THE FIRST DAY
Informed by Pettigrew that Union forces had reached Gettysburg, and anxious to know their strength, Hill sent Heth’s and Pender’s Divisions with Pegram’s battalion of artillery forward on a reconnaissance in force. This movement, made at 5.30 A.M. on July 1, precipitated the battle.
The advance was soon interrupted by Buford’s skirmishers. On reaching Herr Ridge, which crosses the Cashtown Road at right angles, Hill deployed his line of battle—Heth on both sides of the road with Pender in reserve. Pegram posted his artillery on Herr Ridge, and at 8 o’clock fired his first shot. Buford’s artillery, under Calef, posted on the opposite ridge, fired in reply. The battle was on, and the gravity of the situation was clear to Buford, who at 10.10 A.M. sent this message to Meade:
“The enemy’s force are advancing on me at this point and driving my pickets and skirmishers very rapidly. There is a large force at Heidlersburg that is driving my pickets at that point from that direction. I am sure that the whole of A. P. Hill’s force is advancing.”