Soon after dark some of the cavalry at Long Bridge effected a crossing by wading and floundering through the water and mud, leaving their horses behind, and drove away the cavalry pickets.  A pontoon bridge was speedily thrown across, over which the remainder of the army soon passed and pushed out for a mile or two to watch and detain any advance that might be made from the other side.  Warren followed the cavalry, and by the morning of the 13th had his whole corps over.  Hancock followed Warren.  Burnside took the road to Jones’s Bridge, followed by Wright.  Ferrero’s division, with the wagon train, moved farther east, by Window Shades and Cole’s Ferry, our rear being covered by cavalry.

It was known that the enemy had some gunboats at Richmond.  These might run down at night and inflict great damage upon us before they could be sunk or captured by our navy.  General Butler had, in advance, loaded some vessels with stone ready to be sunk so as to obstruct the channel in an emergency.  On the 13th I sent orders to have these sunk as high up the river as we could guard them, and prevent their removal by the enemy.

As soon as Warren’s corps was over the Chickahominy it marched out and joined the cavalry in holding the roads from Richmond while the army passed.  No attempt was made by the enemy to impede our march, however, but Warren and Wilson reported the enemy strongly fortified in their front.  By the evening of the 13th Hancock’s corps was at Charles City Court House on the James River.  Burnside’s and Wright’s corps were on the Chickahominy, and crossed during the night, Warren’s corps and the cavalry still covering the army.  The material for a pontoon bridge was already at hand and the work of laying it was commenced immediately, under the superintendence of Brigadier-General Benham, commanding the engineer brigade.  On the evening of the 14th the crossing commenced, Hancock in advance, using both the bridge and boats.

When the Wilderness campaign commenced the Army of the Potomac, including Burnside’s—­which was a separate command until the 24th of May when it was incorporated with the main army—­numbered about 116,000 men.  During the progress of the campaign about 40,000 reinforcements were received.  At the crossing of the James River June 14th-15th the army numbered about 115,000.  Besides the ordinary losses incident to a campaign of six weeks’ nearly constant fighting or skirmishing, about one-half of the artillery was sent back to Washington, and many men were discharged by reason of the expiration of their term of service.* In estimating our strength every enlisted man and every commissioned officer present is included, no matter how employed; in bands, sick in field hospitals, hospital attendants, company cooks and all.  Operating in an enemy’s country, and being supplied always from a distant base, large detachments had at all times to be sent from the front, not only to guard the base of supplies and the roads to it, but all the roads leading to our flanks and rear.  We were also operating in a country unknown to us, and without competent guides or maps showing the roads accurately.