"The rapid firing of Sheridan's attack" is good. Sheridan is entitled to the credit of placing Custer where he was. But that is all. Sheridan was not on the ground to direct the attack in any way; nor was the division commander on the ground. It was Custer's attack and it was Custer's victory. The only dismounted cavalry that attacked Barlow was Rosser's cavalry, and Custer's cavalry was between Rosser and Barlow. The only artillery with which the dismounted cavalry opened on Barlow was Rosser's battery and Custer and his men were between Barlow and that battery. Had Barlow taken the trouble to ascertain what was really going on in his front, an easy matter, he would have found that, so far from this dismounted cavalry endangering his flank, they had been driven off the field in headlong flight, leaving their dead and wounded. There was never a moment during the entire day (May 6, 1864,) when Barlow was in the slightest danger of being flanked. His failure to advance, enabled Longstreet to swing across his front and attack Birney's left, thus neutralizing Hancock's victory over Hill. If Barlow and Gibbon had advanced as they were ordered to do, they would have struck Longstreet's flank and, probably, crushed it.
All of which seems to demonstrate that, in battle, as in the ordinary affairs of life, imaginary dangers often trouble us more than those which are real.
The fear of being flanked was an ever present terror to the army of the Potomac, and the apparition which appeared to McDowell at Manassas, to Pope at the Second Bull Run, to Hooker at Chancellorsville, flitted over the Wilderness also, and was the principal cause why that campaign was not successful.
And then again, General Meade placed too low an estimate upon the value of cavalry as a factor in battle and failed utterly to appreciate the importance of the presence of Sheridan's troopers upon his left. Had Meade and Hancock known Sheridan then, as they knew him a year later, when he intercepted the flight of the army of Northern Virginia at Five Forks and Sailor's Creek, there would have been in their minds no nervous apprehension that Longstreet might reenact in the Wilderness the part played at Chancellorsville by Stonewall Jackson. As it was, Grant's strategy and Hancock's heroism were paralyzed by these false rumors about Longstreet's menacing the safety of the Potomac army by moving against its left and rear. If such a thing was seriously intended, it was met and thwarted by Custer and Gregg who, alone and unaided as at Gettysburg, successfully resisted every effort on the part of Stuart's cavalry to break through the union lines. The noise of the successful battle which the union cavalry was waging, instead of reassuring the federal commanders as it should have done, served only to increase the alarm which extended to General Hancock and to army headquarters, as well. If a proper rating had been placed upon the services of the cavalry all apprehension would have been quieted. Barlow and Gibbon would have moved promptly to the front as directed, and Hill and Ewell might have been crushed before Longstreet was in position to save them.