On Thursday, July 18th, Tyler, commanding the first division, moved warily on Centreville, only to find that the Confederates stationed there showed no disposition to fight, but that they fell rapidly back towards Bull Run. This being so, on towards Bull Run Tyler continued his march, his orders being to carefully observe roads, positions, and lay of the land, but under no circumstances to engage in battle. He was to scout, to gather information for future use. But Tyler’s enthusiasm got the better of his discretion, and, it is feared, caused him to forget his orders. He had seen the Confederates retreat before him from Centreville, as though fearing to fight, and then a temptation was thrown in his way in the shape of a favourable position for a battery from which a few shells could be dropped on the enemy. He planted a battery, and fired on a Confederate battery still on the Centreville side of Bull Run. The Southerners retired to Blackburn’s Ford, and Tyler threw forward skirmishers against the Confederate skirmishers, and these getting into a hot exchange, Tyler was soon forced to bring forward a brigade, and then a second; and almost before he knew what was happening he found his battery and his men in a trap. Before he managed to bring away his battery and withdraw his men, he lost close upon a hundred killed, and his soldiers retired in confusion, the officers chagrined over the first serious check of the war. But disastrous as was this the first skirmish of Bull Run to the Northern cause, it on the other hand exposed to General McDowell the position of the Confederates, and showed to him the hopelessness of an attack in front. McDowell’s first plan of battle, perfected at Washington, was to make a vigorous attack on Beauregard’s front, and when this action raged, to cross Bull Run lower down, and while the Confederates were concerned about the safety of their van to fall unexpectedly upon Beauregard’s right and turn it. A personal reconnaissance, made at the moment of Tyler’s unfortunate experiment, proved to McDowell that this plan could not be carried out. The ground on Beauregard’s right was totally unsuited to the job. High hills, densely wooded and strongly held, rendered the scheme clearly unfeasible. Some other plan must be devised. He rode to Centreville with all speed, and there Tyler and his officers reported rifle-its and strong barricades, natural and artificial, in front of every ford, the one bridge spanning the stream strongly guarded and prepared for blowing up if need be, and not the slightest chance of his untrained soldiers carrying the position. These reports convinced McDowell that only a demonstration must be made in front, and his whole energies applied to reaching the southern side of Bull Run, and fighting the battle across fields instead of across deep water. Richardson’s brigade was ordered forward to continue the menace at Blackburn’s Ford, and