two o'clock
The Confederates were being slowly overwhelmed . The combined Union divisions now consisted of an enveloping battle line of twenty thousand infantry , seven companies of cavalry and twenty-four pieces of artillery , while behind them yet hung ten thousand reserves eager to rush into action . Beauregard 's combined forces defending the hill were scarcely seven thousand men . At two o'clock the desperate Southern commander succeeded in bringing up additional regiments from his right wing . Two brigades at last were thrown into the storm center and a shout rose from the hard-pressed Confederates . Again they charged , drove the Union hosts back and captured a battery of artillery . The hill was saved and the enemy driven across the turnpike into the woods .