Hooker left the Army of the Cumberland in consequence of having freely criticised Sherman's movements on the advance on Atlanta. The failure of Sherman to promptly follow up his success in seizing Snake Creek Gap, and to retrieve the blunder of McPherson on retiring from before Resaca in May, 1864, was particularly provoking not only to Hooker, but to every other commander who saw Joe Johnston slip through Sherman's fingers in consequence of that delay, and Hooker very freely alluded to it as a blunder. The natural consequence of this, and subsequent instances of candid criticism on Hooker's part, was the creation of some considerable prejudice against him in Sherman's mind. Sherman was of too bilious a temperament ever to sacrifice an opportunity to vent his spleen, and when he found an occasion he took care to resent the insult of which Hooker had been guilty in criticising him, forgetting that Curtius and Alexander, Jomini and Napoleon had ever existed. The opportunity came. When McPherson, the commander of the Army of the Tennessee, was killed in front of Atlanta, Hooker was left the senior major general in command of a corps in Sherman's department, and he naturally expected to be placed in command, the more so as the President so desired. But Sherman appointed General O. O. Howard to the command, subject, of course, to the approval of the commander-in-chief. Mr. Lincoln telegraphed Sherman, requesting him to appoint General Hooker; and on Sherman's reiteration of his desire to have General Howard appointed, the President urged Hooker's appointment in stronger terms. General Sherman was determined that Hooker should not be appointed, and with an impertinence characteristic of Sherman, replied, that "his resignation was at the service of the President." Had Mr. Lincoln been a thorough military man instead of a good-natured and indulgent President, he would have at least punished Sherman for such an unwarrantable reply, but he only smiled at it and liked Sherman, as every body else did, all the better for what looked like independence rather than impertinence. The consequence was that Howard was appointed. A thousand worse appointments might have been made, and I don't know but what the methodical Howard better suited the command than Hooker would have done. Hooker took umbrage at the appointment of Howard--the insult was too glaring and offensive to be overlooked--and at his own request he was relieved of command under Sherman by the President, and given the command of the Department of the North.