his aid asked by Halleck after Pope's defeat, 80;
kept inactive during Pope's campaign, 81;
appointed by Lincoln, in spite of protests, to command in Washington, 81, 82;
his fitness to reorganize army, 82;
describes steps taken to put him in command, 83;
cautious attitude toward Lee, 84;
at Antietam, 85;
welcomed by troops, 85;
fails to use advantages, 86;
urged by Lincoln to pursue, 86;