About 10 o'clock
`` By 9 o'clock an occasional shot could be heard , and then the rattle of musketry , as though a company or so had discharged their pieces . Presently a few skirmishers would come back to the main line , asserting that the enemy were in force in our front . Then orders would be given to advance the skirmish-line and feel for the enemy . `` About 10 o'clock a shot from the artillery of the enemy announced the fact that he was posting for resistance . Our line at once advanced as best it could in the direction of the enemy . The musketry opened and continued to increase until one whole division of our troops were engaged . The artillery opened on both sides and roared as the mighty thunders .