[1] In 1866 the first army was composed of divisions not combined into army corps. The second army was worked by army corps. CHAPTER IV PRELIMINARIES OF A CAMPAIGN The movements of an army during a campaign after the first serious engagements can rarely, if ever, be settled in detail before the war. They must needs depend largely on those of the enemy, which cannot be accurately foreseen. But before war is declared, before the fighting begins, while the troops are still in their own territory, a well-conducted government can make its preparations without hindrance. The army can be placed on a war footing, and assembled at whatever point or points are judged most advantageous. These preparations in Prussia fall in different degrees within the domain of the general staff. The changes by which the army is placed on a war footing, known collectively as mobilization, include the calling out of the reserves of men and horses; their distribution among the various corps and their equipment; and the creation and completion of the staffs and of the different services of supply. All these proceedings in Prussia the general staff had perfectly arranged and regulated down to the minutest detail, so that the order needed only to be issued, and the whole operation would take place as if by clockwork within a given number of days.[1] The process of mobilization is in essentials the same whatever be the frontier on which the war is to be fought. It places the troops ready at their ordinary headquarters, and in Prussia no regiment leaves its headquarters except in perfect readiness to take the field. On the other hand, the collection of the army on the frontier is the first stage of the actual operations, resembling the opening of a game of chess, and it is of the greatest importance that the points selected should be those best suited for the beginning of the particular campaign in prospect. The placing of an army on a war footing and its transport to a frontier are political acts of the gravest moment. They are therefore usually controlled almost as much by political as by military considerations, and it is impossible rightly to appreciate them without taking into account the political circumstances by which they are affected. The influence of politics upon the two processes is however different. In regard to mobilization, which may be compared to a mechanical process, the statesman may urge its postponement or its execution by gradual instalments. In neither case is the essential nature of the operation changed, though the amount of friction involved may be increased. But the assembling of an army is the immediate preliminary to attack or defence, and the statesman's unwillingness to attack may affect the choice of time and place for the collection of the force available.