there is no indication that any general staff in Europe is alive to the possibilities they present in defence. As already pointed out, the assailant cannot count on their aid once he has penetrated within the enemy's country, and the farther he advances the worse matters become for him. It is enough to consider an invading force based on the east coast of Yorkshire with its head about Leeds; the technical excellence of English railways is so great that 1 20,000 men with all their share of guns and necessary equipment could be easily transferred say from Glasgow and Edinburgh round to Sheffield in twenty-four hours for a flank attack. Even double that number, from the south of England to the north of Yorkshire, could be moved in the same time. It is not suggested that such movements, might be in themselves desirable, but only that in face of such mobility of masses, no calculation of the enemy's movements would be possible.
In conclusion, the man who would fit himself for the highest commands in war, or even for the criticism, of those who exercise them, must never for one moment forget that the momentary spirit of the mass he directs is the fundamental condition of the success of every movement. Just as there is no movement so simple that its success may not be jeopardized by ill-will and despondency in execution, there is hardly any limit to what willing men can achieve, and it has been this power of evoking in their commands the spirit of blind trust and confidence that places men like Cromwell, Marlborough, Frederick and Napoleon almost beyond reproach. By the side of this power the technical knowledge and ingenuity displayed in their several undertakings appear quite trivial; probably the same ideas have occurred to thousands of quite mediocre men, but were never put into execution, because they could not count on the whole-souled devotion of their men to execute them. This power is born in a man, not acquired, but even those who possess it in embryo can increase and develop it enormously by a systematic study of the laws which govern the action of humanity in the mass.
From the above we arrive at the following definitions for the terms most generally employed by writers on military history and strategy.
Base. â€” The point, or line joining a series of points, from whence military operations originate. Ultimately military operations have their inception in an area, i.e. a whole country from which organization draws men, arms, food and material of all descriptions, forwarding them through a network of communications â€” roads, railways, canals, rivers, &c, and delivering them at points as near to the proposed enemy as circumstances render expedient. As an army never has too many men, and normal civil transport is cheaper in every way than military, the tendency is always to maintain the collection of men and materials under civil administration as long as possible. Thus as an army moves forward, settling the district behind it as it advances, the civil administration follows after it, only ceasing to exercise its functions when these can be no longer carried out without military protection. Generally there is a zone in which civil transport and supply exist side by side with military precautions greater or less, but for all practical purposes each column, whatever its strength, has its " base " at that point where the existing magazines are filled by civilian con- tractors in the ordinary course of trade, and with no extra charge for war risks.
Line of Communication. â€” The line of communication is the great main road, trunk railway, canal or river, or any combination of these means, for the transport of stores leading from the base to the army at the front. Along these arteries of communication depots are established, military authority commands, and every arrangement is made that foresight can suggest to meet the abnormal demands that a condition of war naturally gives rise to. Napoleon always used the words route de Varmee, which conveyed perhaps a clearer idea of the conditions the road or other means of com- munication had to comply with than the current term. In propor- tion to the numbers which have to be supplied by this line of communication its importance naturally increases. Thus whereas in 1870 the Germans on the Loire had a choice of magnificent main roads, even of canals and railroads, and if one were temporarily interrupted could switch off the current of supply to another without great inconvenience, the Russians in 1904 were tied to a single railway, any interruption of which must have paralysed altogether their vast army which ultimately numbered 400,000 mouths to be fed. It is clear, therefore, that the importance attaching to the protection of the line of communications must vary in accordance with the nature of the country in which war is carried on, the state of its communications of all sorts, the facility for establishing new ones, and the number of men depending for subsistence on any single road, railway, river or canal.
