on account of the quarters and camping ground, in the other we take the quarters and camps such as they are, on account of the road. When a battle is expected, and everything depends on our reaching a particular point with a mass of troops, then we should think nothing of getting to that point by even the worst by-roads, if necessary; if, on the other hand, we are still on the journey to the theatre of war, then the nearest great roads are selected for the columns, and we look out for the best quarters and camps that can be got near them.
Whether the march is of the one kind or the other, if there is a possibility of a combat, that is within the whole region of actual war, it is an invariable rule in the modern art of war to organise the columns so that the mass of troops composing each column is fit of itself to engage in an independent combat. This condition is satisfied by the combination of the three arms, by an organised subdivision of the whole, and by the appointment of a competent commander. Marches, therefore, have been the chief cause of the new order of battle, and they profit most by it.
When in the middle of the last century, especially in the theatre of war in which Frederick II. was engaged, generals began to look upon movement as a principle belonging to fighting, and to think of gaining the victory by the effect of unexpected movements, the want of an organised order of battle caused the most complicated and laborious evolutions on a march. In carrying out a movement near the enemy, an army ought to be always ready to fight; but at that time they were never ready to fight unless the whole army was collectively present, because nothing less than the army constituted a complete whole. In a march to a flank, the second line, in order to be always at the regulated distance, that is about a quarter of a mile from the first, had to march up hill and down dale, which demanded immense exertion, as well as a great stock of local knowledge; for where can one find two good roads running parallel at a distance of a quarter of a mile from each other? The cavalry on the wings had to encounter the same difficulties when the march was direct to the