Review of the Judge- Advocate-General of the record of the court of inquiry relative to the evacuation of Martinsburg by the command of Brigadier General Daniel Tyler.

JUDGE- ADVOCATE- GENERAL'S OFFICE, Washington, D. C., September 17, 1863.

The record of a court of inquiry lately convened to investigate the facts and circumstances connected with the evacuation of Martinsburg by the command of Brigadier General D. Tyler, U. S. Volunteers, having been submitted to me under your indorsement of the 12th instant, has been fully reviewed, and I have the honor to report the following summary of facts, with the` conclusions derived therefrom: Up to June 13, the United Stated forces at Martinsburg, Va., had been for several months under the command of Colonel B. Smith, whose detachment consisted of two regiments of infantry, eight companies each, one field battery, and rather more than a company of cavalry; in all, about 1, 300 men. Martinsburg was not fortified post. On the 13th, a written order was issued by Major-General Schenck to Brigadier-General Tyler, by which he was required to assume command of the troops at Martinsburg, for the purpose of them to support and cover the retreat of Major-General Mirloy from Winchester to Harper's Ferry. Details of the service are left to the discretion of General Tyler, but Bunker Hill is suggested as a suitable position at which to make a stand if the rebels be found in force between his own troops and those of Mirloy. General Tyler is required to keep constantly in communication meanwhile with General Mirloy. Pursuant to this order, General Tyler proceeded from Baltimore, by way Harper's Ferry, to Martinsburg, where he arrived about 8 o'clock on the morning of the 14th, when he found Colonel Smith just taking out his troops to meet an advance of the enemy, who were already skirmishing with his pickets. In his official report, General Tyler says that he went to Martinsburg "to relieve Colonel Smith in the command of the Third Brigade, " but he states that, on arriving, he concluded not to assume the command. In his testimony he sets forth his reason for this course as following:First. Because the command was not commensurate with his rank, and was not equal to the expectations which he hat formed of it when leaving Harper's Ferry. Secondly. Because he was a perfect stranger to the command, and it would be "more for the good of the service for Colonel Smith to fight the battle which was already begun . "He nevertheless, as he says, notified Colonel Smith that he would give him any advice that he might require . However insufficient these reasons, especially the first, may be considered, there was received by General Tyler about noon intelligence which rendered it necessary for him to take the command, at least for the special purpose of carrying out the instructions contained in the order of General Schenck . This was the intelligence that General Milroy had been attacked by Lee's army in greatly superior force, and that Bunker Hill situated between Martinsburg and Winchester, had been occupied by the enemy . It would been useless, therefore, for General Tyler to have attempted with his small force to make a diversion in favor of General Milroy. Indeed, his orders from General Schenck had been predicated on the supposition that Milroy