NOTE.—See Chapter XVII., where the Battle of Brandywine, through the disorder of Sullivan’s Division, unaccustomed to act as a Division, or as a part of a consolidated Grand Division or Corps, exactly fulfilled the conditions which made the first Battle of Bull Run disastrous to the American Federal Army in 1861. Subsequent _skeleton drills_ below Arlington Heights, were designed to quicken the proficiency of fresh troops, in the alignments, wheelings, and turns, so indispensable to concert in action upon an extensive scale. In 1898 the fresh troops were largely from militia organizations which had been trained in regimental movements. School battalions and the military exercises of many benevolent societies had also been conducive to readiness for tactical instruction. The large Camps of Instruction were also indispensably needed. Here again, time was an exacting master of the situation. III. LOGISTICS.—The practical art of bringing armies, fully equipped, to the battlefield. NOTE.—In America where the standing army has been of only nominal strength, although well officered; and where militia are the main reliance in time of war; and where varied State systems rival those of Washington’s painful experience, the principle of Logistics, with its departments of transportation and infinite varieties of supply, is vital to wholesome and economic success. The war with Spain which commenced April 21, 1898, illustrated this principle to an extent never before realized in the world’s history. Familiarity with details, on so vast a scale of physical and financial activity, was impossible, even if every officer of the regular army had been assigned to executive duty. The education and versatile capacity of the American citizen had to be utilized. Their experience furnished object lessons for all future time. IV. ENGINEERING.—The application of mathematics and mechanics to the maintenance or reduction of fortified places; the interposition or removal of artificial obstructions to the passage of an army; and the erection of suitable works for the defence of territory or troops. NOTE.—The invention and development of machinery and the marvellous range of mechanical art, through chemical, electrical, and other superhuman agencies, afforded the American Government an immediate opportunity to supplement its Engineer Corps in 1898, with skilled auxiliaries. In fact, the structure of American society and the trend of American thought and enterprise, invariably demand the best results. What is mechanically necessary, will be invented, if not at hand. That is good engineering. V. MINOR TACTICS.—The instruction of the soldier, individually and _en masse_, in the details of military drill, the use of his weapon, and the perfection of discipline.