No. 27. Reports of Colonel George B. Dandy, One hundredth New York Infantry, of operations May 7 and June 1-2.

HEADQUARTERS 100TH NEW YORK VOLUNTEERS, In the Field, May 8, 1864.

SIR: I have the honor to make the following report of the part my regiment took in the attack made by the Third Brigade, Terry's division, on the enemy yesterday:

The design was to cut the Richmond and Petersburg Railroad, and destroy as much of it as possible. It was understood, the enemy being in good defensive positions overlooking the railroad, that the movement to be successful must be masked as much as possible, consistent wit the greatest celerity. The position of the brigade before the movement commenced was on an old road in a wood, the direction of the road being about northeast by southwest, while the railroad was north and south. I was directed by Colonel Plaisted, commanding the brigade, to make a detour, starting a little north of west, in order to take advantage of a wood which would mask the movement of the column.

I succeeded in getting through this wood with some difficulty, keeping Company I, Captain Brunck, deployed as skirmishers well to our right to warn us of the approach of the enemy in that direction. He marched and crossed the railroad, performed his duty with credit, and speaks well of the conduct of his officers and men. I finally emerged on a road running east and west, cutting vertically the Richmond turnpike, which at this point was about parallel with the railroad. On reaching the pike I found the woods in front, between the head of my column and the railroad, very difficult for skirmishers and impenetrable by any other description of troops. I therefore moved to the left on the turnpike until I found an open field, which, though swampy and cut by small streams, was practicable for infantry. Across this field, under a brisk fire from the enemy, I carried my colors, and, crossing the railroad, rallied my men on a height overlooking the rebel position and within short range of their advanced rifle-pits. The brigade of Colonel Barton was in the mean time advancing on our left and rear. A portion of his brigade, the Forty-eighth New York Volunteers, overlapping my regiment, joined me on the heights and planted its colors near the colors of the One hundredth New York Volunteers. We maintained this position for about two hours, repelled two successive charges of the enemy on our position, and materially aided Colonel Barton's brigade on our left, the enemy pressing upon them being checked by our fire on his flanks. In the mean time my regiment and the remaining two regiments of the brigade were engaged in tearing up the railroad and destroying the telegraph lines, both on the turnpike and railroad. This having been accomplished to a considerable extent - as far as I could see in the Richmond direction - and understanding that one or more trestle bridges had been destroyed, the brigade withdrew in sufficient time to prevent a flanking movement of the enemy on our left, caused by the falling back of Barton's brigade, and retook the position from which the movement was made. The object of the movement was successfully accomplished, and as far as I was able to judge great damage inflicted on the railroad and telegraph lines.