FIRST practical machine gun. FIRST repeating rifle used in combat. FIRST use of the railroads as a major means of transporting troops and supplies. FIRST mobile siege artillery mounted on rail cars. FIRST extensive use of trenches and field fortifications. FIRST large-scale use of land mines, known as "subterranean shells". FIRST naval mines or "torpedoes". FIRST ironclad ships engaged in combat. FIRST multi-manned submarine. FIRST organized and systematic care of the wounded on the battlefield. FIRST widespread use of rails for hospital trains. FIRST organized military signal service. FIRST visual signaling by flag and torch during combat. FIRST use of portable telegraph units on the battlefield. FIRST military reconnaissance from a manned balloon. FIRST draft in the United States. FIRST organized use of Negro troops in combat. FIRST voting in the field for a national election by servicemen. FIRST income tax--levied to finance the war. FIRST photograph taken in combat. FIRST Medal of Honor awarded an American soldier. BROTHER AGAINST BROTHER "_And why should we not accord them equal honor, for they were both Americans, imbued with those qualities which have made this country great._" _--BELL IRVIN WILEY_ PRESIDENT LINCOLN, the Commander-In-Chief of the Union Army, had four brothers-in-law in the Confederate Army, and three of his sisters-in-law were married to Confederate officers. JEFFERSON DAVIS, Commander-in-Chief of the Confederate Army, served the U.S. Army as a colonel during the Mexican War and held the post of Secretary of War in President Pierce's cabinet. Previously, as a senior United States Senator, he had been Chairman of the Senate Military Affairs Committee. Lincoln and Davis were born in Kentucky, the only state that has ever had two of its sons serve as President at the same time. JOHN TYLER, 10th President of the United States, was elected to the Confederate States Congress in 1862, but died before it convened. On March 4, 1861, Tyler's granddaughter unfurled the first flag of the Confederacy when it was raised over the Confederate Capitol at Montgomery, Alabama. The Battle of Lynchburg, Virginia, in June 1864 brought together two future Presidents of the United States--General RUTHERFORD B. HAYES and Major WILLIAM McKINLEY, U.S.A.--and a former Vice-President--General JOHN C. BRECKINRIDGE, C.S.A. Five other Union generals later rose to the Presidency: ANDREW JOHNSON, U.S. GRANT, JAMES A. GARFIELD, CHESTER A. ARTHUR, and BENJAMIN HARRISON. The four Secretaries of War during the eleven years prior to the Civil War were all from the South. All four later held office in the Confederate government.