Do send back our cavalry which got into Pennsylvania; we require it. If I have this command, with all the cavalry which is said to have escaped into Pennsylvania, I can do something. I can do something here by keeping the cavalry between this and Winchester. I brought off 1 gun, 2 caissons, and 1 limber, 1 lieutenant, 48 men, and 29 horses of Maulsby's battery. I hear three pieces, with the captain, got off toward Williamsport, which I doubt. All my disposable cavalry are on their way to the Monocacy. Captain Woodhull will return to Baltimore soon. He behaved gallantly at Martinsburg. The aggregate of Milroy's men here is 1, 558.

DAN. TYLER,

Brigadier-General.

BALTIMORE, MD., June 18, 1863-1 p. m.

H. W. HALLECK,

General-in-Chief:

I have kept General Tyler instructed to have cavalry patrols constantly on the Potomac from Harper's Ferry to the mouth of the Monocacy, but I have no infantry to guard ferries of fords.

ROBT. C. SCHENCK,

Major-General.

(Copy to General Hooker.)

HEADQUARTERS ARMY OF THE POTOMAC,
June 18, 1863-2 p. m.

General TYLER, Sandy Hook:

We would like to know the names of all the generals that the prisoner can give, no matter what their commands are. What does hi think has become of Longstreet? Ewell commands Jackson's old corps, with one division taken out to give to A. P. Hill. Rodes has a division under Ewell. Jones, Imboden, and Jenkins commanded small forces in the Valley prior to the departure of Lee's forces, and have doubtless joined Ewell. Give us the name and locality certain at any time of any regiment of infantry.

DANL. BUTTERFIELD,

Major-General, Chief of Staff.

SANDY HOOK, MD., June 18, 1863-10 p. m.

Major-General HOOKER:

I have information which I deem reliable that Rodes and his division were not in Williamsport yesterday, the 17th instant. I have a pass signed by him at that time, and countersigned to-day by Jones at Sharpsburg. Three regiments belonging to Jones' division, and about 100 cavalry, passed over the ford, about 1 mile below Shepherdstown, at 4 o'clock to-day. There was no artillery with them. I have reason to suppose that before these men passed the ford to-day, Jones had three regiments and some cavalry about three-quarters of a mile from Sharpsburg, on the road toward Antietam.