ACROSS THE IMPERISHABLE CANVAS of the American Civil Il.. War are vividly recorded feats of arms and armies, and acts of courage and steadfast devotion which have since become a treasured heritage for all Americans. Among the military campaigns, few, if any, present action over so vast an area, of such singular diversity, and so consequential to the outcome of the war, as the great struggle for control of the Mississippi River. Seagoing men-of-war and ironclad gunboats engaged shore defenses and escorted troops along river and bayou; cavalry raids struck far behind enemy lines as the armies of the West marched and countermarched in a gigantic operation which culminated in the campaign and siege of Vicksburg. Protected by heavy artillery batteries on the riverfront and with land approaches to the north and south guarded by densely wooded swamplands, Vicks-kurg defied large-scale land and river expeditions for over a year. Finally the tenacious Grant, in a campaign since accepted as a model of bold strategy and skillful execution, forced the surrender of Vicks-burg on July 4, 1863, splitting the Confederacy in two and securing for the North its great objective in the Western Theater. VICKSBURG AND THE MISSISSIPPI. Control of the Mississippi River, whose course meandered over 1,000 miles from Cairo, Ill., to the Gulf of Mexico and divided the Confederacy into almost equal parts, was of inestimable importance to the Union from the outbreak of hostilities. The agricultural and industrial products of the Northwest, denied their natural outlet to markets down the great commercial artery to New Orleans, would be afforded uninterrupted passage. It would provide a safe avenue for the transportation of troops and their supplies through a tremendous area ill-provided with roads and railroads; the numerous navigable streams tributary to the Mississippi would offer ready routes of invasion into the heart of the South. Union control would cut off arid isolate the section of the Confederacy lying west of