As before stated, the dispositions for defense contemplated the whole of Wagner's division as the reserve to support the center, that being the only part of the line upon which the enemy would have time to make a heavy assault that day. This provision for an ample reserve had been made after full consideration and before Wood's division was ordered to the north side of the river, which was after the day was well advanced and the enemy's cavalry had begun to threaten the crossing above. The blunder respecting the two brigades of Wagner's division came near being disastrous, and the repulse of the assault in spite of that blunder makes it highly probable that if the dispositions ordered had been properly made, the repulse of the enemy would have been easy beyond reasonable doubt. Yet it would be difficult to find a fairer chance of success in a direct assault upon troops in position. Our intrenchments were of the slightest kind, and without any considerable obstructions in front to interfere seriously with the assault. The attack, no less than the defense, was characterized by incomparable valor, and the secret of its failure is to be found in one of the principles taught by all military experience--the great superiority in strength of a fresh body of troops in perfect order over another in the state of disorder which necessarily results from even the most successful assault. There was really no comparison, in effective strength, between Opdycke's orderly and compact brigade and the confused mass of Confederates that were crossing over our parapet. The result was nothing extraordinary or at all unprecedented. It was but one of the numerous proofs afforded by military history of the value of that prudent maxim in the art of war which dictates the placing of a suitable reserve in close support of that portion of a defensive line which is liable to heavy assault.