es Bull Run stream; while the strong
divisions under Hunter and Heintzelman--forming McDowell's Right Wing
--are to follow Tyler's Division Westward down the turnpike to a point
within one mile and a half of the Stone Bridge, thence, by cross-road,
diverge several miles to the North, then sweep around gradually to the
West, and then Southwardly over Bull Run at Sudley Springs Ford,
swooping down the Sudley road upon the Enemy's left flank and rear, near
Stone Bridge, rolling it back toward his center, while Tyler's remaining
three brigades cross the bridge and join in the assault. That is the
whole plan in a nutshell.

It has been McDowell's intention to push forward, from Centreville along
the Warrenton Pike a few miles, on the evening of this Military
conference; but he makes his first mistake, in allowing himself to be
dissuaded from that, by those, who, in his own words, "have the greatest
distance to go," and who prefer "starting early in the morning and
making but one move."

The attacking divisions now have orders to march at 2:30 A. M., in order
"to avoid the heat," which is excessive. Tyler's three immediate
brigades--or some of them--are slow in starting Westward, along the
Warrenton Pike, to the Stone Bridge; and this leads to a two or three
hours delay of the divisions of Hunter and Heintzelman, before they can
follow that Pike beyond Centreville, and commence the secret detour to
their right, along the cross-road leading to Sudley Springs.

At 6:30 A.M., Tyler's Artillery gets into position, to cannonade the
Enemy's batteries, on the West Bank of Bull Run, commanding the Stone
Bridge, and opens fire. Half an hour before this, (at 6 A.M.), the
Rebel artillerists, posted on a hill South of the Pike, and 600 yards
West of the bridge, have caught sight of Tyler's Union blue-jackets.
Those of the Rebel gunners whose eyes are directed to the North-East,
soon see, nearly a mile away, up the gradual slope, a puff of blue
smoke. Immediately the bang of a solitary rifle cannon is heard, and
the scream of a rifled shot as it passes over their heads. At
intervals, until past 9 A.M., that piece and others in the same
position, keep hammering away at the Rebel left, under Evans, at Stone
Bridge.

The Rebel response to this cannonade, is very feeble. McDowell observes
this. He suspects there has been a weakening of the Enemy's force at
the bridge, in order to strengthen his right for some purpose. And what
ca