The losses were heavy on both sides, but the enemy was fairly beaten, and driven from his chosen positions; and night closed the most sanguinary day ever known to the American continent. McClellan ought to have followed up his victory early next morning, but hesitating, the enemy made good his escape across the Potomac, leaving only his dead and desperately wounded, the latter numbering about two thousand, in our hands. _October 4._--We are still in our camps at Hall's Hill, teaching and learning the tactics of war. To-day Kilpatrick detailed me to act as drill-master, and gave me the command of a detachment of recruits. This gives me a new phase of army experience, and though it has its difficulties, as one will always find when he endeavors to control "men of many minds," yet I find a good exercise of my little knowledge of human nature, and realize that the influence of my new labor upon myself is very salutary. I had thought that I was master of all the preliminary steps of the science and art of a soldier's discipline, but in endeavoring to teach the same to others, I have learned so much myself, that it now seems to me that what I knew before was the merest rudiment. This I learn is the experience of others who are engaged in similar work. Helping others has a wonderful reflex influence upon ourselves. I often wonder if this may no explain in part the philosophy of that passage of Holy Writ, which says, "It is more blessed to give than to receive." In this exercise of drilling, and in the comparative monotony of camp life, we spent the month of October. All was quiet along the entire lines of the great armies. Our ranks had been greatly swollen by new accessions; yet General McClellan was constantly calling for reenforcements, and all kinds of supplies, alleging that the army was in no condition to move. At length about the twenty-sixth of October a feeble advance was made across the Potomac. Several days were spent in putting the Federal army on the sacred soil and under marching orders. No opposition was encountered in the march. Our forces moved along the east side of the Blue Ridge, the enemy still occupying the Shenandoah Valley, and moving southward on a line parallel with our own. _November 2._--The Harris Light broke camp at Hall's Hill and advanced to the Chantilly Mansion, bivouacking on its beautiful grounds. This property is said to be owned by one of the Stuarts, who is reported to be a quartermaster-general in the Rebel service. Pleasant as was the place, with its fine walks, bordered with flowers and evergreen shrubbery; its fruitful gardens and groves, the cold of the night made our stay not the most agreeable. The next morning we pursued our line of march to Sudley Church, near Bull Run, where we encountered a strong force of Stuart's cavalry. After a sharp conflict, in which Yankee ingenuity and grit were fairly tested, the chivalry retired southwestwardly, acknowledging themselves badly defeated.