Alexandria. It has occurred to me that his object may be to seize upon Strasburg with his main force, to intercept your ascent of the valley. This would oblige you to cross into the Lost River Valley, or west of it, unless you could force a passage through the Blue Ridge; hence my anxiety for your safety. If you can prevent such a movement of the enemy, and operate strongly upon his flank and rear through the gaps of the Blue Ridge, you would certainly, in my opinion, effect the object you propose. A demonstration of crossing into Maryland would serve the same purpose, and might call him back to the Potomac. As my object is to retard and baffle his designs, if it can be accomplished by maneuvering your corps as you propose, it will serve my purpose as well as if effected in any other way. With this understanding, you can use your discretion, which I know I can rely upon, in remaining of advancing upon the valley. But I desire you will take precautions of prevent the enemy's occupying the roads west of the Massanutten Mountains, and your demonstration upon his flank might probably be as well made from a position nearer to Strasburg as from that you now occupy. If the enemy should move into the valley through Thornton's Gap, you must seize the pass through the Massanutten Mountains as soon as you can, while Longstreet will advance through Milman's, which you term Fisher's Gap (on the direct road from Madison Court-House to New Market). But I think his movement upon Front Royal the more probable of the two.
Keep me advised of your movements and intentions; and you must keep always in view the probability of an attack upon Richmond from either north or south, when a concentration of forces will become necessary. The enemy has made no advance south of the Rappahannock line since 1 last wrote you.
Colonel Corley has just returned from Staunton, and says that he has sent you shoes and blankets, which I hope you will soon receive and find sufficient for the necessities of your command. They may have been stopped at New Market with the expectation of your advancing up the valley; if so, send and get them, and use every exertion to insure the hearth and comfort of your men.
I am much gratified at the conduct of Major White, and I desire you to express to General A. P. Hill my appreciation of his conduct.
The non-occupation of Martinsburg by the enemy, and his not marching into the valley from his formed base on the Potomac, shows, I think, that his whole force has been drawn from Maryland into Virginia east of the Blue Ridge. His retirement from Snicker's and Ashby's Gaps, and concentration of his force on the railroad in the vicinity of Manassas Gap, must either be for the purpose of supplying it, or for making a descent upon Front Royal and Strasburg. I hope, therefore, you will be on your guard.
I am, &c.,
R. E. LEE,
HEADQUARTERS ARMY OF NORTHERN VIRGINIA,
November 9,  - 10 p. m.
Major General J. E. B. STUART,
Commanding Cavalry, &c.:
GENERAL: I find from dispatches from General Jackson that the enemy has abandoned Snicker's and Ashby's Gaps and concentrated his main force along the Manassas Gap Railroad, in the vicinity of Piedmont,