The Eight and Seventy-first Regiment New York State National Guard, and one regiment of Pennsylvania militia, having been sent forward, under command of General Knipe, by the Cumberland Vallet Railroad to Shippensburg, and having fallen back from point to point as they were driven in by the rebels, presented the appearance of an advance guard of a large force, delayed the rebels a week or more in their advance, and enabled many other regiments to arrive at Harrisburg, and to throw up to quite formidable earthworks, to erect barricades across the roads through the mountain gaps, and to dig rifle-pits and make other defensive preparations . My hospital surgeon, Major E. Maloe, joined me here, and his services were very valuable at the hospital established near the fort . The entire force was constantly employed night and day, as the regiments arrived, in erecting these earthworks, barricades, &c., and in picket duty, and were saved from an attack from Lee's army by the delay in its advance, occasioned by the militia force and demonstration, until the morning of the 30th of June . After having driven in our outer line of pickets, the rebels fell back under orders, as appears by General Lee's report, to meet the Army of the Potomac at Gettysburg. On the 1st of July, the Twenty-second and Thirty-seventh New York State National Guard, with two regiments of Pennsylvania militia, and a battery of citizens artillery from Philadelphia entered Carlisle, 18 miles from Harrisburg, down the Cumberland Valley, and were that night shelled by Stuart's cavalry, who burned the Carlisle barracks and other buildings . The militia stood their ground nobly, and the artillery is said to have done good service in the defense of the place . On the afternoon of the 1st of July, my three regiments, with the Eight, Eleventh, and Seventy-first Regiments New York State National Guard, and Miller's light battery, attacked temporarily to the Eight Regiment National Guard, marched out from the fort opposite Harrisburg on the road toward Carlisle, the whole under the command of General Knipe, and went into camp, or rather into a field 7 miles from the fort, at about 9 o'clock in the evening . As we went into quartermaster, heavy cannonading was heard in the direction of Carlisle, and the light of the burning barracks was distinctly visible on the sky. This was as anxious night to our command, as the supposition was that Ewell's corps of Lee's army had returned to Carlisle, and attacked our militia there in force, and would capture them, and be down upon us the next morning . We had no intimation that on that day there had been a battle of Gettysburg . At 2 o; clock the next morning, a staff officer came in from General Couch, with orders to get the baggage train back on the road to Harrisburg, and to have the men in readiness to march at a moment's notice . At a 3 a. m. another officer came from General Couch, with peremptory orders to march back at once to the fort. Three retreat was then commenced, and continued for about 3 miles . We were then halted in the road, and remained there until near sundown, when we bivouacked on the bank of a beautiful stream for the night, and the next day (July 3) marched to Carlisle, about 15miles. The weather was very warm, the men marched with their knapsacks packed, their blankets rolled, their haversacks supplied with two days ' ration, and their cartridge-boxes with 40 rounds . The suffered greatly from this first march, and were compelled to leave their knapsacks and many other things that were afterward much needed .