In the mean time Beauregard had been gathering reinforcements.

On the 16th he attacked Butler with great vigor, and with such success as to limit very materially the further usefulness of the Army of the James as a distinct factor in the campaign.

I afterward ordered a portion of it to join the Army of the Potomac, leaving a sufficient force with Butler to man his works, hold securely the footing he had already gained and maintain a threatening front toward the rear of the Confederate capital.
The position which General Butler had chosen between the two rivers, the James and Appomattox, was one of great natural strength, one where a large area of ground might be thoroughly inclosed by means of a single intrenched line, and that a very short one in comparison with the extent of territory which it thoroughly protected.

His right was protected by the James River, his left by the Appomattox, and his rear by their junction--the two streams uniting near by.

The bends of the two streams shortened the line that had been chosen for intrenchments, while it increased the area which the line inclosed.
Previous to ordering any troops from Butler I sent my chief engineer, General Barnard, from the Army of the Potomac to that of the James to inspect Butler's position and ascertain whether I could again safely make an order for General Butler's movement in co-operation with mine, now that I was getting so near Richmond; or, if I could not, whether his position was strong enough to justify me in withdrawing some of his troops and having them brought round by water to White House to join me and reinforce the Army of the Potomac.