President Lincoln quaintly hinted his disbelief in the popular rumors of Grant's intemperance, when, after the battle of Shiloh, he said, "I wish all our generals would drink Grant's whiskey." Before Vicksburg Grant stood alone. The government and the people were more than doubtful of the result. McClernand, Hunter, Fremont, and McClellan were mentioned as his successors. Senators and representatives urged Grant's removal, and one of his corps commanders was plotting for his place. Still he was struggling for success, while friends wavered, and enemies cried out against him. To his heavy load of cares and trials was added this heaviest burden of all--the dread of being removed before he could carry out the great design which had been born in his busy brain. This great design set at nought all the formulæ of the military schools, and was in violation of all the known laws of strategy; but it was not a new idea. Long before canals and operations, in accordance with the recognized rules of warfare, had been discarded as impracticable, he had cherished it as a last resort. The military engineers of the Confederacy were at least the equals, as scientific men, of those of the Union. With every means and material in abundance, they had fortified Vicksburg on the most approved plans, and, aided by the immense natural advantages of the position, had succeeded in building up a "Gibraltar" which could not be captured. To them the issue was no less than the very existence of the Confederacy; for, cut off from its supplies in Texas, its conquest was only a question of time. These engineers made sure that they had not deceived themselves. They piled up defences, and extended their batteries, until Gibraltar and Sevastopol were beggared in their strength in comparison with Vicksburg. Doubtless, measured by the ordinary rules of military security, and by the ability of any force governed by the recognized canons of warfare, the Confederate engineers were fully justified in their perfect confidence. All the communications behind Vicksburg were in their hands. No base of supplies could be established below or in the rear of the stronghold. Impenetrable swamps and morasses defended it above, for they afforded no resting place whereon an army could stand. The fortified heights of Walnut Hills frowned for miles above the submerged lands on the Yazoo. The whole strength of the Rebellion was in the rear of the city, and armies could be rushed in upon a hostile force gathered there, by the railroads. To any other man than Grant it would have been a hopeless task; but he set at nought the rules of war under which Vicksburg was safe.