from duty with this army, and returned to Fort Monroe on the 3rd instant.
I am, very respectfully, your most obedient servant,
J. G. BARNARD,
Brigadier-General and Chief of Engineers, Army of the Potomac.
General J. G. TOTTEN, Chief Engineer, &c., Washington, D. C.
No. 3. Reports of Lieutenant Colonel Barton S. Alexander,
U. S. Army, Engineer Officer, of operations from April 20 to July 12.
WASHINGTON, D. C., January 28, 1863.
SIR: In compliance with your request I proceeded to give you a sketch of the operations upon which I was engaged during the time I was detached from your command, while the army was before Yorktown, until I again joined you at Cumberland, on the Pamunkey River:
On April 20, 1862, the army then being actively engaged in prosecuting the siege of Yorktown, I was directed by General McLellan to join General franklin as the engineer of his division, which had then arrived at Cheeseman's Landing. I had previously understood from the general that it was his intention at the proper time to throw General Franklin's division across to the north side of the York River, some 3 or 4 miles below Gloucester Point, and endeavor to seize the works there, or a least to turn them, and thus distract the attention of the enemy, while the main assault should be made at Yorktown.
A few days afterward Generals McLellan and Franklin, Captain Rodgers, of the Navy, and myself proceeded to reconnoiter the shore on the north side of the York River, and select, as near as possible, the exact spot where the proposed landing should be effected. This point being settled, I had some sounding taken to ascertain how near our transports could be taken to the shore, the depth of water, and nature of the bottom over the intervening space. I found that we could take vessels drawing 8 feet of water to within a certain distance-I think about 800 feet of high-water mark; that the bottom from this point to the shore was a very regular slope of sand, over which infantry could march when we should reach to within 250 feet of the shore, or to where the water was not over 2 feet 6 inches deep. This sand, however, was like that on the south shore of the river, and was of such a nature that I supposed it would not be prudent to trust artillery upon it, as there would have been danger of the carriages settling to their axle-trees. As soon as this information was obtained I set about preparing the means to effect a rapid landing when it should be ordered. Colonel J. McLeod Murphy, with a detachment of 250 men of the fifteenth New York Volunteer Engineer Regiment, was detailed to assist in these preparations.
Many schemes were proposed, which were thoroughly discussed by General Franklin, Captain Rodgers, of the Navy, Captain Arnold, of the artillery, and myself. As the plan which I finally decided to adopt was afterward successfully carried out at West Point, it may be proper to describe it here. In general terms it was this: We had a number (ten of twelve) of canal barges (boats, say, 14 feet wide and 70 to 80 feet long), drawing, when loaded, 5 feet of water; when light, 2 feet; of