But while he spoke thus lightly of his own share in these labors, the confinement, the necessary attention to and study of larger details, even while he intrusted the minor to others, and the unavoidable anxieties of a man who had so many important irons in the fire, and at the same time was approaching his sixty-fourth year, told upon him. To this he bore witness when, after the capture of the Mobile forts, the Department desired him to take command of the North Atlantic fleet, with a view to the reduction of Wilmington, North Carolina. "They must think I am made of iron," he wrote home. "I wrote the Secretary a long letter, telling him that my health was not such as to justify my going to a new station to commence new organizations; that I must have rest for my mind and exercise for my body; that I had been down here within two months of five years, out of six, and recently six months on constant blockade off this port, _and my mind on the stretch all the time_; and now to commence a blockade again on the Atlantic coast! Why, even the routine of duty for a fleet of eighty sail of vessels works us all to death; and but that I have the most industrious fleet-captain and secretary, it would never be half done. It is difficult to keep things straight." "I know," he writes on another occasion, "that few men could have gone through what I have in the last three years, and no one ever will know except yourself perhaps.... What the fight was to my poor brains, neither you nor any one else will ever be able to comprehend. Six months constantly watching day and night for an enemy; to know him to be as brave, as skilful, and as determined as myself; who was pledged to his Government and the South to drive me away and raise the blockade, and free the Mississippi from our rule. While I was equally pledged to my Government that I would capture or destroy the rebel."