Having tried, he now "determined upon a regular siege--to 'outcamp the enemy,' as it were, and to incur no more losses. The experience of the 22d convinced officers and men that this was best, and they went to work on the defences and approaches with a will."(1) It has also to be remembered, in any fair and candid consideration of the subject, that at this comparatively early period of the war even such bloody lessons as Fredericksburg had not sufficed to teach either the commanders or their followers on either side, Federal or Confederate, the full value, computed in time, of even a simple line of breastworks of low relief, or the cost in blood of any attempt to eliminate this value of time by carrying the works at a rush. Indeed, it may be doubted whether, from the beginning of the war to the end, this reasoning, in spite of all castigations that resulted from disregarding it, was ever fully impressed upon the generals of either army, although at last there came, it is true, a time when, as at Cold Harbor, the men had an opinion of their own, and chose to act upon it. It is also very questionable whether earthworks manned by so much as a line of skirmishers, prepared and determined to defend them, have ever been successfully assaulted save as the result of a surprise. Sedgwick's captures of the Rappanhannock redoubts and of Marye's Heights have indeed been cited as instances to the contrary, yet on closer consideration it is apparent that although in the former case the Confederates had been looking for an attack, they had given up all expectation of being called on to meet it that day, when, just at sunset, Russell fell suddenly upon them and finished the affair handsomely before they had time to recover. Marye's Heights, again, may be described as a moral surprise, for no Confederate officer or man that had witnessed the bloody repulse of Burnside's great army on the very same ground, but a few weeks before, could have expected to be called on so soon to meet the swift and triumphant onset of a single corps of that army. Moreover, Sedgwick's tactical arrangements were perfect.