or ordered. The movement of your re-enforcements by railroad has probably delayed the transportation of some portion of them. It is difficult to supply the waste of horses.

H. W. HALLECK,

General-in-Chief.

HEADQUARTERS ARMY OF THE POTOMAC,
October 13, 1862-7 p.m.

Major-General HALLECK, General-in-Chief:

The recent raid of Stuart, who, in spite of all the precautions I could take with the means at my disposal, went entirely around this army, has shown most conclusively how greatly the service suffers from our deficiency in the cavalry arm. The great extent of the river line from Washington to Cumberland, the major portion of which at the present stage of water is fordable at almost every point, renders it necessary to scatter our cavalry for a very great distance in order to watch the numerous crossings. At the time Stuart crossed, it so happened that the greater part of our cavalry was absent, near Cumberland, in pursuit of another rebel cavalry force, which had made its appearance at the little Cacapon and other points on the Upper Potomac, destroying railroad bridges, &c. I had pickets at McCoy's Ferry, where Stuart crossed, but they were captured by his men, and, in consequence of this, I did not learn of the crossing for some hours afterward. All the cavalry that could be collected to pursue Stuart only amounted to less than 1,000 men. With these Pleasonton marched 78 miles in twenty-four hours, with a horse battery, but only came up with Stuart at the Potomac after he had marched over 90 miles during the same time, with change of horses. The track of the rebels was entirely outside of our infantry, until he came near General Stoneman, at Poolesville, who has not, as yet, explained why he did not mass his troops and engage him, as he was ordered. The rapid movement of the rebel cavalry precluded the possibility of marching out infantry from any point of our lines with a probability of intercepting them.

Cavalry is the only description of force that can prevent these raids. Our cavalry has been constantly occupied in scouting and reconnaissances, and this severe labor has worked down the horses and rendered many of them unserviceable, so that at this time no more than one-half of our cavalry are fit for active service in the field. The enemy is well of our cavalry are fit for active service in the field. The enemy is well provided with cavalry, while our cavalry force, even with every man well mounted, would be inadequate to the requirement of the service and to the large infantry force with the army. I, therefore, again most strenuously urge upon the Department the imperative necessity of at once supplying this army, including the command of General Banks, with a sufficient number of horses to remount every dismounted cavalry soldier within the shortest possible time. If this is not done we shall be constantly exposed to rebel cavalry raids.

GEO. B. McCLELLAN,

Major-General.

FAIRFAX COURT-HOUSE,

October 13, 1862-8.30 p.m. (Received 8.45 p.m.)

Major-General HEINTZELMAN:

No change of importance in the enemy's position and strength has taken place before our front. Yesterday Captain Koenig returned, who

27 R R-VOL XIX, PT II