The major-general commanding is informed that, agreeably to your request, General Sedgwick placed at your disposal a brigade of infantry, and he desires to know why these orders were not complied with and those bridges laid at the hour specified.

Very respectfully, & c.,

S. WILLIAMS,

Assistant Adjutant-General.

Brigadier-General BENHAM,

Commanding Engineer Brigade.

HEADQUARTERS ENGINEER BRIGADE,
Near Falmouth, Va., April 29, 1863.

SIR: I have the honor to acknowledge your letter of this date, giving an extract from the orders of the commanding general, which stated that I was charged with placing the bridges, two at each crossing, to be laid complete before 3.30 a. m. of the 29th, directing me to state why those orders were not complied with. To show how completely every effort on my part was made to accomplish this, and through what causes it failed, as far as known, a statement somewhat in detail may be necessary, though it is summed up in a few words at the close of this letter.

These orders were communicated to me about 11 a. m. yesterday morning, as I was mounted to go to General Sedgwick's camp, I having about one hour previously been shown by General Butterfield a press copy of the original in the adjutant-general's office, and immediately after my return to my camp, and finding an aide of General Sedgwick's, I communicated through him by note the main features of my project for laying the bridges. On meeting General Sedgwick, it was agreed to, or approved by him as follows: I proposed to use all the boats of the three bridges, or about one hundred in number, which it was estimated would carry about 6,000 men at a single trip, which number it was decided by General Sedgwick to throw over at each place, as I understood it, before laying the bridges. To avoid the alarm and consequent preparation for us, which the sound of the pontoon boats might give to the enemy long before we could reach the river bank, I proposed (having previously drawn the pontoons to the edge of the woods by animals) to have the boats carried from these points, about two-thirds of a mile, to the river, by the men of the command, which it was judged 72 men for each boat, forming double reliefs, could easily do. Captain Reese having reported to me that on trial he had found that 36 men were ample to carry each boat to the river, with one rest; that as soon as it could be discovered that the enemy had taken the alarm, the pontoon equipage on its trucks, preceded by the protecting artillery, should be ordered to come down rapidly, during the crossing of which the boats, manned by oarsmen from the engineers (and with each its crossing party of 60 men, previously assigned, who should be with each boat, with an equal force awaiting there for a second trip), were to be put in the river and thrown to the opposite bank. The equipage was expected to be down by the time of the second return of the boats, when the laying of the bridges was to be commenced.

The pontoons were to be, and were, closed up at the edge of the woods at twilight, or soon after. It was judged best not to commence too early, not to alarm the enemy before the usual hour of rest. The hours were carefully discussed with General Sedgwick, and I judged that,