Archduke Charles considered the subordination of tactics to strategy a law. “Tactics should execute the conceptions of strategy; where the two come in conflict, where strategical considerations are opposed to tactical interests, the strategical considerations should, as a rule, take precedence. Tactics must occupy a subordinate place and attempt to neutralize existing disadvantages by skillful dispositions.” Clausewitz not unjustly censures Archduke Charles for placing advantages of terrain in the first rank, and for failing to attach the proper importance to the annihilation of the hostile forces. Should the demands of strategy conflict with those of tactics on the battlefield, the latter must unquestionably take precedence, since the general’s foremost thought must be the annihilation of the hostile forces. Tactical considerations should likewise govern in the selection of the direction of attack in a battle, strategical reasons for striking in this or that direction becoming effective only after the attainment of tactical success. It is true that strategy, by directing the armies and their concentration on the battlefield, provides tactics with the tools for fighting and assures the probability of victory; but, on the other hand, the commander-in-chief appropriates the fruits of each victory and makes them the basis for further plans. “The demands of strategy are silent in the presence of tactical victory; they adapt themselves to the newly created situation.” Fieldmarshal MOLTKE.[11] [11] The view that the direction of attack should be governed by the possibility of easy execution in minor warfare only, is held by General v. Scherff, who says: “General v. Moltke was not influenced by the question ‘will the attack here or there be tactically easier or more difficult?’ Only the question, ‘will it there be strategically advantageous or not’ was able to determine his course with reference to measures on the battlefield.” 3. THE METHOD OF INSTRUCTION. While Archduke Charles considers mathematical axioms the basis of the higher art of war, military history is for us the principal source from which to gather knowledge.[12] [12] See lecture by Prince HOHENLOHE: _Kriegserfahrung und Kriegsgeschichte_, Neisse, 1879. “Let my son often read and meditate upon history; it is the only true philosophy. Let him often read and meditate upon the wars of the great captains; it is the only means of learning the art of war.” NAPOLEON I., on April 17th, 1821. “Past events are useful to feed the imagination and furnish the memory, provided their study is the repetition of ideas that judgment should pass upon.” FREDERICK THE GREAT.