e after midnight of July 17th, he received orders from the Confederate authorities to go at once to the help of Beauregard.
Just twenty-four hours had elapsed since Patterson's order to retreat, and the Union army was already at Charlestown.
By nine o'clock on the morning of July 18th, Johnston's scouts brought him reports indicating clearly the actual situation.
At noon of that day he had his whole effective force of nine thousand men on the march; at nightfall his advance passed through Ashby's Gap of the Blue Ridge; by eight o'clock on the 19th it was at Piedmont, the nearest station of the Manassas Gap Railroad, and embarking here in cars, seven regiments were in Beauregard's camp, at Manassas, that afternoon.
Johnston himself, with another detachment, arrived at Manassas at noon of Saturday, July 20th; and most of the remainder of his force reached the battle-field of Bull Run in the nick of time to take a decisive part in that famous conflict, about three o'clock on Sunday,