It took Tom two days to get from Harrisburg to Cairo, the southernmost town in Illinois. It lies at the junction of the Mississippi and Ohio rivers. The latter pours a mass of beautiful blue water--the early French explorers named the Ohio "the beautiful river"--into the muddy flood of the Mississippi. For miles below Cairo the blue and yellow streams seem to flow side by side. Then the yellow swallows the blue and the mighty Mississippi rolls its murky way to the Gulf of Mexico. A gunboat took the young messenger from Cairo to General Grant's headquarters. [Illustration: MISSISSIPPI RIVER GUNBOATS] A Western gunboat was an odd thing. James B. Eads, an eminent engineer, who after the war built the St. Louis bridge and the New Orleans jetties, which keep the mouth of the Mississippi open, had launched a flotilla of gunboats for the government within four months of the time when the trees which went to their making were growing in the forests. On a flat-boat of the ordinary Western-river type, Mr. Eads put a long cabin, framed of stout timbers, cut portholes in the sides, front and rear of it, mounted cannon inside it, covered it with rails outside (later armor-plate was used), and behold, a gunboat. The one which sped swiftly with Tom down the Mississippi and waddled slowly with him up the Tennessee, against the current of the Spring freshets, finally landed him at Grant's headquarters. Tom approached the tent over which headquarters' flag was flying with a beating heart. It beat against the long envelope that lay in the inner pocket of his waistcoat. He was about to finish his task and he was about to see the one successful soldier of the Union, up to that time. The Northern armies had not done well in the East--the defeat had been disgraceful and the panic sickening with the raw troops at Bull Run, Virginia, and little had been gained elsewhere--but in the West Grant was hammering out success. All eyes turned to him. * * * * * Upon the top of a low knoll, half a dozen packing-boxes were grouped in front of the tent. Two or three officers, most of them spick and span, sat upon each box except one. Upon that one there lounged a man, thick-set, bearded, his faded blue trousers thrust into the tops of dusty boots, his blue flannel shirt open at the throat, his worn blue coat carrying on each shoulder the single star of a brigadier-general. It was General Grant, Hiram Ulysses Grant, now known as U. S. Grant. When the Confederate commander of Fort Donelson had asked him for terms of surrender, he had answered practically in two words: "unconditional surrender." The curt phrase caught the public fancy, and gave his initials a new meaning. He was long known as "Unconditional Surrender" Grant.