On the twenty-first of June Pemberton planned an escape across the Mississippi and built some rough boats. But Grant heard of this; the flotilla grew more watchful still; and before any attempt at escape could be made the great mine was fired on the twenty-fifth. The whole top of the hill was blown off, and with it some men who came down alive on the Federal side. Among these was an unwounded but terrified colored man, who, on being asked how high he had gone, said, "Dunno, Massa, but t'ink 'bout t'ree mile." An immense crater was formed. But there was no practicable breach; so the assault was deferred. A second mine was exploded on the first of July. But again there was no assault; for Grant had decided to wait till several huge mines could be exploded simultaneously. In the meantime an intercepted dispatch warned him that Johnston would try to help Pemberton to cut his way out. But by the time the second mine was exploded Pemberton was sounding his generals about the chances of getting their own thirty thousand to join Johnston's thirty thousand against Grant's seventy-five thousand. The generals said No. Negotiations then began. On the third of July Grant met Pemberton under the "Vicksburg Oak," which, though quite a small tree, furnished souvenir-hunters with many cords of sacred wood in after years. Grant very wisely allowed surrender on parole, which somewhat depleted Confederate ranks in the future by the number of men who, returning to their homes, afterwards refused to come back when the exchange of prisoners would have permitted them to do so. That was a great week of Federal victory--the week including the third, fourth, and eighth of July. On the third Lee was defeated at Gettysburg. On the now doubly "Glorious Fourth" Vicksburg surrendered and the last Confederate attack was repulsed at Helena in Arkansas. On the eighth Port Hudson surrendered. With this the whole Mississippi fell into Federal hands for good. On the first of August Farragut left New Orleans for New York in the battle-scarred _Hartford_ after turning over the Mississippi command to Porter's separate care. Meanwhile the Confederates in Tennessee, weakened by reinforcing Johnston against Grant, had been obliged to retire on Chattanooga. To cover this retirement and make what diversion he could, Bragg sent John H. Morgan with twenty-five hundred cavalry to raid Kentucky, Indiana, and Ohio. Perplexing the outnumbering Federals by his daring, "Our Jack Morgan" crossed the Ohio at Brandenburg, rode northeast through Indiana, wheeled south at Hamilton, Ohio, rode through the suburbs of Cincinnati, reached Buffington Island on the border of West Virginia, and then, hotly pursued by ever-increasing forces, made northeast toward Pennsylvania. On the twenty-sixth of July he surrendered near New Lisbon with less than four hundred men left.