_June 17._--After a refreshing night's rest, we were up early in the morning, and resumed our march at six o'clock, taking the Warrenton Turnpike. Kilpatrick has the advance of the corps. We soon crossed the memorable fields of the two Bull Run battles, passed the famous field of Groveton, and there deflecting to the right, and pushing forward rapidly, we arrived by noon in sight of the hills which partially surround the village of Aldie, on the north side of the Bull Run Mountains. Kilpatrick had been directed to move through Aldie, and thence to and through Ashby's Gap, in the Blue Ridge, learn all he could of the enemy's movements, and, then returning, to rejoin the corps at Nolan's Ferry on the Potomac. Colonel Duffie, with his regiment, the First Rhode Island, was ordered to move through Thoroughfare Gap, and to join Kilpatrick in Pleasant Valley beyond. These plans were laid with the presumption that no very heavy force of Rebels remained north of the Blue Ridge, and none at all north of the Bull Run Mountains. But this was a great mistake. BLOODY BATTLE OF ALDIE. James Moore, M. D., Surgeon of the Ninth Pennsylvania Cavalry, thus describes what occurred to Kilpatrick and his command at this place: "Scarcely had his advance reached the town of Aldie, when it came directly upon the advance-guard of W. H. F. Lee. It was entirely unexpected. No enemy was supposed to be on the Aldie side of the Bull Run Mountains. "The general rode to the front, ran his eye over the field for a moment, and then rapidly gave his orders. He had taken in the whole field at one rapid glance, and saw the important points that must be gained. The Harris Light Cavalry was directed to charge straight down the road, through the town, gain and hold the long, low hill over which runs the road from Middleburg. With anxious eye he watched the charge, on which so much depended, saw that it was successful, and quickly and resolutely pushed in one regiment after another on the right of the Harris Light, till the high hills far on the right of Aldie were gained. "This fine disposition was made, and important position won, before the Rebel General Fitzhugh Lee could make a single effort to prevent it, although he had a division of cavalry at his back. "He soon recovered, however, from the temporary surprise, and for two hours made most desperate efforts to regain the position lost. He struck the right, left, and centre in quick succession, while his battery of Blakely guns thundered forth their messengers of death. "But all in vain! Kilpatrick's gallant men--the heroes of Brandy Station--met and hurled back each charge, while Randall's battery, ignoring entirely the Rebel guns, sent his canister and shells tearing through the heavy columns of the enemy.