WASHINGTON, May 31, 1862.

General MCDOWELL:

The following has just been received:

WILLIAMSPORT - 11.40 p. m.

Honorable E. M. STANTON:

We have no report from our forces at Martinsburg to-night. It is quite possible that the demonstration of the rebels against Harper's Ferry is to cover their retreat. They operate between Charlestown and Berryville. Early in one movement covers Snickersville Ferry. This will take them east of the Blue Ridge. They are probably preparing means of crossing at that point. All their fury and numbers are well spent at Harper's Ferry for that purpose.

N. P. BANKS,

Major-General.

[EDWIN M. STANTON.]

[MAY 31, 1862.]

Brigadier-General WADSWORTH:

I promised the commanding officer at Catlett's a small body of cavalry. The going off the Michigan cavalry leaves me unable to fulfill my promise without injury to the service near the enemy. In my judgment Washington will be as safe without this cavalry as with it, and Catlett's will not be. But I do not wish to run the risk of a censure for stripping Washington, and therefore ask if this may be done if the War Department consents.

IRVIN MCDOWELL,

Commanding Department.

[MAY 30 or 31, 1862.]

Brigadier-General KING,

Commanding Division:

One train left Manassas for your command at 8.30 a. m. Another is just leaving. A third to follow immediately. The others from this place are just about leaving. There are nine trains in all. Let no time be lost in getting the men on the cars, and let the train move off as the railroad dispatcher may indicate, so as to avoid collisions. Let your infantry go to Piedmont, about 5 miles from this place, or as much farther. Let your cavalry keep with your artillery and train. Major Duffie was fired on repeatedly from Catlett's to Thoroughfare, even from the houses. Some of the grades from Thoroughfare to this place are heavy, though short, and it may be necessary for the men to leave the train whilst they are ascending.

IRVIN MCDOWELL,

Major-General, Commanding.

CATLETT'S, May 31, 1862.

General MCDOWELL:

First train just arrived. Infantry all here, and drawing their rations. Will load up and dispatch train as fast as we can. Shall we not need infantry as well as cavalry to go with artillery and subsistence train