OFFICE PROVOST-MARSHAL-GENERAL, April 22, 1863. - Brig. Gen. S. WILLIAMS, Assistant Adjutant General, Army of the Potomac: - GENERAL: I made an examination in person of the picket lines....I find...that communications are kept up between the pickets across the river much of the time....From April 9 to the 12th, Lieutenant Castle, Sixty-second New York Volunteers, had command of the pickets, and during that time both he and his men had frequent conversations with the enemy's pickets by means of small sail-boats....On the night of the 15th, a conversation was carried on near Dr. Morrison's house...between the pickets...and the rebels. The first part of the conversation was about rations. Secesh then asked, "Any signs of a move?" Reply, "Yes, we have got eight days rations, and expect to move in a few days. We have three days rations in our haversacks and five in our knapsacks." Secesh then asked, "Where is the move to be?" Reply, "Up to the right." Secesh then asked how we were going to get transportation....Our picket replied that he thought the trains would be kept up by pack-mules. This ended the conversation....The above is from a statement made me by Private Collins, Eighth Regulars, one of my own men on duty....Very respectfully, your obedient servant, M. R. PATRICK, Provost-Marshal. General.