The force engaged at Gaines' Mill was: Union, 50 Regiments, 20 batteries, 27,000 men. Confederate: 129 Regiments, 19 batteries, 65,000 men. Losses: Union, killed, 894; wounded, 3,107; missing, 2,836; total, 6,837. Confederate: Somewhat larger, especially in killed and wounded. Perhaps in the whole history of the war there was no battle fought with more desperation on both sides than that of Mechanicville (June 26), and Gaines' Mill (June 27). Fitz John Porter handled his army with such ability that his inferior force repelled repeated attacks of the flower of the rebel army under Lee and Jackson; and if it were not for the blundering of the cavalry, under Gen. Cook, through whose instrumentality Porter's lines were broken, he would have repelled all efforts to drive him to the river. As an evidence of the desperate nature of the conflict, it may be mentioned that one Rebel regiment (Forty-Fourth Georgia) lost three hundred and thirty-five men. We got there, about eight miles, at eight o'clock, having pushed on by forced marches all the way, but too late to change the fortunes of the day. We did check the advancing and exalting Rebels, who supposed a large part of the Union army had come to the rescue. Forming our lines on top of the hill (Gain's) with an Irish cheer we went down the northern side of the hill pell-mell for the enemy. The pursuers were now the pursued. The Rebels broke and fled before Irish steel. To advance in the darkness would be madness. The regiments were brought to a halt. So as to deceive the Confederates as to the number of reinforcements, the position of each regiment was constantly changed. In one of these movements, the right of the Sixty-Third struck a rebel battalion, halted in the darkness, and for a time there was temporary confusion. The grey coats were brushed aside instantly, getting a volley from the right wing of the Sixty-Third as a reminder that we meant business. Fitz John Porter pays this tribute to the brigade as to the part it took on this occasion: "French and Meagher's brigades of Sumner's corps, all that the corps commanders deemed they could part with, were sent forward by the commanding general.... All soon rallied in rear of the Adams House behind Sykes and the brigades of French and Meagher sent to our aid, and who now with hearty cheers greeted our battalions as they retired and reformed." While resting on our arms the dead and wounded were thick all around--friend and foe. Alas! not a few were our brothers of the Ninth Massachusetts. They told us in whispers how they repelled the enemy all day, and not until they were flanked by the Rebels did they give way before their repeated charges. The remnant of the regiment I subsequently saw next morning, in the rear, few in numbers, but with its spirit unbroken.