The Union General's information as to Beauregard's position and army was accurate and full. He knew that Johnston's command of ten thousand men had begun to arrive the day before. He did not know that half of them were still tangled up somewhere on the railroad waiting for transportation. Even with Johnston's entire command on the ground his army outnumbered the Southerners and his divisions of seasoned veterans from the old army and his matchless artillery gave him an enormous advantage. With consummate skill he planned the battle and began its successful execution. His scouts had informed him that the Southern line was weak on its left wing resting on the Stone Bridge across the river. Here the long drawn line of Beauregard's army thinned to a single regiment supported at some distance by a battalion. Here the skillful Union General determined to strike. At two-thirty before daylight his dense lines of enthusiastic men swung into the dusty moonlit road for their movement to flank the Confederate left. Swiftly and silently the flower of McDowell's army, eighteen thousand picked men, moved under the cover of the night to their chosen crossing at Sudley's Ford, two miles beyond the farthest gray picket of Beauregard's left. Tyler's division was halted at the Stone Bridge on which the lone regiment of Col. Evans lay beyond the stream. He was ordered to feign an attack on that point while the second and third divisions should creep cautiously along a circuitous road two miles above, cross unopposed and slip into the rear of Beauregard's long-drawn left wing, roll it up in a mighty scroll of flame, join Tyler's division as it should sweep across the Stone Bridge and together the three divisions in one solid mass could crush the ten-mile battle line into hopeless confusion. The plan was skillfully and daringly conceived. Tyler's division halted at the Stone Bridge and silently formed as the first glow of dawn tinged the eastern hills. The dull red of the July sun was just coloring the sky with its flame when the second and third divisions crossed Bull Run at Sudley's Ford and began their swift descent upon the rear of the unsuspecting Southern army. As the sun burst above the hills, a circle of white smoke suddenly curled away from a cannon's mouth above the Stone Bridge and slowly rose in the still, clear morning air. Its sullen roar echoed over the valley. The gray figures on the hill beyond leaped to their feet and looked. Only the artillery was engaged and their shots were falling short.