Concentration, therefore, in this case, could only be effected by a sacrifice; consequently in any particular instance, the question to be decided would be, Is the necessity for concentration so great that this sacrifice must be made?
- The attack by separate lines may offer greater results.
As we are now speaking of advancing by separate lines against one centre of force, we are, therefore, supposing an advance by converging lines. A separate advance on parallel or eccentric lines belongs to the rubric of accessory undertakings, of which we have already spoken.
Now, every convergent attack in strategy, as well as in tactics, holds out the prospect of great results; for if it succeeds, the consequence is not simply a defeat, but more or less the cutting off of the enemy. The concentric attack is, therefore, always that which may lead to the greatest results; but on account of the separation of the parts of the force, and the enlargement of the theatre of war, it involves also the most risk; it is the same here as with attack and defence, the weaker form holds out the greater results in prospect.
The question, therefore, is, whether the assailant feels strong enough to try for this great result.
When Frederick the Great advanced upon Bohemia, in the year 1757, he set out from Saxony and Silesia with his forces divided. The two principal reasons for his doing so were, first, that his forces were so cantoned in the winter that a concentration of them at one point would have divested the attack of all the advantages of a surprise; and next, that by this concentric advance, each of the two Austrian theatres of war was threatened in the flanks and the rear. The danger to which Frederick the Great exposed himself on that occasion was that one of his two armies might have been completely defeated by superior forces; should the Austrians not see this , then they would have to give battle with their