An ingenious author tried to concentrate in a single conception, that of a BASE, a whole host of objects amongst which sundry relations even with immaterial forces found their way in as well. The list comprised the subsistence of the troops, the keeping them complete in numbers and equipment, the security of communications with the home country, lastly, the security of retreat in case it became necessary; and, first of all, he proposed to substitute this conception of a base for all these things; then for the base itself to substitute its own length (extent); and, last of all, to substitute the angle formed by the army with this base: all this was done to obtain a pure geometrical result utterly useless. This last is, in fact, unavoidable, if we reflect that none of these substitutions could be made without violating truth and leaving out some of the things contained in the original conception. The idea of a base is a real necessity for strategy, and to have conceived it is meritorious; but to make such a use of it as we have depicted is completely inadmissible, and could not but lead to partial conclusions which have forced these theorists into a direction opposed to common sense, namely, to a belief in the decisive effect of the enveloping form of attack. 11. INTERIOR LINES. As a reaction against this false direction, another geometrical principle, that of the so-called interior lines, was then elevated to the throne. Although this principle rests on a sound foundation, on the truth that the combat is the only effectual means in War, still it is, just on account of its purely geometrical nature, nothing but another case of one-sided theory which can never gain ascendency in the real world. 12. ALL THESE ATTEMPTS ARE OPEN TO OBJECTION. All these attempts at theory are only to be considered in their analytical part as progress in the province of truth, but in their synthetical part, in their precepts and rules, they are quite unserviceable. They strive after determinate quantities, whilst in War all is undetermined, and the calculation has always to be made with varying quantities. They direct the attention only upon material forces, while the whole military action is penetrated throughout by intelligent forces and their effects. They only pay regard to activity on one side, whilst War is a constant state of reciprocal action, the effects of which are mutual. 13. AS A RULE THEY EXCLUDE GENIUS. All that was not attainable by such miserable philosophy, the offspring of partial views, lay outside the precincts of science—and was the field of genius, which RAISES ITSELF ABOVE RULES. Pity the warrior who is contented to crawl about in this beggardom of rules, which are too bad for genius, over which it can set itself superior, over which it can perchance make merry! What genius does must be the best of all rules, and theory cannot do better than to show how and why it is so.