As the march is the instrument by which strategy apportions its active elements, the combats, but these last often only appear by their results and not in the details of their real course, it could not fail to happen that in theory the instrument has often been substituted for the efficient principle. Thus we hear of a decisive skilful march, allusion being thereby made to those combat-combinations to which these marches led. This substitution of ideas is too natural and conciseness of expression too desirable to call for alteration, but still it is only a condensed chain of ideas in regard to which we must never omit to bear in mind the full meaning, if we would avoid falling into error. We fall into an error of this description if we attribute to strategical combinations a power independent of tactical results. We read of marches and manœuvres combined, the object attained, and at the same time not a word about combat, from which the conclusion is drawn that there are means in War of conquering an enemy without fighting. The prolific nature of this error we cannot show until hereafter. But although a march can be regarded absolutely as an integral part of the combat, still there are in it certain relations which do not belong to the combat, and therefore are neither tactical nor strategic. To these belong all arrangements which concern only the accommodation of the troops, the construction of bridges, roads, &c. These are only conditions; under many circumstances they are in very close connection, and may almost identify themselves with the troops, as in building a bridge in presence of the enemy; but in themselves they are always activities, the theory of which does not form part of the theory of the conduct of War. Camps, by which we mean every disposition of troops in concentrated, therefore in battle order, in contradistinction to cantonments or quarters, are a state of rest, therefore of restoration; but they are at the same time also the strategic appointment of a battle on the spot, chosen; and by the manner in which they are taken up they contain the fundamental lines of the battle, a condition from which every defensive battle starts; they are therefore essential parts of both strategy and tactics. Cantonments take the place of camps for the better refreshment of the troops. They are therefore, like camps, strategic subjects as regards position and extent; tactical subjects as regards internal organisation, with a view to readiness to fight.