A history of military method for the last few centuries would be a record of successive alternate steps in which offensive and defensive contrivances pull ahead, first one and then the other. Their relative fluctuations are marked by the varying length of campaigns. From the very outset we have the ditch and the wall; the fortified place upon a pass or main road, as a check to the advance. Artillery improves, then fortification improves. The defensive holds its own for a long period, wars are mainly siege wars, and for a century before the advent of Napoleon there are no big successful sweeping invasions, no marches upon the enemy capital and so on. There were wars of reduction, wars of annoyance. Napoleon developed the offensive by seizing upon the enthusiastic infantry of the republic, improving transport and mobile artillery, using road-making as an aggressive method. In spite of the successful experiment of Torres Vedras and the warning of Plevna the offensive remained dominant throughout the nineteenth century. But three things were working quietly towards the rehabilitation of the defensive; firstly the increased range, accuracy and rapidity of rifle fire, with which we may include the development of the machine gun; secondly the increasing use of the spade, and thirdly the invention of barbed wire. By the end of the century these things had come so far into military theory as to produce the great essay of Bloch, and to surprise the British military people, who are not accustomed to read books or talk shop, in the Boer war. In the thinly populated war region of South Africa the difficulties of forcing entrenched positions were largely met by outflanking, the Boers had only a limited amount of barbed wire and could be held down in their trenches by shrapnel, and even at the beginning of the present war there can be little doubt that we and our Allies were still largely unprepared for the full possibilities of trench warfare, we attempted a war of manoeuvres, war at about the grade to which war had been brought in 1898, and it was the Germans who first brought the war up to date by entrenching upon the Aisne. We had, of course, a few aeroplanes at that time, but they were used chiefly as a sort of accessory cavalry for scouting; our artillery was light and our shell almost wholly shrapnel.