Because vision was limited at 4:00 a.m., the Union attack began at 4:40 a.m. with the firing of a signal gun from Fort Fisher. The 1st Vermont Brigade, with Colonel Amasa Tracy commanding in lieu of the wounded Lewis Grant, led the assault. Pioneers were in front to dismantle abatis and other obstructions. Artillerymen were also placed with the attackers to turn captured Confederate guns against them. An artillery battery of four guns was assigned to each division with two others in reserve while three others were left in the Union forts. Sharpshooters also were deployed with the attackers. The heavy bombardment already launched along the IX Corps' front masked the sound of the signal gun from Fort Fisher for some of the officers. A staff officer had to hail Colonel Tracy of the Vermont Brigade to begin the attack. The attack started in such dim light that the men still could not see much beyond the extent of their own company.