ART. XLIV.--Formation and Employment of Infantry. ART. XLV.---Formation and Employment of Cavalry. ART. XLVI.---Formation and Employment of Artillery. ART. XLVII.--Employment of the Three Arms together. CONCLUSION. SUPPLEMENT. APPENDIX. SECOND APPENDIX. SKETCH OF THE PRINCIPAL MARITIME EXPEDITIONS. SUMMARY OF THE ART OF WAR. DEFINITION OF THE ART OF WAR. The art of war, as generally considered, consists of five purely military branches,--viz.: Strategy, Grand Tactics, Logistics, Engineering, and Tactics. A sixth and essential branch, hitherto unrecognized, might be termed _Diplomacy in its relation to War_. Although this branch is more naturally and intimately connected with the profession of a statesman than with that of a soldier, it cannot be denied that, if it be useless to a subordinate general, it is indispensable to every general commanding an army: it enters into all the combinations which may lead to a war, and has a connection with the various operations to be undertaken in this war; and, in this view, it should have a place in a work like this. To recapitulate, the art of war consists of six distinct parts:-- 1. Statesmanship in its relation to war. 2. Strategy, or the art of properly directing masses upon the theater of war, either for defense or for invasion. 3. Grand Tactics. 4. Logistics, or the art of moving armies. 5. Engineering,--the attack and defense of fortifications. 6. Minor Tactics. It is proposed to analyze the principal combinations of the first four branches, omitting the consideration of tactics and of the art of engineering. Familiarity with all these parts is not essential in order to be a good infantry, cavalry, or artillery officer; but for a general, or for a staff officer, this knowledge is indispensable. CHAPTER I. STATESMANSHIP IN ITS RELATION TO WAR. Under this head are included those considerations from which a statesman concludes whether a war is proper, opportune, or indispensable, and determines the various operations necessary to attain the object of the war. A government goes to war,-- To reclaim certain rights or to defend them; To protect and maintain the great interests of the state, as commerce, manufactures, or agriculture; To uphold neighboring states whose existence is necessary either for the safety of the government or the balance of power; To fulfill the obligations of offensive and defensive alliances; To propagate political or religious theories, to crush them out, or to defend them; To increase the influence and power of the state by acquisitions of territory; To defend the threatened independence of the state; To avenge insulted honor; or, From a mania for conquest.