their right. These positions they are said to be intrenching. I am advancing on a line perpendicular to the line from Hagerstown to Williamsport, and the Army will this evening occupy a position extending from the Boonsboro and Hagerstown road, at a point one mile beyond Beaver Creek, to Bakersville, near the Potomac. Our cavalry advance this morning drove the enemy's cavalry, on the Boonsboro pike, to within a mile of Funkstown, when the enemy deployed a large force and opened a fire from heavy guns (20-pounders). I shall advance cautiously on the same line to-morrow until I can develop more fully the enemy's position and force, upon which my future operations will depend. General Smith is still at Waynesboro; a dispatch was received from him at that place, this morning. Instructions similar to those of yesterday were sent to him.
Monocacy to direct the troops arriving where to go and see that they are properly fitted out. They should join you by forced marches. Beware of partial combats, bring up and hurl upon the enemy all your forces, good and bad.