Line of Operations is a term applied to an imaginary line drawn from the centre of gravity of the army at the front to the country from which it originates. Whereas lines of communication, being dependent on the topographical conformation of the district may be highly circuitous; the line of operations is merely a general direction more convenient to keep in mind than the more complex idea embodied in the former word. Since practically all supply flows to an army along its line or lines of communication, and without them it can only exist for a limited period, practically all situations that can arise in war can be referred to their possible consequences in endangering more or less either one's own communications or those of the enemy. An army is thus said to " form front to a flank " when its communications run parallel to the direction it assumes when facing the enemy (see diagram). It is clear that in case of a defeat at or near A the communications are most gravely endangered, hence no commander voluntarily assumes such a posi- tion "unless he is absolutely confident in the power of his troops to beat the enemy and by so doing places his antagonist in even a worse position in case of defeat. This he can only do by placing himself more or less astride his adversaries' communications, when the latter if beaten is ruined beyond retrieval. Thus in the Marengo campaign, in 1800, Napoleon, in placing himself astride the Austrian communications, was himself compelled to form front to a flank, but this was only possible because the geographical relation of the French and Italian frontiers enabled him from the outset of the campaign to aim a blow in the rear of his opponents' actual front. Under modern conditions such situations in war between two great land powers can hardly arise. The preliminary concentration of armies is arranged in peace in such a manner that both armies will always start with their communications perpendicularly behind^ them. Hence though the advantage which can be gained by defeating an army when forming front to a flank is equally great, it cannot be attained except by accepting a corresponding risk, and the same holds good if one army places itself astride the com- munications of another, e.g. the Germans at Gravelotte. But when a land army has to deal with a great sea power controlling the va,st mercantile navies of the present day, the latter being free to land wherever he pleases can compel his adversary to form front to a flank almost as he pleases. This was the advantage Wellington derived from sea power in the campaign of Vittoria (see Peninsular War), and there are many theatres of war in which the operation might be repeated nowadays, for though armies have grown ten- fold in numbers the means of carrying them with certainty and speed have increased in a yet greater ratio. As between land powers the question may be complicated when the frontier is formed by some great natural obstacle, a great river or range of mountains. There can be an almost infinite range of gradation between the imagin- ary line marked across a plain by boundary pillars, and the hard and fast distinction drawn between sea and land. The advantage, however, always lies on the side of the nation that possesses behind such barrier the better means of lateral communications. Those on land can never be so good as the sea, but in proportion as they approach that ideal their possessor can transfer masses of men in complete security and comparative secrecy, to whichever portion of the frontier may suit his purpose best.
Exterior Lines. â€” When armies operate from several bases by lines converging on an army centrally situated as regards them, they are said to operate on exterior lines, and conversely the army operating from a centre against armies converging upon it is said to be acting on " interior lines." The question of the relative superiority of the one form or the other has been discussed above. It is only necessary to point out here that the question again is one of mobility in its widest sense, i.e. the mobility resulting from better communications both of intelligence, orders and the actual material forces by which war is made. Owing to the configuration of frontiers, it may be absolutely necessary to attack on exterior lines, but once the convergence these imply has been attained, and a victory won, the advantage of the form, which is derived from the superiority of communications at the disposal of the nation acting from the broader base, passes over to the defender, who destroying all railways, &c. in his retreat, compels the assailant to advance by route marching only, whereas as he, the defender, falls back within his own territory, he preserves unimpeded control over his own railways, and can thus transfer troops from one flank of the assailant to another, as the case may require.
Obstacles. â€” All obstacles, whether formed by rivers, marshes, forests or mountains, are of value in strategy only in so far as they delay the rapidity of communications by limiting the number of the available means of transport, whether roads or railways, and whatever angle they may form with the line of operations of the contending forces the advantage they offer falls entirely to the side that commands the exits of the defiles by which they are traversed on the farther side. When neither side commands such exits from the outset, the advantage falls to the side which can accumulate first at the desired point of passage a sufficient fire superiority to cover his subsequent necessary operations; in the case of a river, the building of one or several bridges ; in the case of a mountain range, the deployment of his advance-guard. In the former case there is no particular reason why the facilities of communication should be greater on one bank than the other. In the latter the