At Falmouth Colonel Spaulding learned that the train sent by water had been taken to general headquarters on the morning of the 24th. From that date the trains were at all times available for crossing the Rappahanock at short notice, but they were not actually used until the morning of December 11.

Numbers 6. Report of Captain Samuel T. Cushing, Second U. S. Infantry, Acting Chief Signal Officer.

CAMP NEAR FALMOUTH, VA., December 21, 1862.

COLONEL: I have the honor to submit the following report of duties performed by the acting signal corps, Army of the Potomac, during the operations before Fredericksburg, commencing December 11 and ending December 16, 1862:

The crossing of the river was to be effected under the cover of our batteries, stationed on the hills on this side of the river. It was desirable to place these batteries in communication with the troops, when crossing with general headquarters, and with each other. With this object in view, the station at the Phillips house (General Sumner's headquarters) was continued in operation, and other stations communicating to it were established-one upon a hill near Falmouth and near Colonel Hays' headquarters; one upon the Corn Bluff, southeast of the Phillips house, and near Colonel Tyler's headquarters, and another at the Lacy house, near Colonel Tompkins' headquarters. These stations were directed to observe narrowly the country upon the other side of the river, and to report to the general commanding, and to the officers commanding in the vicinity, the position of all troops and such other items of interest as might come within the range of vision. A station of observation was also established south of the Corn Bluff, and near the batteries under the command of Captain De Russy; to report to him and to the headquarters station the results of their observations, and to open communication with the left wing as soon as it should cross the river. Officers were also sent to each of the principal bridges, with instructions to cross with the advance guards of each grand division, and to select suitable positions from which to communicate with the stations previously enumerated upon the hills on this side.

On the 5th instant, three officers had been sent with their flagmen and necessary equipments to the gunboats, then lying near Port Conway, to enable them, if occasion required, to co-operate with the land forces in any crossing or other movement in which they might be employed.

The above was the general plan of the duties assigned to the officers upon these days.

At daylight on the morning of December 11, the officers were stationed at the different points to which they had been ordered. A heavy mist having arisen during the night, prevented any communication being opened before 12 m., when it raised sufficiently to admit of signaling to the headquarters station at the Phillips house, worked by Lieuts. James S. Hall and P. A. Taylor, from Lieuts. F. Wilson and R. Dinsmore, at the Lacy house, and Lieuts. James A. Hebrew and William T. Barrett, at the Corn Bluff.

About 5 p.m. a portion of General Franklin's troops crossed the river.