Now that the stirring events of those days are history it may be interesting to notice as we go along the rapid evolution of the drama of Gettysburg, which we, so lately menaced in our stronghold at Fort Washington, little dreamed was being consummated with such tremendous suddenness. It was so lately as the Sunday just passed that we were kept under arms all day expecting an assault from Ewell, who was known to be threatening Harrisburg with the greatest part of his corps. On Monday the reconnoissance had developed the presence of the enemy still investing our position. But on the night of Monday, 29th, Lee first learned with surprise of the dangerous proximity of Gen. Hooker, threatening his communications, and resolved to concentrate his now somewhat scattered army eastward of the South Mountains. Accordingly Ewell must have moved off from our front the same night, or early on Tuesday morning, since he re-appears upon the scene on Wednesday afternoon at Gettysburg, where he arrived between one and two o'clock, P.M.--just in time to check, with the aid of other reinforcements, the advance of General Reynolds and to drive him back with heavy loss. These reinforcements must all have made forced marches and they could have been in no condition to follow up the advantage gained. Lee was doubtless well content to have turned back, with his fatigued battalions, the rising tide of victory, and _nolens volens_, left General Howard, who succeeded to the command of the field on the fall of the lamented Reynolds, at liberty to establish himself unmolested on the now famous cemetery heights. It is interesting and instructive to notice further, that this corps of Ewell, whose reported withdrawal from the investment of Fort Washington was apparently the signal for our advance, reached Gettysburg, and was there instrumental in snatching victory from the jaws of defeat, absolutely before our movement began! _Thursday, July 2d._--At 3 A.M., we are aroused from sleep by a whispered summons to get ready to move at once without making the least noise! This looks like work. The reflection of the fire in front has disappeared, the cannonading is hushed, and all is still. What does it mean? A report comes flying through the field that the enemy have driven back our advance and that these are falling back upon our lines.