The Crimean and Italian wars had foreshadowed the passing away of the old military conditions and the dawning of a new era of warfare. But it was in the gigantic struggle which rocked our own country for four years that the developments of modern warfare really commenced. At the beginning of this great conflict the ranges of 1000 to 1200 yards for field guns, and of 1500 to 2000 yards for heavy guns, were as great as could be secured with any degree of accuracy. The infantry rifle with which the Union and Confederate armies were armed had an extreme range of but 1000 yards, and a really effective range of only half that distance. The rifle was a muzzle-loader, which required nine distinct motions in loading besides those necessary in priming the piece with the percussion cap then used. The tactics employed at first in all arms of the service did not differ materially from the methods employed in the Napoleonic wars; and a line of American infantry deployed for battle in two ranks, shoulder to shoulder, scarcely differed in anything but the color of its uniforms from the “thin red line” of Wellington’s warriors. All this was to be changed; but it was not only in the matter of arms and tactics that a revolution was to be effected, for new forces hitherto untried were to be employed in the art of war. The War of Secession was not only one of the most gigantic conflicts ever waged on earth, but was one which will always be of interest to the military student because of its remarkable developments in the science of warfare, and one which will ever be a source of pride to Americans because of the grim earnestness and stubborn valor displayed by the contending armies. From first to last, more than two millions of men were enrolled by the United States, and in the final campaign 1,100,000 men were actually bearing arms in the service of the Union. The infantry was organized in companies of one hundred men, ten companies forming a regiment. At first, three or four regiments constituted a brigade, though it was afterwards formed of a greater number when the regiments became depleted by the losses of battle. Three brigades generally composed a division, which also habitually included two batteries of artillery and a small detachment of cavalry for duty as orderlies and messengers. Three or more divisions constituted an army corps. The cavalry was formed into brigades and divisions, which in the later years of the war were combined to form, in each of the large armies, a corps of cavalry. It was in command of such corps of mounted troops that Sheridan, J. E. B. Stuart, Merritt, and Wilson achieved their great fame. The batteries first distributed to divisions, or even brigades, were afterwards assigned to the army corps, and all guns not thus employed were grouped into a corps of reserve artillery.