1. As regards their numerical strength and organisation.
2. In their state independent of fighting.
3. In respect of their maintenance; and, lastly,
4. In their general relations to country and ground.
Thus we shall devote this book to the consideration of things appertaining to an army, which only come under the head of _necessary conditions of fighting_, but do not constitute the fight itself. They stand in more or less close connection with and react upon the fighting, and therefore, in considering the application of the combat they must often appear; but we must first consider each by itself, as a whole, in its essence and peculiarities.
