This latter officer was the topographical engineer of the Second Corps of the Army of Northern Virginia, and made his surveys by order of Gen. Lee immediately after the campaign. They are of the greatest assistance and value. Eighteen years have elapsed since North and South crossed swords upon this memorable field; and it would seem that all Americans can now contemplate with unruffled heart the errors under which "the Army of the Potomac was here beaten without ever being fought," as well as boast with equal pride, not only of the abundant courage displayed by either side, but of the calm skill with which Gen. Lee wrested victory from a situation desperately compromised, and of the genius of that greatest of his lieutenants, Thomas J. Jackson, who here sealed with his blood his fidelity to the cause he loved so well. It has been said that this campaign furnishes as much material for the psychological as for the military student. And certainly nothing less than a careful analysis of Hooker's character can explain the abnormal condition into which his mental and physical energy sank during the second act of this drama. He began with really masterly moves, speedily placing his wary adversary at the saddest disadvantage. But, having attained this height, his power seemed to pass away as from an over-tasked mind. With twice the weight of arm, and as keen a blade, he appeared quite unable to parry a single lunge of Lee's, quite unable to thrust himself. He allowed his corps commanders to be beaten in detail, with no apparent effort to aid them from his abundant resources, the while his opponent was demanding from every man in his command the last ounce of his strength. And he finally retired, dazed and weary, across the river he had so ably and boastingly placed behind him ten days before, against the opinion of nearly all his subordinates; for in this case the conditions were so plain that even an informal council of war advised a fight. With character-study, however, this sketch has nothing to do. It is confined to describing events, and suggesting queries for the curious in military history. II. CONDITION OF THE COMBATANTS.