From the diary of Secretary of the Navy Gideon Welles, July 4, 1863:
I was called up at midnight precisely by a messenger with telegram from Byington, dated at Hanover Station, stating that the most terrific battle of the War was being fought at or near Gettysburg, that he left the field at half-past 6 P.M. with tidings, and that everything looked hopeful. The President was at the War Department, where this dispatch, which is addressed to me, was received. It was the first word of the great conflict. Nothing had come to the War Department. There seems to have been no system, no arrangement, for prompt, constant, and speedy intelligence.…
The information this morning and dispatches from General Meade confirm Byington’s telegram. There is much confusion in the intelligence received. The information is not explicit. A great and bloody battle was fought, and our army has the best of it, but the end is not yet. Everything, however, looks encouraging.
Later in the day dispatches from Haupt and others state that Lee with his army commenced a retreat this A.M. at three o’clock. Our army is waiting for supplies to come up before following, a little of the old lagging infirmity.