On the 15th General Hunter arrived at Harper's Ferry, and he made a new disposition of troops to guard the Valley. General Sullivan was sent toward Leesburg, and I sent Sergeant Strong to him to communicate by way of Maryland Heights, having no officer to send. Having heard that General Wright was at Poolesville, I reported it to General Hunter, and suggested the practicability of opening communication with him. General Hunter desired me to do so, and at 3.30 p.m. I started with Lieutenant Fortney and twenty men, and reached Poolesville at 12.30 a.m. and opened communication by way of Sugar Loaf Mountain, Point of Rocks, and Maryland Heights.
On the morning of the 16th General Wright requested me to carry some dispatches and some verbal information to General Hunter; so leaving Lieutenant Fortney at Poolesville, with orders to remain till Wright's corps had passed, and then when he could to communicate with Wright to return to department headquarters, I returned to Harper's Ferry. General Crook having relieved Sullivan, occupied Hillsborough, and we were in communication with him through the Maryland Heights.
On the 17th Lieutenant A. W. Bariteau, Fifth New York Artillery, having been detailed by General Howe, I had the order confirmed by General Hunter. General Wright having crossed the Catoctin Mountain communicated direct with Maryland Heights, and I discontinued the stations at Poolesville and Sugar Loaf.
Having had no communication with Wright during the 18th and 19th, General Hunter directed me to go with a party and learn his movements if possible. Accordingly I started, and that night (19th) bivouacked at White's Ferry. On the 20th I learned that he had gone through Snicker's Gap, and no communication could be had with him, so I returned on the 21st. That day I sent Lieutenants Jones and Butcher to General Crook, and Muhleman to Averell.
On the 22nd I went to Martinsburg and got some stores, and that evening returned to Harper's Ferry. Having got news of the death of a friend making my presence necessary, I obtained leave of absence for four days (from the 23d).
On the 28th I reached headquarters on my return, having been delayed at Baltimore by trains moving irregularly in consequence of rebel raids on the railroad. On arrival I found that the enemy had driven our forces out of Martinsburg. All the signal detachment but Lieutenant Muhleman was at headquarters, under Lieutenant Thayer, who had them in good condition. I got all in readiness to march, drew stores, and rearranged the working parties and the reserve. General Wright's troops had moved in and halted at Halltown.
On the 30th General Hunter's whole command, which now included Wright's troops, was put on march toward Frederick City. At Weverton, on his suggestion, I sent Lieutenant Thayer with Lieutenant Jones and twenty men to Frederick, thence to go to the Catoctin Mountain and get any news of the enemy. If no enemy was found this side of the Catoctin, to go along the range in the morning in the direction of Gettysburg and report often, by signal when practicable, and at other times by courier. To-night headquarters halted at Knoxville.
On the 31st we reached Frederick, and the troops were encamped in front and rear of city. Thayer reported from Frederick while on the march that no enemy was there, and he would go on toward