Orders had been issued on February 27, to Mr. Tucker, assistant secretary of war, to prepare means of transporting down the Potomac, troops, munitions, artillery, horses, wagons, food, and all the vast paraphernalia of a large army. He showed a masterly vigor in this difficult task, and by March 17 the embarkation began. On April 2 McClellan arrived at Fortress Monroe. On the very next day he was disturbed by the revocation of the orders which had left him in command of that place and had allowed him to "draw from the troops under General Wool a division of about 10,000 men, which was to be assigned to the First Corps." Another and a serious disappointment also occurred at once; he found that the navy could not be utilized for assisting in an attack on Yorktown, or for running by it so as to land forces in rear of it. He must therefore depend wholly upon his army to force a way up the Peninsula. This he had stated to be an unsatisfactory alternative, because it involved delay at Yorktown. Nevertheless, having no choice, he began his advance on April 4. He had with him only 58,000 men; but more were on the way, and McDowell's corps was to be brought forward to join him as rapidly as transportation would permit. His total nominal force was smaller than the minimum which, on February 3, he had named as necessary; yet it was a fine body of troops, and he had lately said to them: "The army of the Potomac is now a real army, magnificent in material, admirable in discipline, excellently equipped and armed. Your commanders are all that I could wish."