7. For a given operation, the best strategic line, and the different maneuvers necessary to embrace all possible cases. 8. The eventual bases of operations and the strategic reserves. 9. The marches of armies, considered as maneuvers. 10. The relation between the position of depots and the marches of the army. 11. Fortresses regarded as strategical means, as a refuge for an army, as an obstacle to its progress: the sieges to be made and to be covered. 12. Points for intrenched camps, _tétes de pont,_ &c. 13. The diversions to be made, and the large detachments necessary. These points are principally of importance in the determination of the first steps of a campaign; but there are other operations of a mixed nature, such as passages of streams, retreats, surprises, disembarkations, convoys, winter quarters, the execution of which belongs to tactics, the conception and arrangement to strategy. The maneuvering of an army upon the battle-field, and the different formations of troops for attack, constitute Grand Tactics. Logistics is the art of moving armies. It comprises the order and details of marches and camps, and of quartering and supplying troops; in a word, it is the execution of strategical and tactical enterprises. To repeat. Strategy is the art of making war upon the map, and comprehends the whole theater of operations. Grand Tactics is the art of posting troops upon the battle-field according to the accidents of the ground, of bringing them into action, and the art of fighting upon the ground, in contradistinction to planning upon a map. Its operations may extend over a field of ten or twelve miles in extent. Logistics comprises the means and arrangements which work out the plans of strategy and tactics. Strategy decides where to act; logistics brings the troops to this point; grand tactics decides the manner of execution and the employment of the troops. It is true that many battles have been decided by strategic movements, and have been, indeed, but a succession of them; but this only occurs in the exceptional case of a dispersed army: for the general case of pitched battles the above definition holds good. Grand Tactics, in addition to acts of local execution, relates to the following objects:-- 1. The choice of positions and defensive lines of battle. 2. The offensive in a defensive battle. 3. The different orders of battle, or the grand maneuvers proper for the attack of the enemy's line. 4. The collision of two armies on the march, or unexpected battles. 5. Surprises of armies in the open field. 6. The arrangements for leading troops into battle. 7. The attack of positions and intrenched camps. 8. _Coups de main_. All other operations, such as relate to convoys, foraging-parties, skirmishes of advanced or rear guards, the attack of small posts, and any thing accomplished by a detachment or single division, may be regarded as details of war, and not included in the great operations.