The siege of Port Arthur by the Japanese and its defence by the Russians have thrown an entirely new light on Fortress Warfare. Although the main principles of the attack and defence remain unchanged and the primary armament of both is still the heavy artillery, the improvement of small-arms, their great range, and rapid fire have materially altered the nature of the fighting in the later stages and during the assault. The result of this has been to prolong the defence after the fortress has been dismantled by the bombardment, and to render the storming of a single breach an operation no longer possible in war. The machine gun is largely responsible for this; and when high-explosive shells have destroyed the fortifications and disabled the artillery, the stormers will be met by rifle fire and that of machine guns concealed among the ruins of the works. The intensity and accuracy of this fire will be such as to result frequently in the complete repulse of the assault, and even when the glacis of a work has been occupied it may be several weeks before the capture of the work itself is effected. Machine guns are particularly suited to the defence of fortresses during this period, and Sir G. S. Clarke, in his book _Fortification_, says: “The fire of the Maxim gun, delivering about 700 bullets a minute,[38] can be directed by one man, who need not show more than his head (easily shielded) above the parapet, the feed being tended by another man completely under cover. In the special qualities of the machine gun there is a distinct advantage to the defence, arising from the fact that _an intense fire over a particular area can be suddenly developed by a few men occupying a small space_. This, in the case of night attacks especially, is a valuable quality. At Port Arthur the Russians in some cases employed machine guns with good effect, concealing them so that their fire came as a surprise to the assaulting parties. Their portability renders them well suited for the defence of positions, and they will doubtless form an important element in the armament of fortresses.” Speaking of the difficulty of “storming” the modern fortress, the same author says: “The _vive force_ school proposed therefore--on paper--to shell them heavily and then storm, trusting to incomplete organisation and general unpreparedness. There is little or nothing in military history to bear out the views of this school, and modern experience is entirely against them. Only one such attempt was made in 1870-1, against the indifferent provisional works of Belfort, garrisoned mainly by _Gardes Mobiles_--and this failed completely. The tremendous assaults on the defences of Port Arthur may have been partially inspired by the German teaching; but the results were discouraging, although the devoted and sustained gallantry of the Japanese could not be surpassed and probably would not be equalled by any European army.”