It will be necessary for him to keep his cavalry active, and instruct men and officers to be steady, and to oppose vigorously the advance of any parties that may present themselves. I do not believe the force can be large; probably only some cavalry.

It would be an unwise measure for a small body of infantry to attempt to force its way through this army to join the main body of the enemy, which is certainly beyond South Mountain. I do not think they will attempt it.

You must turn over this matter to Colonel Imboden, and yourself attend to getting the prisoners on to Staunton as soon as possible. I hope you will bend all your energies to this subject, and get him along with as much expedition and comfort as circumstances will permit.

I have direct Lieutenant-Colonel [Thomas B.] Massie to advance a portion of his cavalry from Charlestown to Martinsburg, to give additional security to your movement; so you may look out for him.

I desire you to organize the companies of which you spoke yesterday, as soon as possible, and collect all your serviceable men, and get back to this army as soon as you can.

Unless Colonel[H. B.] Davidson can place a guard at the Shenandoah Mountain, you will still have to retain guard at that point, with directions to report to him. You must take as small a guard from General Pickett`s command as you can possibly do with, and carry it no farther than Winchester, as we want every man now with this army.

I presume your battery that operates with your cavalry is mounted as horse artillery. If so, it will require no support but the cavalry itself.

If they have more guns than they require, the surplus can be sent back to Williamsport.

It will be necessary for Colonel Imboden to picket well out on the road, or he will be of no service whatever. He must throw his pickets well out, and keep his men on the alert, and not suffer them to be surprised or taken. His operations must be conducted with boldness and prudence. I regret to hear that a part of his men deserted some wagons when threatened by the enemy, which as far as reported to mo, was not necessary. I do not know the facts, but mention the report to call the attention of Colonel Imboden to it, in order that he may inquire into it, and prevent the repetition of such conduct.

Very respectfully, your obedient servant,

R. E. LEE,

General.

MARTINSBURG, July 9, 1863.

The PRESIDENT:

General Lee`s headquarters are at Hagerstown. He is said to be waiting there for ammunition, which has just passed this place. I cannot tell whether he intends to recross the river or to advance. No news from the enemy`s army. The Yankees have reoccupied Maryland Heights at Harper`s Ferry, it is supposed with a brigade. The rear cavalry skirmishing every day. The prisoners not paroled are at the river. River falling.

F. C. ROBERTS,

Captain, Commanding Post.