"_Battle of Le Cateau_ (Oct. 6-12) IV., III., and I. Armies: 12,000 prisoners, 250 guns. "_Battle of the Selle_ (Oct. 17-25) IV. and III. Armies: 20,000 prisoners, 475 guns. "_Battle of the Sambre_ (Nov. 1-11) IV., III., and I. Armies: 19,000 prisoners, 450 guns." (Marshal Foch.) CHANGES IN METHOD.--The principles which underlie the Art of War would thus appear to be based on constant factors, but the methods of their application are susceptible to change, for in their application the principles are subject to the influence of successive inventions. Gunpowder abolished the bow and arrow and the knight in armour; the bayonet affixed to the musket superseded the pike; the rifle outranged the musket; the breech-loader and the magazine attachment progressively increased the rate of fire; smokeless powder rendered a firing line almost invisible; the flat trajectory of the small-arms bullet increased the danger-zone in an advance; the increased power, mobility, and accuracy of the field gun[4] rendered certain {22} formations obsolete in the attack; the general advance in the rate and accuracy of fire from rifles, machine guns, and artillery made attack on a strongly organised position possible only when surprise in the time and place of the thrust neutralises the advantages of the defence, or when an overwhelming barrage of shells and bullets covers the advance and smothers the enemy's resistance. The advent of a third service, by the addition of the Air to the Sea and Land Services, increased the facilities for reconnaissance[5] and added to the difficulties of concealing movement during the hours of daylight. These and similar influences have brought about changes in certain respects, amongst which the most pronounced is the increased use of field entrenchments, and tactical methods have been evolved to meet the necessities of the case, or modified to suit the new requirements.[6] But no inventions can shift the burden of war from the shoulders of the infantryman. "Despite the enormous development of mechanical invention in every phase of warfare, the place which the infantryman has always held as the main substance and foundation of an army is as secure to-day as in any period of history. The infantryman remains the backbone of defence and the spearhead of the attack. At no time has the reputation of the British infantryman been higher, or his achievement more worthy of his renown. . . . Immense as the influence of mechanical devices may be, they cannot by themselves decide a campaign. Their true _role_ is that of assisting the infantryman. . . . They cannot replace him. Only by the rifle and bayonet of the infantryman can the decisive victory be won" (Sir D. Haig's Dispatches). {23}