Although the sum of all military events which happen in all the Theatres of War in one year is often called a _Campaign_, still, however, it is more usual and more exact to understand by the term the events in _one single_ Theatre of War. But it is worse still to connect the notion of a Campaign with the period of one year, for wars no longer divide themselves naturally into Campaigns of a year’s duration by fixed and long periods in winter quarters. As, however, the events in a Theatre of War of themselves form certain great chapters—if, for instance, the direct effects of some more or less great catastrophe cease, and new combinations begin to develop themselves—therefore these natural subdivisions must be taken into consideration in order to allot to each year (Campaign) its complete share of events. No one would make the Campaign of 1812 terminate at Memel, where the armies were on the 1st January, and transfer the further retreat of the French until they recrossed the Elbe to the campaign of 1813, as that further retreat was plainly only a part of the whole retreat from Moscow. That we cannot give these conceptions any greater degree of distinctness is of no consequence, because they cannot be used as philosophical definitions for the basis of any kind of propositions. They only serve to give a little more clearness and precision to the language we use. CHAPTER III. Relation of Power In the eighth chapter of the third book we have spoken of the value of superior numbers in battles, from which follows as a consequence the superiority of numbers in general in strategy. So far the importance of the relations of power is established: we shall now add a few more detailed considerations on the subject. An unbiassed examination of modern military history leads to the conviction that the _superiority in numbers becomes every day more decisive;_ the principle of assembling the greatest possible numbers for a decisive battle may therefore be regarded as more important than ever.