HEADQUATERS,

Maryland Heights, June 17, 1863-9. 45 a. m.

Lieutenant-Colonel Piatt,

Chief of Staff:

My force at night are all on Maryland Heights. During the day I hold Harper's Ferry with my forces . I don't believe there are 250 rebels in any place short of Williamsport; there, I am satisfied, they have 7, 000 or 8, 000 infantry and artillery, while the cavalry is running into Pennsylvania . We use Sandy Hook only because the operator thinks it more safe than Harper's Ferry.

Dan. Tyler,

Brigadier-General.

Troops ordered under arms at 3 o'clock to-morrow morning. June 18. -Received telegrams from Major-General Hooker, which were answered by the following:

Headquarters, Maryland Heights, June 17, 1863.

(Received War Department, June 17-5p. m.)

Major-General Hooker, Commanding Army of the Potomac:

The only rebel force of any amount than I satisfied of was at Williamsport at 6 o'clock last evening. I think, allowing for exaggerations, there might be 7, 000 or 8, 000 men of all arms at Williamsport . The impression made on my mind is that their infantry and artillery are holding on in Maryland, while the cavalry and light batteries are pushed into Pennsylvania. This is merely my opinion . I wish I could back it up by facts, but I can't . Audacity is the capital on which the rebels win, and I hope by and by to see this game lose. This heading off is a losing game, in my opinion. The only way is to follow, and take the consequences.

Dan. Tyler,

Brigadier-General.

HEADQUATERS,

Maryland Height, June 18, 1863.

Major-General Hooker, Commanding Army of the Potomac:

The manes of Ewell's division commanders, as given by General Elliot, are as follows:E. Johnson, Rodes, Early, Walker, and A. P. Hill. One of the prisoners told General Elliot that Longstreet was going into West Virginia. This is the only information we have of Longstreets. General Jones, Imboden, and Jenkins as I telegraphed you, had joined Ewell, Jenkins signed the summons to surrender at Martinsburg. At Charlestovn, Rodes signed a paper demanding the surrender of a company of cavalry, and sent it by a flag. The company got off. At martinsburg, the attack was made by one six-gun battery and by infantry and cavalry. The attack on the train at Point of Rocks was made by White's cavalry, say 150 men. White crossed over near the Catoctin, and recrossed after a skirmish with Mean's company of a our cavalry. White is now somewhere in Loudoun. I am trying to get at him. My cavalry has gone to Point of Rocks to-day in all the force I venture to send forward . I have no reports of it as yet . If there is an object, I might venture to send a brigade of infantry to guard Noland's Ford, but I cannot afford to risk it. There is at this moment, as far as I can ascertain, no considerable rebel force threatening this position.

Dan. Tyler,

Brigadier-General .

Engineer detail to=day 1, 500 men, and all the troops were engaged in throwing up breastworks, constructing rifle-pits, and in the immediate forts. Found great de ficiency in intrenching tools, axes, &c. ; telegraphed to the quart ermaster at Baltimore for them; borrowed provisions on to the Maryland Heights, and directed the means to obtain water there to be attended to and increased. Not satisfied with the outer infantry pickets, and ordered a dozen cavalry to each picket. Troops were ordered under arms at 3 a. m. to-morrow.